Re: HP 8568B from hell to Heaven... a restoration story!
Salve Andrea,
Welcome with us!
I can smell there the beginning of a good serial. Don't make us wait to much for #2...
Best
Renaud
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Re: Leaking alkaline cells
On 9/7/2024 2:07 AM, Richard Knoppow wrote:
?NOt sure what the guarantee means, will they replace defective cells or replace the equipment they ruin? Don't know. "Our 100% satisfaction guarantee: If you are not 100% satisfied, we are very sorry." -- sign in window of a Piggly Wiggly in Little Rock, AR around 1985 -- Prof. Thomas H. Lee Allen Ctr., Rm. 205 420 Via Palou Mall Stanford University Stanford, CA 94305-4070
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Re: Leaking alkaline cells
The dimples are only on the AA size cells but other sizes leaked. I don't know what the problem was or how Duracell fixed it, I noticed the change in the AA cells and it indicated to me that they had changed something. So far I have not had leakage problems with the new versions. However, I have not tested them for capacity or other qualities. I originally adopted Duracells on the advice of a friend to did motion picture production sound. He used a Nagra (as did most recorders) and found he got the longest life from Duracels. He also found that they weighed more and that the service capacity seemed to be related to weight. In any case, I had good results from Duracells until they began to fail with leakage. Not sure when that was. Initially, they were made by Mallory. For whatever reason Mallory sold the product to someone else and the troubles started sometime after that. Was it a bean counter problem or was there a change in some ingredient, I have no idea. Its easy to blame bean counters and they are often at fault when an established product hits the skids for quality. But, there can be other causes. In any case Duracell is now running to catch up after their debacle so are worth trying. NOt sure what the guarantee means, will they replace defective cells or replace the equipment they ruin? Don't know.
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On 9/7/2024 1:29 AM, Tom Lee wrote: Thanks very much for that information, Richard. I had long ago written off Duracells as equipment-destroying junk. I'll give them another go. I'll just have to remember "no dimples, no leak."
-- Tom
--
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998
|
Re: Leaking alkaline cells
Thanks very much for that information, Richard. I had long ago written off Duracells as equipment-destroying junk. I'll give them another go. I'll just have to remember "no dimples, no leak."
-- Tom
--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
420 Via Palou Mall
Stanford University
Stanford, CA 94305-4070
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On 9/7/2024 1:19 AM, Richard Knoppow wrote: ?? I don't think Duracell is the worst at the moment. They removed the product from the market for several months and came back with a much improved one.? {snip} The leaking AA cells had two little dimples on the bottom, new ones do not.
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Re: Leaking alkaline cells
I don't think Duracell is the worst at the moment. They removed the product from the market for several months and came back with a much improved one. Maybe two years ago. I stopped using Duracell and Kirkland batteries when I discovered many leaking cells and found brand new batteries leaking in their packages. When they announced the problem was fixed I bought some to test them. So far, pretty good. I have had leakage problems in the past but nothing like what was happening with Duracell. The appearance of the cells is different. The leaking AA cells had two little dimples on the bottom, new ones do not. I think they realized their business was being ruined and put forth an earnest effort to correct it. The problem is that its much harder to overcome a bad reputation than to create a good one to begin with.
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On 9/6/2024 11:47 PM, Froggie the Gremlin wrote: Duracell is now the worst, ALL leak badly and ruin electronics.
We switched to Amazon brands, and check the type and reviews before purchasing
The Panasonic NiMh rechargeable are OK, though costly and low capacity.
The damages of leak's are usually easy to clean with Q tips, water, isopropyl alcohol, or vinegar, baking soda and small wire brushes.
--
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998
|
Re: Leaking alkaline cells
Duracell is now the worst, ALL leak badly and ruin electronics.
We switched to Amazon brands, and check the type and reviews before purchasing
The Panasonic NiMh rechargeable are OK, though costly and low capacity.
The damages of leak's are usually easy to clean with Q tips, water, isopropyl alcohol, or vinegar, baking soda and small wire brushes.
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Re: Leaking alkaline cells
Oh crap that means I¡¯m old.
Peter
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On Sep 7, 2024, at 12:46?AM, Chuck Harris via groups.io <cfharris@...> wrote:
?Back in the days of yor, a carbon-zinc cell was a zinc
can, wrapped in paper, and filled with sawdust and sal
ammoniac electrolyte, and finally a zinc electrode.
The carbon rod electrode was surrounded by a manganese
compound that improved the discharge capacity of the
cell.
When the zinc can was consumed, it etched through and
the ammonium salt solution leaked all over things.
When the heavy duty carbon-zinc cells were created, they
had the zinc can inside of a steel can that was lined
with an absorbant paper, and plastic seal. They rarely
leaked.
If you are younger than 60, you might never have seen
the old style, except for possibly some old Burgess
No.6 "ignition cells". Really big things that ran the
buzzer type of ignition coils on Model T Fords, and other
ancient cars.
