Re: scanned: 545B and 561 Instrument Reference Books
A big THANX for all the effort !
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On Sat, Aug 11, 2018 at 8:27 PM Thomas Dodge <tdodge2404@...> wrote: Hi,
My name is Tom, and I haven't sent any emails in a while. I just bought a
Tektronix TDS 648A scope. I plugged it in for the first time, and all the
lights come on, but no intensity at all. Does anyone know how to approach
this issue? Thanks a lot.
Tom
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do you have anything points that you think will help in this process ?? Things to pay attention to. Only to be careful with the high voltage and the complex reassembly process. My replacement transformers were layer wound but the originals are pie (universal) wound. Chuck Harris on this group has wound beautifully made replacements for the 547 transformer that is similar but not identical. I don't know if he might be able to do a pair of 556 trannies. Good luck! Morris
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Re: SG 504 leveled sine wave generator.
Took the chance to recal. the unit using better precision gear than specified in the manual.
Improved the 6Mhz reference accuracy to -0.06dBm vs -0.12dBm with the R270 & R280 amplitude adjustments. Given the several connections from the new SMA leveling heads (adapters & 10dB attenuator to an N type power head). I'd guess the 0.06dBm loss is to be expected at 6Mhz.
All reference power levels are about spot on from 1Vpp thru 5Vpp now with the 6Mhz freq. Sometimes a little glitch helps u improve your instrument!
At the frequencies 245Mhz to 700Mhz I am seeing at most a 0.15dBm loss at 4Vpp thru those connectors, sometimes a bit less (freq dependent). The new Leveling head stub tuning offsets/negates the connector loss (by compensating upward) at the hi end of the range (1Ghz). So from about 700 Khz to 1Ghz the connector losses steadily diminish to nil.
8D
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Re: 2465B Replace Aluminum Electrolytics with Tantalum
And me 108 years.? That is if my electrolyics don't leak out.
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On ?Saturday?, ?August? ?11?, ?2018? ?09?:?07?:?45? ?PM? ?CDT, Leon Robinson <leon-robinson@...> wrote: Lets see that would make me 107 Years Young. Sounds like you did a good job.?Leon Robinson ?? K5JLR Political Correctness is a Political Disease. ? ? ? From: machineguy59 via Groups.Io <machineguy59@...> To: [email protected] Sent: Saturday, August 11, 2018 3:28 PM Subject: [TekScopes] 2465B Replace Aluminum Electrolytics with Tantalum ? See this photo album /g/TekScopes/album?id=66462 for my recent repairs on a 2465B.? This 2465B had modest corrosion on the A5 board from leaking aluminum electrolytic capacitors.? On this board the pads for C2222 and C2520 were partially eaten away and R2013 itself had failed completely (R2013 pads were OK).? A few cycles of applying flux, hot air heating, then wash with PCB cleaner and the board was ready for repair.? But I wanted a repair that did not suffer the same fate as the OEM assembly. Todays aluminum electrolytic capacitors have more robust seals than the ones Tek had available in the 1990's.? Also, hand soldering the capacitors to the board avoids severely heating the capacitor seals as happens with wave soldering systems.? Still, electrolytic capacitors always eventually fail and often leak electrolyte onto the PCB.? Tantalum electrolytics do not have this failure mode, at least not often, because they are made different.? So I resolved to replace the four aluminum electrolytic capacitors with SMD tantalum electrolytic capacitors.? I understand that Tektronix did something like that with certain 2465B scopes manufactured in Guernsey, UK (see here /g/TekScopes/photo/12841/0?p=Name,,,20,1,0,0 ). So I elongated one pad of each mounting for C2011, C2113, C2331, and C2965.? This was simple to do.? Each of these capacitors have a through hole or trace on one pad that can be cleaned and a copper foil strip can be soldered to elongate that pad by 1 to 2 mm (I was neat, not precise).? This allowed me to hand solder 2917 package size SMD capacitors.? I chose 4:1 or better voltage derating and an ESR of less than 1 Ohm in each case.? The result is working very well.? I will try to report back in 30 years on how the reliability turned out.
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SG 504 leveled sine wave generator.
Hi y'all:
Was doing some calibrations on some precision, stub tuned (+/- 0.10dBm @ 4Vpp, full range) leveling heads over the past couple of weeks for the EBAY sale listing that I put up occasionally when I have time.
The SG-504 plugin started to behave a bit wonky on the Hi band and I would have to change bands and power up and down a lot to get it to stabilize for a few mins.
Finally got out the extender cable and spent an hour on it checking around (hot/cold air/ tapping etc). Eventually managed to locate the problem as the Hi band current trimmer near the card edge connector. The wiper was intermittent.
Just an FYI if u see such behaviour in your units.
