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Re: Thoughts on upgraded(?) replacement parts for vintage equipment

 

I fully agree.? Though it is slightly OT, comes to my mind the nice display replacement card for the Tek DC508 frequency counter.? Else these nice units would not be usable any more as these old LED display are all slowly dying.
?
73 from Claude VA2 HDD
?
?
Re: Agilent 34461A schenmatic

 

¿ªÔÆÌåÓý

Thank you Jared.

I don't know how helpful photos will be unless they clearly show the manufacturer part number, but it's certainly worth a try.

From: [email protected] <[email protected]> on behalf of Jared Cabot via groups.io <jaredcabot@...>
Sent: Sunday, October 6, 2024 10:49 PM
To: [email protected] <[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] Agilent 34461A schenmatic
?
I'll take photos from my 34461A when I get home from work if you like?
?
?
Jared
Re: Agilent 34461A schenmatic

 

Ok, I am used to FB for ferrite beads; E is a new one on me.? ?I'm a professional EE working on airborne military radar subsystems for Raytheon at the moment. The 34416A DMMs are leased and belong to the program (government).? No way am I going to risk voiding warranty or calibration.? ? Jim


On Sun, Oct 6, 2024 at 9:49 PM, Jared Cabot via groups.io
<jaredcabot@...> wrote:
I'll take photos from my 34461A when I get home from work if you like?
?
?
Jared
Re: Boonton 92BD Troubleshooting Cataract

 

I'm in northern AL and would be more than willing to help if possible - and I'm sure that there are many others in the group that would as well.? As Steve suggested, if you could give at least a general geographic area then hopefully someone will step up and offer assistance.
?
Hal
?
Re: Boonton 92BD Troubleshooting Cataract

 

On 2024-10-07 7:58 AM, Michael A. Terrell wrote:
The VA is to do mine. I want iit, but I've been unable to find anyone willing to spend an entire day with me. The VA wo't do the surgery without an escort, because of the need for sedation.
Where are you located, and where's the facility?

Steve Hendrix
(ex USAF myself...)
Re: 8131A Error F500

 

That's good!? If the error is on the transducer board, that board has no ASICs.? Just some transistor arrays that could be hard to find these days.? But there are ways around that.??
?
?
Re: Thoughts on upgraded(?) replacement parts for vintage equipment

 

DaveD & Michael - you both pretty much mirror my feelings on it.? The 5087A is the reason that it has been on my mind lately since it is a current work in progress.? I currently have 7 of them that I have accumulated over the years and, of course,? only enough cards to fully populate 4, which will be sold. My plan is to use my own designs in two of them as I am looking for functionality first and the cool HP case is just a bonus; I'm currently using a Brandywine FDA-1050 as my main distribution amplifier and it will be replaced by the HP units and sold.? I've done several iterations of the output amplifier and divide-by-2/5 cards just trying different approaches for fun and seeing how much I can better the original performance. High hopes for the batch coming in - I went fully modern with the designs and not only is the BOM cheaper, hopefully the HD numbers are quite a bit lower.? Only one design each for the divider and the output amplifier - just install different values L&C for the filter section as well as a jumper for the divider.? I did not do any of the multiplication cards as they are just not something that would ever be used (and I already have a couple of each just in case.)? I did do a pretty much exact copy of the input amplifier just for giggles - I already have a *ton* of the originals.? I did the PS board as well, also just for fun - same design, just moved the bulk filter cap to the board itself and used a DIP-14 package for the reg.? The end result of this, for me, is two fully populated units with only one original card (the input card) in each.? Nicely functional but hardly "original."??
?
Hal
?
Re: Boonton 92BD Troubleshooting Cataract

 

The VA is to do mine. I want iit, but I've been unable to find anyone willing to spend an entire day with me. The VA wo't do the surgery without an escort, because of the need for sedation. I've worn glases for over 60 years and even then I couldn't deal with tiny things. I currently use a 24" monitor, wih 28 point font and sit about four inches from it. I have a decent Loupe to bring things into better focus, but I can't do any troubleshooting like this. Sadly, I was the one who took care o a lot of other Veterans to make sure they received treatment, ut I'm the only one left.