-Chuck Harris
On Fri, 6 Sep 2024 15:02:55 -0700 "Andrew Hakman"
<andrew.hakman@...> wrote:
So I was obviously wrong about my comment that Zinc Carbon batteries
don't leak, and I did some "research" (aka found my box of dead
batteries, took some pictures, and used google translate). The super
light batteries that don't leak that come with remotes I was thinking
of are Manganese batteries apparently, and they are marked "DRY
BATTERY" on them. It's quite possible that I've never actually seen a
Zinc Carbon battery in real life, as these are the ones I always
thought were Zinc Carbon. I know some people say the Zinc Carbon are
marked "Heavy Duty" as this one is, and I jumped to the wrong
conclusion.
[image: battery1.jpg]
[image: battery2.jpg]
On Fri, Sep 6, 2024 at 1:00?PM Adrian Godwin via groups.io <artgodwin=
[email protected]> wrote:
I have a 3D maglite that was badly corroded by energisers (though,
I'm not sure if UK energisers are the same as US ones). After
cleaning it out iot wasn't too bad, just some roughness on the
internal surface. The corrosion was in the middle and hadn't
reached the switch or cap.
I replaced with Nicad obtained somewhere cheaply (but new, decent
industrial ones, probably intended for emergency light backup).
This would have resulted in dim light but I also replaced the bulb
with an LED one with a switching regulator making it insensitive to
low batteries. The result is pretty good.
Another way to get around low voltage cells is the batteriser boost
regulator. They don't extend battery life anywhere near as long as
claimed and aren't very useful for modern devices that can tolerate
low voltage, but they will bring nicads/NiMH up to alkaline levels,
useful for fussy older devices. The downside is they will try to
suck every joule out of the cell - not the best way to look after
rechargeables. I believe they now have a version that cuts out at
NiMH end voltage.
For PP3s, there are some lipo-based versions with a USB C charging
port. These give full 9V, unlike earlier NiMH which were low
voltage (though some had 7 cells instead of 6 to compensate). I've
got a couple of these lithium ones and am so far pleased with them
but haven't done a long-term test.
Attachments:
battery1.jpg:
/g/HP-Agilent-Keysight-equipment/attachment/146808/0
battery2.jpg:
/g/HP-Agilent-Keysight-equipment/attachment/146808/1
|
Re: Leaking alkaline cells
In practice a small leak won¡¯t cause anything spectacular. The solvent portion of the electrolyte will evaporate and some moisture will get in and the cell will die. It would be hard to force enough water inside to cause a significant energetic reaction. I know because I get to do this at work as part of product DFMEA.
What does happen with a poor seal is reduced shelf life and that would be a significant quality issue. The seals are pretty darn good and a science all unto themselves.
Regarding charging lithium ion cell devices, yeah, don¡¯t do that on couches or next to you in your bed.
Peter
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On Sep 7, 2024, at 12:34?AM, Chuck Harris via groups.io <cfharris@...> wrote:
?If a lithium primary cell were to leak, there would be a
lot of heat, a great expulsion of hydrogen and oxygen,
as well as CO2 gases, and possibly an explosion.
Lithium and water vapor make for an exciting time, special
effort must be made to make sure that cannot happen.
Do, however think about that, when you put your lithium
secondary cell powered devices on say, your couch, or a
stack of newspapers, while they are being charged or
discharged.
-Chuck Harris
On Fri, 06 Sep 2024 06:10:38 -0700 "Ed Marciniak" <edr10000@...>
wrote:
While my sample size isn¡¯t insanely huge, over the last 25 years I¡¯ve
never seen an Energizer lithium AA,AAA or 9V leak. I¡¯ve never seen a
lithium 9V in any other brand leak either.
|
Re: Leaking alkaline cells
Back in the days of yor, a carbon-zinc cell was a zinc can, wrapped in paper, and filled with sawdust and sal ammoniac electrolyte, and finally a zinc electrode. The carbon rod electrode was surrounded by a manganese compound that improved the discharge capacity of the cell. When the zinc can was consumed, it etched through and the ammonium salt solution leaked all over things. When the heavy duty carbon-zinc cells were created, they had the zinc can inside of a steel can that was lined with an absorbant paper, and plastic seal. They rarely leaked. If you are younger than 60, you might never have seen the old style, except for possibly some old Burgess No.6 "ignition cells". Really big things that ran the buzzer type of ignition coils on Model T Fords, and other ancient cars. -Chuck Harris On Fri, 6 Sep 2024 15:02:55 -0700 "Andrew Hakman" <andrew.hakman@...> wrote: So I was obviously wrong about my comment that Zinc Carbon batteries
don't leak, and I did some "research" (aka found my box of dead
batteries, took some pictures, and used google translate). The super
light batteries that don't leak that come with remotes I was thinking
of are Manganese batteries apparently, and they are marked "DRY
BATTERY" on them. It's quite possible that I've never actually seen a
Zinc Carbon battery in real life, as these are the ones I always
thought were Zinc Carbon. I know some people say the Zinc Carbon are
marked "Heavy Duty" as this one is, and I jumped to the wrong
conclusion.