I had an off last year, but I couldn't make the trip at that time. I'm in my 70s as well, and have several other issues.I appologize for the off topic continuation of this thread.


On Mon, Oct 7, 2024 at 7:45?AM Mike Feher via <n4fs=[email protected]> wrote:

This is off topic, but I figured most of us are probably in the same age group and will have to face cataract surgery. I am 79 and had one eye done on April 1st and the other on the 15th. You can get the special lenses, but insurance will not cover them. I opted for the special lenses at $3K per eye. Getting those means you essentially will never need glasses for anything. Since I did not need glasses previously, I decided I did not want to start now. I am amazed. It is like I now have completely new eyes. The colors are all vivid and small print is no problem. So, if any of you are on the fence about it, go for it. 73 ¨C Mike

?

Mike B. Feher, N4FS

89 Arnold Blvd.

Howell NJ 07731

908-902-3831

?

From: [email protected] <[email protected]> On Behalf Of Michael A. Terrell
Sent: Monday, October 7, 2024 3:55 AM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] Boonton 92BD Troubleshooting

?

I have? one 42B and three 92B? that I plan on doing this to, after my Cataract surgery.? I will leave a note inside each describing the modification, and the reason for it. I've moved on tho the 4200 & 9200 meters I used a 9200 at Microdyne to read the -3dB points on Sallen=Key video filters, along with a HP3325A These replaced a tunable Wavetch function generator? and an analog meter. I could? get it to the exact? point. Foe lower frequencies I used a Floke 8920A Digital True RMS voltmeter.? I miss being able to work. This was top of the line Telemetry equipment for the Aerospace industry.

?

I would love to find a source for the two pin sensor cables. I have a 250 foot spool of SVHS video cable that will be perfect, since it has two coaxial cables in it.

?


Virus-free.
Re: Boonton 92BD Troubleshooting Cataract

 

¿ªÔÆÌåÓý

This is off topic, but I figured most of us are probably in the same age group and will have to face cataract surgery. I am 79 and had one eye done on April 1st and the other on the 15th. You can get the special lenses, but insurance will not cover them. I opted for the special lenses at $3K per eye. Getting those means you essentially will never need glasses for anything. Since I did not need glasses previously, I decided I did not want to start now. I am amazed. It is like I now have completely new eyes. The colors are all vivid and small print is no problem. So, if any of you are on the fence about it, go for it. 73 ¨C Mike

?

Mike B. Feher, N4FS

89 Arnold Blvd.

Howell NJ 07731

908-902-3831

?

From: [email protected] <[email protected]> On Behalf Of Michael A. Terrell
Sent: Monday, October 7, 2024 3:55 AM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] Boonton 92BD Troubleshooting

?

I have? one 42B and three 92B? that I plan on doing this to, after my Cataract surgery.? I will leave a note inside each describing the modification, and the reason for it. I've moved on tho the 4200 & 9200 meters I used a 9200 at Microdyne to read the -3dB points on Sallen=Key video filters, along with a HP3325A These replaced a tunable Wavetch function generator? and an analog meter. I could? get it to the exact? point. Foe lower frequencies I used a Floke 8920A Digital True RMS voltmeter.? I miss being able to work. This was top of the line Telemetry equipment for the Aerospace industry.

?

I would love to find a source for the two pin sensor cables. I have a 250 foot spool of SVHS video cable that will be perfect, since it has two coaxial cables in it.

?


Virus-free.
Re: Thoughts on upgraded(?) replacement parts for vintage equipment

 

I've had to scrap equipment with a physically? damaged board that? I couldn't locate a replacement for. The ability to drop in a new board for a reasonable price would keep a lot more old equipment in service.