[image: battery1.jpg]
[image: battery2.jpg]
On Fri, Sep 6, 2024 at 1:00?PM Adrian Godwin via groups.io <artgodwin=
[email protected]> wrote:
I have a 3D maglite that was badly corroded by energisers (though,
I'm not sure if UK energisers are the same as US ones). After
cleaning it out iot wasn't too bad, just some roughness on the
internal surface. The corrosion was in the middle and hadn't
reached the switch or cap.
I replaced with Nicad obtained somewhere cheaply (but new, decent
industrial ones, probably intended for emergency light backup).
This would have resulted in dim light but I also replaced the bulb
with an LED one with a switching regulator making it insensitive to
low batteries. The result is pretty good.
Another way to get around low voltage cells is the batteriser boost
regulator. They don't extend battery life anywhere near as long as
claimed and aren't very useful for modern devices that can tolerate
low voltage, but they will bring nicads/NiMH up to alkaline levels,
useful for fussy older devices. The downside is they will try to
suck every joule out of the cell - not the best way to look after
rechargeables. I believe they now have a version that cuts out at
NiMH end voltage.
For PP3s, there are some lipo-based versions with a USB C charging
port. These give full 9V, unlike earlier NiMH which were low
voltage (though some had 7 cells instead of 6 to compensate). I've
got a couple of these lithium ones and am so far pleased with them
but haven't done a long-term test.
Attachments:
battery1.jpg:
/g/HP-Agilent-Keysight-equipment/attachment/146808/0
battery2.jpg:
/g/HP-Agilent-Keysight-equipment/attachment/146808/1
|
Re: HP 141T Power Supply Help Needed
Bill,
?
If you haven't already, you need to isolate the A1 and A2 boards from the rest of unit.? You're making this harder than it has be if you haven't already.
?
Also, earlier you mentioned measuring R44 as 18k.? It is a 20k resistor with 1% tolerance.? That is 10% tolerance.? Most of the resistors on the A2 board are 1% tolerance.? It is well documented in the 140, 180 series mainframes that when these resistors go out of spec, they can bring the whole supply down. Make sure to reference the parts list of the manual.??
?
Pots and trim pots are also worth a close look on these units.? I've found faulty ones in these mainframes that cause funky symptoms.
?
-Frank
|
Re: Leaking alkaline cells
Every lithium primary cell I have found measures about 1.7 to 1.8V when under low loading, and drops down to 1.5'ishV, under normal load. I might think that could be a problem in some cases. -Chuck Harris On Fri, 6 Sep 2024 08:13:50 -0400 "Peter Gottlieb" <hpnpilot@...> wrote: "Cost prohibitive" in a very narrow sense as the added cost is small.
But the business decision is that in the highly competitive and high
markup retail battery market, consumers aren't smart enough to buy
based on quality in terms of leakage so go for the cheapest possible
product to make and rake in the cash.
The Eveready ultimate lithium are lithium iron disulfide with a
metallic lithium electrode.? Lithium metal is extremely sensitive to
moisture so these cells due to their chemistry must have a superior
seal.? Obviously the electrolyte must also be non-aqueous as well,
resembling that of lithium ion cells.? This is far less corrosive
which helps keep the seals, sealed.
Yes these cells sell at a significant premium over alkaline cells.
For a family with kids who go through dozens of cells a month in toys
they probably aren't worth it but for cells used in anything valuable
or that you have on the shelf and want to have ready to use the
premium for a cell which is highly unlikely to leak is worth it.
Do not buy these lithium ultimate cells retail, the markup makes the
cost outrageous.? They have long shelf life so look for sales of the
larger quantity bulk packages or go online and find the sales in bulk
packages.? Then the premium is reasonable.
Peter
On 9/6/2024 12:27 AM, tgerbic via groups.io wrote:
I worry about battery leakage as well and have not found a battery
brand today that does not leak. I do remember some brands back in
the 60s or 70s did not seem to leak but things escalated over the
decades to all brands seem to leak. I think it has reached a point
where companies just expect that consumers assume all batteries
leak so not much consumers can do about it. Quality in general is
not really a high With that said, I bought a bunch of old Heathkit
gear filled with the old Radio Shack C batteries about 8 years ago,
perhaps two dozen batteries were removed. As expected they were all
dead batteries but every one was in pristine condition, almost
looked clean enough to eat off of. Not even a hint of leakage. I
know they were probably 20 years old but but it was almost
unbelievable.? So it is possible to make non-leaking batteries but
probably cost prohibitive today. --
T. Gerbic
Central California
|
Re: Leaking alkaline cells
If a lithium primary cell were to leak, there would be a lot of heat, a great expulsion of hydrogen and oxygen, as well as CO2 gases, and possibly an explosion. Lithium and water vapor make for an exciting time, special effort must be made to make sure that cannot happen. Do, however think about that, when you put your lithium secondary cell powered devices on say, your couch, or a stack of newspapers, while they are being charged or discharged. -Chuck Harris On Fri, 06 Sep 2024 06:10:38 -0700 "Ed Marciniak" <edr10000@...> wrote: While my sample size isn¡¯t insanely huge, over the last 25 years I¡¯ve
never seen an Energizer lithium AA,AAA or 9V leak. I¡¯ve never seen a
lithium 9V in any other brand leak either.
|
Re: Leaking alkaline cells
I have no photos of what I believe were carbon zinc cells but used plenty of them in the past. Common brands were Bright Star, Ray-O-Vac, Burgess for Size-D and some other brands for No.6 size, AKA telephone or ignition cells. AT&T made telephone cells with names like Blue Bell and Columbia. I am old enough to remember magneto phones out in the country, phone company would come about twice a year to replace the large cells in them.
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On 9/6/2024 6:31 PM, Michael A. Terrell wrote: "A zinc anode, a manganese dioxide cathode, and an ammonium chloride or zinc chloride electrolyte that is dissolved in water make up the zinc carbon cell. The cathode mix is often a moist mixture of specific carbon black, manganese dioxide powder, an electrolyte, and a solution.
Back in the '60s, Mallory sold really low grade AA cells. There was no case over the zinc shell, just a paper label. The zinc was so thin that as a little jid I could deform the between two fingers. They leaked like crazy, but they sold for just 5 cents at a local mom ^ pop store.
On Fri, Sep 6, 2024 at 6:03?PM Andrew Hakman via groups.io <> <andrew.hakman@... <mailto:[email protected]>> wrote:
So I was obviously wrong about my comment that Zinc Carbon batteries
don't leak, and I did some "research" (aka found my box of dead
batteries, took some pictures, and used google translate). The super
light batteries that don't leak that come with remotes I was
thinking of are Manganese batteries apparently, and they are marked
"DRY BATTERY" on them. It's quite possible that I've never actually
seen a Zinc Carbon battery in real life, as these are the ones I
always thought were Zinc Carbon. I know some people say the Zinc
Carbon are marked "Heavy Duty" as this one is, and I jumped to the
wrong conclusion.
battery1.jpg
battery2.jpg
On Fri, Sep 6, 2024 at 1:00?PM Adrian Godwin via groups.io
<> <artgodwin@...
<mailto:[email protected]>> wrote:
I have a 3D maglite that was badly corroded by energisers
(though, I'm not sure if UK energisers are the same as US ones).
After cleaning it out iot wasn't too bad, just some roughness on
the internal surface. The corrosion was in the middle and hadn't
reached the switch or cap.
I replaced with Nicad obtained somewhere cheaply (but new,
decent industrial ones, probably intended for emergency light
backup). This would have resulted in dim light but I also
replaced the bulb with an LED one with a switching regulator
making it insensitive to low batteries. The result is pretty good.
Another way to get around low voltage cells is the batteriser
boost regulator. They don't extend battery life anywhere near as
long as claimed and aren't very useful for modern devices that
can tolerate low voltage, but they will bring nicads/NiMH up to
alkaline levels, useful for fussy older devices. The downside is
they will try to suck every joule out of the cell - not the best
way to look after rechargeables. I believe they now have a
version that cuts out at NiMH end voltage.
For PP3s, there are some lipo-based versions with a USB C
charging port. These give full 9V, unlike earlier NiMH which
were low voltage (though some had 7 cells instead of 6 to
compensate). I've got a couple of these lithium ones and am so
far pleased with them but haven't done a long-term test.
--
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998
|
Re: Leaking alkaline cells
"A zinc anode, a manganese dioxide cathode, and an ammonium chloride or zinc chloride electrolyte that is dissolved in water make up the zinc carbon cell. The cathode mix is often a moist mixture of specific carbon black, manganese dioxide powder, an electrolyte, and a solution. Back in the '60s, Mallory sold really low grade AA cells. There was no case over the zinc shell, just a paper label. The zinc was so thin that as a little jid I could deform the between two fingers. They leaked like crazy, but they sold for just 5 cents at a local mom ^ pop store.
On Fri, Sep 6, 2024 at 6:03?PM Andrew Hakman via <andrew.hakman= [email protected]> wrote: So I was obviously wrong about my comment that Zinc Carbon batteries don't leak, and I did some "research" (aka found my box of dead batteries, took some pictures, and used google translate). The super light batteries that don't leak that come with remotes I was thinking of are Manganese batteries apparently, and they are marked "DRY BATTERY" on them. It's quite possible that I've never actually seen a Zinc Carbon battery in real life, as these are the ones I always thought were Zinc Carbon. I know some people say the Zinc Carbon are marked "Heavy Duty" as this one is, and I jumped to the wrong conclusion.