On Mon, Oct 7, 2024 at 5:37?AM Harold Foster via <halfoster=[email protected]> wrote:
The current thread on the Boonton 92BD had a reference to someone having developed a modern replacement for the chopper amplifier portion of the instrument.? Others, including myself, have made replacements for all of the cards in a HP 3400A and I am currently awaiting a complete set or redesigned cards for the HP5087A - including the power supply, just because, and there are many more instances where replacements have been made simply because of unobtanium parts.? My question is: how do modifications such as this affect your feelings about the instrument?? At what point is it "just not the same" in a philosophical sense I suppose? For me if it's something that I have designed and made myself then that goes a long way to offsetting the lack of originality, especially if it enables the use of equipment that would otherwise have to be parted out.? Anyway, just some idle thoughts while waiting on the caffeine to kick in...
?
Hal
Re: Thoughts on upgraded(?) replacement parts for vintage equipment

 

¿ªÔÆÌåÓý

Many vintage units had limitations based on the available technology at the time that they were designed. For the most part, GenRad, HP and Tektronix (to name just three) built the most advanced instruments they were able to at the time.?

One of the great things about those vintage instruments is that they are repairable (a la Jim Williams). In my opinion, creating replacement PWBs and other improvements make the instruments more useful. The notion of extending their useful life time is an excellent idea and worth the effort. Just my 25 cents (inflation).

DaveD
KC0WJN

Thanks for all the fish.
==============================
All spelling mistakes are the responsibilty of the reader (Rick Renz, STK, ca. 1994)
==============================

On Oct 7, 2024, at 05:37, Harold Foster via groups.io <halfoster@...> wrote:

?
The current thread on the Boonton 92BD had a reference to someone having developed a modern replacement for the chopper amplifier portion of the instrument.? Others, including myself, have made replacements for all of the cards in a HP 3400A and I am currently awaiting a complete set or redesigned cards for the HP5087A - including the power supply, just because, and there are many more instances where replacements have been made simply because of unobtanium parts.? My question is: how do modifications such as this affect your feelings about the instrument?? At what point is it "just not the same" in a philosophical sense I suppose? For me if it's something that I have designed and made myself then that goes a long way to offsetting the lack of originality, especially if it enables the use of equipment that would otherwise have to be parted out.? Anyway, just some idle thoughts while waiting on the caffeine to kick in...
?
Hal
Re: 8131A Error F500

 

Managed to have a brief look at these over the weekend. Looks like I do indeed have two faulty output boards (both channel 1) and one good one (channel 2) I was sure I had tested the output board from unit 1 in a good unit and it worked, but maybe I made some error.?
?
Looking at the self test flow diagram in the manual this this makes sense, X04 error can only occur if the input to the transducer board is correct, but the output is wrong.? The manual suggests checking the transducer board pins, be nice if it was that simple. Will have further look when I get chance.?
Thoughts on upgraded(?) replacement parts for vintage equipment

 

The current thread on the Boonton 92BD had a reference to someone having developed a modern replacement for the chopper amplifier portion of the instrument.? Others, including myself, have made replacements for all of the cards in a HP 3400A and I am currently awaiting a complete set or redesigned cards for the HP5087A - including the power supply, just because, and there are many more instances where replacements have been made simply because of unobtanium parts.? My question is: how do modifications such as this affect your feelings about the instrument?? At what point is it "just not the same" in a philosophical sense I suppose? For me if it's something that I have designed and made myself then that goes a long way to offsetting the lack of originality, especially if it enables the use of equipment that would otherwise have to be parted out.? Anyway, just some idle thoughts while waiting on the caffeine to kick in...
?
Hal
Re: Boonton 92BD Troubleshooting

 

I have? one 42B and three 92B? that I plan on doing this to, after my Cataract surgery.? I will leave a note inside each describing the modification, and the reason for it. I've moved on tho the 4200 & 9200 meters I used a 9200 at Microdyne to read the -3dB points on Sallen=Key video filters, along with a HP3325A These replaced a tunable Wavetch function generator? and an analog meter. I could? get it to the exact? point. Foe lower frequencies I used a Floke 8920A Digital True RMS voltmeter.? I miss being able to work. This was top of the line Telemetry equipment for the Aerospace industry.

I would love to find a source for the two pin sensor cables. I have a 250 foot spool of SVHS video cable that will be perfect, since it has two coaxial cables in it.


On Sat, Oct 5, 2024 at 7:13?PM Bill Berzinskas via <bberzinskas=[email protected]> wrote:
Michael, at least one person has modified this unit to use a solid state differential amp.? He built a new plug-in card and it's definitely on the table for me, just haven't looked enough into it.??

Thank you for the feedback!! ?

On Sat, Oct 5, 2024, 6:37?PM Michael A. Terrell via <terrell.michael.a=[email protected]> wrote:
I currently have very poor vision, so I missed tat part. I've had eye problems my whole life, but I now have cataracts and hav? been unable to have the surgery. These units have fa outlived their design life and the chopper is always suspect because the lamps weren't rated for a very long useful life. I would add a sub board with the modern circuit, rather than mess with reusig badlt aged lamps., but that choice is yours. I repaired equipment for? daily use in production, along with my opersoal shop.? so the equipment had to meet all specifications at outr in house Metrology lab. I prefer to repair a fault, just once. My work centered on testing and calibrating boards made in house for our products, but I ofteny worked with the lab to find was to repair equipment that there were few or no spare parts.

On Sat, Oct 5, 2024 at 3:30?PM Bill Berzinskas via <bberzinskas=[email protected]> wrote:
@Michael T -
I mentioned that the recorder port is presenting 13.5v always, so there may be something there to look at.? ?If i remove either the chopper or shaping amp boards, it returns to zero.??
This is why it leads me to believe the digital part is ok, its just passing around signals from further up in the chain, i assume.? ? Will dig into it further, still digesting the schematic and manual, tracing through what i can when i have time.? ?

I do think the chopper is passing through to the board and into the circuit but i'm not seeing anything coming OUT of it into the shaping amp, might be the opamp on the output side, tbd.? ?

Either way, I'll cross post to the other group if I get a chance today.??


@Curt, mines the opposite and pined on the high stop.? ?One thing that's driving me mad, the only subsection of the block diagram besides the actual board labels is the lone word "chopper".? I'd love to understand more specifically WHERE the attenuator, 2nd amplifier, sync detector actually reside.? ??


On Sat, Oct 5, 2024 at 3:21?PM Curt Helstrom via <cahelstrom=[email protected]> wrote:
I have repaired two 92B's with this technique.? It appears that as the choppers age, their timing effects the meter's operation (both of mine
showed meter pined to the negative stop).? What I did was to swap the cathodes of CR207 and CR213, that is I connected CR207 cathode to
the original connection point of the CR213 cathode and vis versa, connected the cathode of CR213 to the original connection point of CR207.
?
This changes the timing of when the synchronous detector measures the signals coming from the chopper through the amplifiers, and compensates
for the delays caused by an aging chopper.
?
As mentioned, I've repaired two 92B's with this technique, both meeting all specifications after this modification.
?
Hope this helps in your efforts to repair your meter.
Re: Agilent 34461A schenmatic

 

I'll take photos from my 34461A when I get home from work if you like?
?
?
Jared
Re: Boonton 92BD Troubleshooting

 

I have a 92B in case you need somebody to poke at parts and give you some readings.
Re: 8665B noisy signal & Cal Errors

 

I have an 8644B which had power supply issues when I purchased it as a non-working auction off at e-site. I traced it to bad connections around the connectors for the power supply. Removing the power connectors where plugs into the motherboard, cleaning good with contact cleaner, and reinstalling seem to clean that up. After that, I discovered a bad frac-n card, which I was able to find rather cheaply. It works pretty good after fixing all these issues, but I usually use the 8663A due to its crystal clean signal. Anyway, I seem to remember seeing that exact same type of thing on mine, and cleaning that molex type connector fixed it. I think HP ended up putting just a bit more current through that connector then there should be, causing problems years later. Hopefully your unit will be just as easy to fix.?
Re: Anyone able to do GC or GC-MS on Hp ThinkJet Black ink ( for the Hp ThinkJet 2225 printer; Hp 9226a Or Hp 51604a ink cartridges ) ?

 

Ed,

Just a warning about the ET-3850. I have one. It's lovely but it does
try to reach the cloud all the time (yuck) and it does have a waste
cartridge. So despite the marketing hype the only waste tank free
printer I own is the HP 2225A. I have yet to need to reset the counter
for my waste cartridge but as I understand it that software is
proprietary. There are sketchy 3rd party flashing tools to do all this
but it gives me the creeps not being able to see what is going on
under the hood. Ironic if you think about it, I went from an open 1st
gen inkjet to a closed product that is advertised as "open".