On Fri, Sep 6, 2024 at 1:00?PM Adrian Godwin via <artgodwin= [email protected]> wrote: I have a 3D maglite that was badly corroded by energisers (though, I'm not sure if UK energisers are the same as US ones). After cleaning it out iot wasn't too bad, just some roughness on the internal surface. The corrosion was in the middle and hadn't reached the switch or cap.
?
I replaced with Nicad obtained somewhere cheaply (but new, decent industrial ones, probably intended for emergency light backup). This would have resulted in dim light but I also replaced the bulb with an LED one with a switching regulator making it insensitive to low batteries. The result is pretty good.
?
Another way to get around low voltage cells is the batteriser boost regulator. They don't extend battery life anywhere near as long as claimed and aren't very useful for modern devices that can tolerate low voltage, but they will bring nicads/NiMH up to alkaline levels, useful for fussy older devices. The downside is they will try to suck every joule out of the cell - not the best way to look after rechargeables. I believe they now have a version that cuts out at NiMH end voltage.
?
For PP3s, there are some lipo-based versions with a USB C charging port. These give full 9V, unlike earlier NiMH which were low voltage (though some had 7 cells instead of 6 to compensate). I've got a couple of these lithium ones and am so far pleased with them but haven't done a long-term test.
?
|
Re: Farewell Keysight Marketing.
This was done many years ago when there was some (small) benefit to Keysight.? When it started off, it hadn't achieved the peak of success it has today.? Much of the (clause 4J) I didn't know of. Naturally, when they waved a 3000 dollar oscilloscope at me, I just looked at my Tektronix 7904 and decided that I wouldn't buy. They've even stopped the "scope give away, which unaccountably never mentioned my name as a winner.
For some reason, if TEK does have a list, I never got on it.
I tend to either get equipment I can repair, or equipment that is essentially "use until breaks" and then if "cannot get the parts or fix it" then replace (if desirable).
Harvey
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On 9/6/2024 6:13 PM, Matt Harris wrote: People actually intentionally want to receive email spam to begin with?
|
dear Yves, I didn't realize that you had made the measurements expressly to help me! I owe you then a double (even triple) thanks! Especially considering the fact that the front end of this instrument is really very dense, complicated and delicate!
After my last email, in addition to doing the (essentially mechanical) intervention on the SYTF, I continued to check the input signal through the various sections by alternately injecting 300MHz @-20dBm and 5GHz @0 dBm
The signals were found to be in specification up to the A3A9 bandpass (where the two paths join to form the intermediate frequency of 321.4MHz). At this point I could see the 5GHz signal (converted), present at that point at -47dBm (the specification says -43/-56dBm).
Instead, no trace of the 300MHz input signal
Investigatine?the second converter A3A4 in more depth
I checked?the signals at its input
On J1 there is 3.9214GHz at -46dBm? --->OK
On J3 there is 321.4MHz @ -37.7dBm? --->OK
On J4 I did not check 600MHz @-1dBm but the fact that the converter works in band 1 tells me that the oscillator is present and is in specification
The power supply is quite OK (5V are actually 4.75; 10V are 9.98 and the DC that controls the internal switch that should be +15V? (band 0) and -3.5V?(band 1) is actually +14.60V and -1.35V
?
This last value is rather far from the nominal and would have worried me BUT band 1 is exactly the one that works
Conclusion: it would seem that the culprit is the second converter and in particular (probably) the internal switch that has the sole task of letting the signal? (which is already at 321.4MHz and does not need to be converted)?pass from its input to the output
In the next few days I will test the converter that meanwhile?has been?disassembled?; In the meantime I found a cheap one on the bay that should arrive in about ten days
Yves, I have a question: on the block diagram A3A4 is represented as a block that has 5 ports of which one (J5) would seem to be the connector that carries the power and the DC that controls the switch and that connects to A7 Analog Interface through the W35 cable
?
Actually,?this connector on the real component, does not have a name
Instead,?the name J5?, stamped on the case , indicates an SMB connector that has the writing LO TEST and in my analyzer?it is the one that?conveys the 600MHz LO signal?
Now,?on the block diagram the connector that conveys the 600MHz signal has the name J4 (in my analyzer, the J4 connector was disconnected)
?
This confusion of names and roles made me doubt that years ago, when I had disassembled this section I had not reassembled it correctly
thanks again and best regards
Adri
?
?
?
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----- Messaggio originale -----
Inviato: 06/09/2024 23:21:52
Oggetto: Re: [HP-Agilent-Keysight-equipment] HP 5086-7906 YTO
Hi Adri,
?
I had sent you the measurements of the RF input-output mixer signals verification, I had disassembled the High Frequency section of my 8595E to be able to provide you with this information.
If you have no more questions relating to this section, I will close my 8595E and do a flatness check to see if everything is correct.
?
Yves
?