-Evan

On Sun, Oct 6, 2024 at 9:23?PM ed breya via groups.io
<eb@...> wrote:

Yup, I switched to lasers long ago, mono and color - Brother brand is my favorite. I wouldn't get another inkjet except for something like the Epson ECOtank 3850, with the bottled inks. At least the ink is cheap enough to keep going for a long time despite the waste on head cleaning. I had this one for about a year or two, then gave it to my sister for her art work in need of photo-grade printing, and for heavy document use by her friend for work. It's great for all that, but not so much for sporadic use.

I was going to get another next time it was on sale at Costco, but in the meantime picked up a huge few-year-old HP color laser, then decided that was plenty enough for me, and skipped the Epson. I can always get one if really needed. I actually do have one older inkjet, for emergency use only. About ten or fifteen years ago, these little printers were kind of promo/giveaways like when you bought a new PC, so I saved several over the years, but never opened the inks or used the printers until emergencies came up. Then each got used up as much as possible, then junked out and recycled as soon as it had any print problems. I'm down to my last one, maybe ten years old, sitting on the shelf like new with its instructions, SW install CD, USB cable, and cartridges.

Anyway, I respect inkjets for their simplicity and amazing printing capabilities, but not so much their practicality or lifespan. I've junked out dozens of these and lasers too over decades, so have seen lots of innards of both elegant and crappy designs, and everything in between.

Ed


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Re: Agilent 34461A schenmatic

 

E usually designates a ferrite bead in my experience.? At least I've seen HP manuals do this.
?
Also, Jim what do you do for work that you would get in trouble for opening up your equipment?? Hopefully not a repair tech? Just curious.
?
-Frank
Re: Agilent 34461A schenmatic

 

¿ªÔÆÌåÓý

These appear to be ferrite chokes.
Value may not be overly important.
Usually used to pass DC and reduce RF on a line.

Glenn
WB4UIV

On 10/6/2024 9:39 PM, Jim Ford wrote:
Sorry I couldn't be of much help, Keith.? Say, now I'm curious, what kind of components do those E reference designators stand for?? The only time I've seen that used was at Powerwave (now out of business) where they were solder connection points for coaxial cables.? Are those ferrite beads or something?? Enquiring minds want to know!???? Jim

On Sunday, October 6, 2024 at 08:02:49 PM CDT, Yves Tardif <yves_tardif@...> wrote:


Hi Keith,

?

This is some pictures from my 34465A.

?

Yves

De?: [email protected] <[email protected]> De la part de Keith Harvey
·¡²Ô±¹´Ç²â¨¦?: 6 octobre 2024 10:04
??: [email protected]
Objet?: Re: [HP-Agilent-Keysight-equipment] Agilent 34461A schenmatic

?

Hi Jim,

?

Thank you for the insight and offer to assist.

?

The unit I have has some burned components on the main PCB.

If I send a list of the silkscreen component designations, can you open one up and determine the manufacturer part numbers?

?

I'm one of those people who refuses to pay an outrageous sum to replace the entire board when a few dollars of replaceable components are the only thing necessary to make the device functional, again.

?

Just in case you are able and willing to do this, I've included the component designations:

?

CR1008

E1005

Q1003

U1005

E1002

?

I've also attached pictures of the locations of these components.

?

BTW: "No" is an acceptable response.

?

Regards,

Keith Harvey

?

From: [email protected] <[email protected]> on behalf of Jim Ford <james.ford@...>
Sent: Saturday, October 5, 2024 4:56 PM
To: [email protected] <[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] Agilent 34461A schenmatic

?

Keith, that one is probably too new to have a schematic available.? Blame the suits at HPAK and everywhere else for that.? BTW, we have several of the 34461A DMMs around Raytheon where I work, so if you have a question about how to operate it, or is it supposed to do this, or whatever, I'm happy to check it out on one of the ones at work.? HTH.

?

Jim Ford

Laguna Hills

California

USA

?

On Saturday, October 5, 2024 at 03:41:04 PM CDT, Keith Harvey <keithh534@...> wrote:

?

?

Greetings,

?

Does anyone know where I might obtain a full schematic for the Agilent 34461A?

?

TIA,

Keith Harvey


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