?
thank you very much for all the suggestions and information with which I will continue my investigation
In the meantime I received the 2.5mm socket wrench and after?a little mod to adapt it?for the purpose (photo), I proceeded to align the spheres of the SYTF
I must say that the operation done under the microscope is quite simple
The nuts must be loosened (not too much) and with a small screwdriver that acts as a delicate lever, ?the supports of?the?spheres can be moved so that the coupling ring completely shadows them (i.e. the sphere is exactly in the center)
Removing the gold mesh was not necessary
The insertion loss has improved enormously:
at 5 GHz it is -6dBm at 6GHz it is -10dB (before the signal starting from this frequency was no longer visible) at 6.5 GHz it is only -3dB
I will install it when I have solved the problem of "blindness" in band 0 since the calibration constants that the instrument has in memory (in practice the tuning current data) are relative to the original SYTF and the "new" SYTW requires a? SYTF CAL is done
|
Re: HP 141T Power Supply Help Needed
Thanks for sharing that tip!? ? Will pick one up.? ??
I removed and reflowed the board yesterday.? Things changed slightly. Haven't had a chance to look at your last comments but i will get back to it tonight and report back?
Bill, ? A buddy of mine brought over his 141T and the -100V was missing and all of the small signal transistor were working OK but the pass transistor was not conducting.? I tapped the pass transistor and it started working¡? So I removed the two screws that hold the TO3 transistor in and it just about fell out of the socket.? It had ZERO insertion force!! The socket is bad which is a pain to get to but I pulled it out thinking I could squeeze the socket pins together and fix the problem, but the pins were so soft that after I put the transistor back in it still had almost no insertion force.? To make it reliable I have ordered some new sockets form Mouser. The are part number 4608 by Keystone Electronics for about $2.20 each.?? Hard to believe that the sockets are still available even if the 2N3055s and gone! ? Mike ? ? Bill, ? Since the driver is in saturation, Vce is almost 0V then it seems you may have a wiring problem.? Check the voltage across R40.? That should be about 22-24VDC.? If not check the voltage at C6 which is a big can lytic on top of the unit.? Also the wiring to and from the rectifiers CR1 and CR2.? The anodes of the two diodes should have about 24VAC. Or the fuse F4 is open.? There is not much left.? The error amp seems to be working.? Let me know what you find. ? Mike ? ? Mike,?
I now get a rather high impedance?at the output of the regulator, think it was ~50k.? ? ?The previous issue was in fact a physical short on A5 board (lead clipping...)
Currently, things look as follows:?
Q9
C .65?
B? 1.36
E .65
Q10?
C 2.4
B 0
E 0
Q11
C 1.3
B -.65
E 0?
Output Voltage -0.002
Output Impedance? ~400k? I get the sneaking suspicion that my driver is bad as the CE voltages are roughly equivalent (maybe .002 different).? ? ?The voltage I see at the base of Q9 seems close, so I'm guessing the sensor amp is working better..? ?Q10 base at 0v is a little weird.? ?
Like I say, I'll go back through things this afternoon and see if any remaining parts saw issues in the last round of testing.? ? ?This feels like progress though.? ? ?
I don't know how to fix Q4 socket long term, but I'm mulling that over.? I kind of want to insert / solder a pin in place of the spring contacts that have been causing me so much frustration.? ? ? ? On Thu, Sep 5, 2024 at 10:42?AM Michael Bafaro via <m.bafaro=[email protected]> wrote: Bill, ? The big question is what resistance do you measure at the pins of the A2 board that have the white / Violet wires going to them with the wires removed.? At this point you should read >1K Ohm at the output of the regulator.? If the resistance at the output of the regulator is < 4 Ohms don¡¯t put in a new pass device.? As I remember you had one of the white / violet wires that measured < 1 Ohm.? I seem to remember that you were going to trace out that wire to see where it went and why it read so low.? ?I remember you had one of the White / violet wires that went to the A5 assembly which runs the storage functions and you were going to find the cause of that later.? Let me know what you find. ? Mike ? ? Ugh, I put it down for a few days to work on an old Zenith my wife got for my birthday.? Today, I put a fresh pass trans in, and fired it up.? I got -2.5v for a few seconds and then it looks like it took out the transistor.? Replaced and same story.? ? ? Mike - with F4 removed, I measure ~50k ohm at the terminal you mention, so that rules out C9?? ? R49 does look ok..? my DMM only measures tenths, so I get a floating .2 to .3 ohm.? I guess I typo¡¯d the decimal or mentally transcribed wrong.. ?
Dave - I ran through each part you mention.? R44 was a little suspect in that the schematic says 20k but it measured 18k, still in range but I¡¯d have expected it to go UP. ? In a fit of rage, I replaced C8, C9 , R44, R46 and still blows pass trans.? ? ?Raw voltage in??is around 22v last I checked.
At this point, I¡¯m wondering if there is something under the board fighting me. ? It didn¡¯t look like I was the first person in here, and I¡¯ve been working from the top side only.? ? Is it worth pulling the board to look at? ? ? I could go eBay a bunch of old exotic parts, I could try to shotgun some moremodern parts in.. ? ? I do feel like I¡¯m loosing the battle on this rail though. ? Anyone in North Carolina?? :-)? ? Hello All
I have a hp 141t when it is powered up there is no trace but when I turn off the power the trace briefly appears in top right corner.
Is it the blanking circuit or do I need to do an trace? alignment or something else. I need some guidance
Has anyone encountered this problem before and let me know what you did.
73's Leroy de VK5HL
-----Original Message-----
From: [email protected] <[email protected]> On Behalf Of Chuck Harris
Sent: Tuesday, 3 September 2024 1:41 PM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] HP 141T Power Supply Help Needed
To amplify your comment, many times older linear supplies, when they are brute force recapped, with the best, long life, low esr caps you can find, will become beacons of chaotic oscillation.
I put a low ESR ceramic capacitor in the feedback loop of a unity gain OPAMP circuit the other day, and was amazed that it went totally unstable.? It was an older LM301 variety, where the response characteristics of the opamp are a blank slate until the designer adds in the stability network.? The designer's efforts were wiped out by my ceramic capacitor replacement for his 1uf back-to-back emulation of a non-polar electrolytic.
Sometimes the modern best replacement is not suitable for use in an older instrument.
-Chuck Harris
On Mon, 2 Sep 2024 22:40:20 +0100 "Dave_G0WBX via "
<g8kbvdave=[email protected]> wrote:
> Hi.
>
> It's just a generic term (damping is another) to slow down the
> response of a loop, to prevent it going unstable.
>
> Not an uncommon issue in some linear PSU's like those -12.6V or -100V
> regulator topologies that are not "conventionally" laid out.
>
> Unless you 'scope the thing, you often don't know it's gone unstable,
> other than some passive parts sometimes cook for no obvious reason.
> (That R49 for example!? See Mike's comment in another mail.)
>
> It is also not uncommon, when modern transistors are used to replace
> older failed parts (that are not available any more) and the new
> device has "a lot" more gain at HF than the originals, that regulator
> or other control loops suddenly become "unruly" under some operating
> conditions.
>
> Sometimes a low value "Base Stopper" resistor (a few Ohms, or a
> ferrite bead) in series with the new device's Base connection can
> restore sanity!
>
> Take care.
>
> Dave B.
>
>
>
|
Re: HP 141T Power Supply Help Needed
Bill, ? A buddy of mine brought over his 141T and the -100V was missing and all of the small signal transistor were working OK but the pass transistor was not conducting.? I tapped the pass transistor and it started working¡? So I removed the two screws that hold the TO3 transistor in and it just about fell out of the socket.? It had ZERO insertion force!! The socket is bad which is a pain to get to but I pulled it out thinking I could squeeze the socket pins together and fix the problem, but the pins were so soft that after I put the transistor back in it still had almost no insertion force.? To make it reliable I have ordered some new sockets form Mouser. The are part number 4608 by Keystone Electronics for about $2.20 each.?? Hard to believe that the sockets are still available even if the 2N3055s and gone! ? Mike ?
toggle quoted message
Show quoted text
From: [email protected] < [email protected]> On Behalf Of Michael Bafaro via groups.io Sent: Thursday, September 5, 2024 3:19 PM To: [email protected]Subject: Re: [HP-Agilent-Keysight-equipment] HP 141T Power Supply Help Needed ? Bill, ? Since the driver is in saturation, Vce is almost 0V then it seems you may have a wiring problem.? Check the voltage across R40.? That should be about 22-24VDC.? If not check the voltage at C6 which is a big can lytic on top of the unit.? Also the wiring to and from the rectifiers CR1 and CR2.? The anodes of the two diodes should have about 24VAC. Or the fuse F4 is open.? There is not much left.? The error amp seems to be working.? Let me know what you find. ? Mike ? ? Mike,?
I now get a rather high impedance?at the output of the regulator, think it was ~50k.? ? ?The previous issue was in fact a physical short on A5 board (lead clipping...)
Currently, things look as follows:?
Q9
C .65?
B? 1.36
E .65
Q10?
C 2.4
B 0
E 0
Q11
C 1.3
B -.65
E 0?
Output Voltage -0.002
Output Impedance? ~400k? I get the sneaking suspicion that my driver is bad as the CE voltages are roughly equivalent (maybe .002 different).? ? ?The voltage I see at the base of Q9 seems close, so I'm guessing the sensor amp is working better..? ?Q10 base at 0v is a little weird.? ?
Like I say, I'll go back through things this afternoon and see if any remaining parts saw issues in the last round of testing.? ? ?This feels like progress though.? ? ?
I don't know how to fix Q4 socket long term, but I'm mulling that over.? I kind of want to insert / solder a pin in place of the spring contacts that have been causing me so much frustration.? ? ? ? On Thu, Sep 5, 2024 at 10:42?AM Michael Bafaro via <m.bafaro=[email protected]> wrote: Bill, ? The big question is what resistance do you measure at the pins of the A2 board that have the white / Violet wires going to them with the wires removed.? At this point you should read >1K Ohm at the output of the regulator.? If the resistance at the output of the regulator is < 4 Ohms don¡¯t put in a new pass device.? As I remember you had one of the white / violet wires that measured < 1 Ohm.? I seem to remember that you were going to trace out that wire to see where it went and why it read so low.? ?I remember you had one of the White / violet wires that went to the A5 assembly which runs the storage functions and you were going to find the cause of that later.? Let me know what you find. ? Mike ? ? Ugh, I put it down for a few days to work on an old Zenith my wife got for my birthday.? Today, I put a fresh pass trans in, and fired it up.? I got -2.5v for a few seconds and then it looks like it took out the transistor.? Replaced and same story.? ? ? Mike - with F4 removed, I measure ~50k ohm at the terminal you mention, so that rules out C9?? ? R49 does look ok..? my DMM only measures tenths, so I get a floating .2 to .3 ohm.? I guess I typo¡¯d the decimal or mentally transcribed wrong.. ?
Dave - I ran through each part you mention.? R44 was a little suspect in that the schematic says 20k but it measured 18k, still in range but I¡¯d have expected it to go UP. ? In a fit of rage, I replaced C8, C9 , R44, R46 and still blows pass trans.? ? ?Raw voltage in??is around 22v last I checked.
At this point, I¡¯m wondering if there is something under the board fighting me. ? It didn¡¯t look like I was the first person in here, and I¡¯ve been working from the top side only.? ? Is it worth pulling the board to look at? ? ? I could go eBay a bunch of old exotic parts, I could try to shotgun some moremodern parts in.. ? ? I do feel like I¡¯m loosing the battle on this rail though. ? Anyone in North Carolina?? :-)? ? Hello All
I have a hp 141t when it is powered up there is no trace but when I turn off the power the trace briefly appears in top right corner.
Is it the blanking circuit or do I need to do an trace? alignment or something else. I need some guidance
Has anyone encountered this problem before and let me know what you did.
73's Leroy de VK5HL
-----Original Message-----
From: [email protected] <[email protected]> On Behalf Of Chuck Harris
Sent: Tuesday, 3 September 2024 1:41 PM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] HP 141T Power Supply Help Needed
To amplify your comment, many times older linear supplies, when they are brute force recapped, with the best, long life, low esr caps you can find, will become beacons of chaotic oscillation.
I put a low ESR ceramic capacitor in the feedback loop of a unity gain OPAMP circuit the other day, and was amazed that it went totally unstable.? It was an older LM301 variety, where the response characteristics of the opamp are a blank slate until the designer adds in the stability network.? The designer's efforts were wiped out by my ceramic capacitor replacement for his 1uf back-to-back emulation of a non-polar electrolytic.
Sometimes the modern best replacement is not suitable for use in an older instrument.
-Chuck Harris
On Mon, 2 Sep 2024 22:40:20 +0100 "Dave_G0WBX via "
<g8kbvdave=[email protected]> wrote:
> Hi.
>
> It's just a generic term (damping is another) to slow down the
> response of a loop, to prevent it going unstable.
>
> Not an uncommon issue in some linear PSU's like those -12.6V or -100V
> regulator topologies that are not "conventionally" laid out.
>
> Unless you 'scope the thing, you often don't know it's gone unstable,
> other than some passive parts sometimes cook for no obvious reason.
> (That R49 for example!? See Mike's comment in another mail.)
>
> It is also not uncommon, when modern transistors are used to replace
> older failed parts (that are not available any more) and the new
> device has "a lot" more gain at HF than the originals, that regulator
> or other control loops suddenly become "unruly" under some operating
> conditions.
>
> Sometimes a low value "Base Stopper" resistor (a few Ohms, or a
> ferrite bead) in series with the new device's Base connection can
> restore sanity!
>
> Take care.
>
> Dave B.
>
>
>
|
Re: Farewell Keysight Marketing.
Advertising has become the be all and end all of media of all types. Too much advertising. Much of it done badly, like bill boards. If you must look at one twice to get the message its a failure.
If not for advertising most print media, broadcasting, the internet would go away. Might be a good thing. Most graffiti is just advertising. When dogs mark their territory it amounts to advertising.
What does that have to do with electronic measurement?
My excuse is that its 111F here. Not advertising. The real thing.
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Show quoted text
On 9/6/2024 3:13 PM, Matt Harris wrote: People actually intentionally want to receive email spam to begin with?
--
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998
|
Re: 8566B attenuator removal
I did actually post pictures of what I was seeing on each of the settings on another related thread message #146621.? Having now taken a second look at those pictures however, I have noticed they were indeed at 1dB/div on the vertical scale so I shall have to re-do them on 10dB/div for the sake of clarity.
Sigh... Sunday I have some time available so will remove the attenuator and inspect its internals. I may post some photos of it's innards once that's been done.
I have to say I'm becoming rather more intimately acquainted with the guts of this analyzer than I'd ever imagined!
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Froggie the Gremlin
Frank Mashockie
Michael A. Terrell
Jinxie