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Re: 2465B Replace Aluminum Electrolytics with Tantalum
Lets see that would make me 107 Years Young. Sounds like you did a good job.?Leon Robinson ?? K5JLR Political Correctness is a Political Disease. From: machineguy59 via Groups.Io <machineguy59@...> To: [email protected] Sent: Saturday, August 11, 2018 3:28 PM Subject: [TekScopes] 2465B Replace Aluminum Electrolytics with Tantalum See this photo album /g/TekScopes/album?id=66462 for my recent repairs on a 2465B.? This 2465B had modest corrosion on the A5 board from leaking aluminum electrolytic capacitors.? On this board the pads for C2222 and C2520 were partially eaten away and R2013 itself had failed completely (R2013 pads were OK).? A few cycles of applying flux, hot air heating, then wash with PCB cleaner and the board was ready for repair.? But I wanted a repair that did not suffer the same fate as the OEM assembly. Todays aluminum electrolytic capacitors have more robust seals than the ones Tek had available in the 1990's.? Also, hand soldering the capacitors to the board avoids severely heating the capacitor seals as happens with wave soldering systems.? Still, electrolytic capacitors always eventually fail and often leak electrolyte onto the PCB.? Tantalum electrolytics do not have this failure mode, at least not often, because they are made different.? So I resolved to replace the four aluminum electrolytic capacitors with SMD tantalum electrolytic capacitors.? I understand that Tektronix did something like that with certain 2465B scopes manufactured in Guernsey, UK (see here /g/TekScopes/photo/12841/0?p=Name,,,20,1,0,0 ). So I elongated one pad of each mounting for C2011, C2113, C2331, and C2965.? This was simple to do.? Each of these capacitors have a through hole or trace on one pad that can be cleaned and a copper foil strip can be soldered to elongate that pad by 1 to 2 mm (I was neat, not precise).? This allowed me to hand solder 2917 package size SMD capacitors.? I chose 4:1 or better voltage derating and an ESR of less than 1 Ohm in each case.? The result is working very well.? I will try to report back in 30 years on how the reliability turned out.
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2465B Replace Aluminum Electrolytics with Tantalum
See this photo album /g/TekScopes/album?id=66462 for my recent repairs on a 2465B. This 2465B had modest corrosion on the A5 board from leaking aluminum electrolytic capacitors. On this board the pads for C2222 and C2520 were partially eaten away and R2013 itself had failed completely (R2013 pads were OK). A few cycles of applying flux, hot air heating, then wash with PCB cleaner and the board was ready for repair. But I wanted a repair that did not suffer the same fate as the OEM assembly. Todays aluminum electrolytic capacitors have more robust seals than the ones Tek had available in the 1990's. Also, hand soldering the capacitors to the board avoids severely heating the capacitor seals as happens with wave soldering systems. Still, electrolytic capacitors always eventually fail and often leak electrolyte onto the PCB. Tantalum electrolytics do not have this failure mode, at least not often, because they are made different. So I resolved to replace the four aluminum electrolytic capacitors with SMD tantalum electrolytic capacitors. I understand that Tektronix did something like that with certain 2465B scopes manufactured in Guernsey, UK (see here /g/TekScopes/photo/12841/0?p=Name,,,20,1,0,0 ). So I elongated one pad of each mounting for C2011, C2113, C2331, and C2965. This was simple to do. Each of these capacitors have a through hole or trace on one pad that can be cleaned and a copper foil strip can be soldered to elongate that pad by 1 to 2 mm (I was neat, not precise). This allowed me to hand solder 2917 package size SMD capacitors. I chose 4:1 or better voltage derating and an ESR of less than 1 Ohm in each case. The result is working very well. I will try to report back in 30 years on how the reliability turned out.
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On Sat, Aug 11, 2018 at 05:29 PM, tom jobe wrote:
Hi Leo,
Yesterday I found the Fluke thermocouple and did some tests on a 2215A.
First I disconnected the optional fan, then let the scope run with two
traces like you did.
The temperature of the Mosfet Q9070 ceramic heat sink piece stabilized
at 54.0 degrees C in a 29.5 degree room.
I removed Q9070 and discovered it was a TP3N40 Mosfet that I doubt was
original, The only datasheet I found for it suggested that it was a 3
Amp part rated at 400 volts with an RDS(on) of 3.3 Ohms.
The Mosfet replacement I have used for years on 22xx's is the common
IRF840, so I put one of them in for Q9070.? According to the datasheet,
this is an 8 Amp 500 Volt part with an RDS(on) of 0.75 Ohms.
Later in the day, the 2215A stabilized with a temperature of 56.5
degrees in a 30 degree room.
Maybe I did not wait long enough the first time, because the results
were not quite what I expected?
In any case, I consider this 2215A to be functioning normally so this
range of Mosfet temperatures must be what we should expect to see.
I also believe that this 2215A has all of the standard component values
you would expect it to have for R909 etc.
tom jobe...
Hi Tom, I think we both see about the same temperatures, when I did my measurements it was around 32-33 degree Celsius in the room and mine ended at 59 Celsius (I really need aircon in there!!). The higher R-on FET does give a slightly higher temperature, but only like 2-3 degrees, so I think I'll wait for the fan to put in and call it a day. I like the 2215A for having the nice things like delayed timebase, and being light as well, in the future this will be my carry-on scope. That way I can leave the 2465B's and my TDS540B at home... :-) Thanks for filling in the blanks, Un saludo, Leo
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Hi Leo,
Yesterday I found the Fluke thermocouple and did some tests on a 2215A.
First I disconnected the optional fan, then let the scope run with two traces like you did.
The temperature of the Mosfet Q9070 ceramic heat sink piece stabilized at 54.0 degrees C in a 29.5 degree room.
I removed Q9070 and discovered it was a TP3N40 Mosfet that I doubt was original, The only datasheet I found for it suggested that it was a 3 Amp part rated at 400 volts with an RDS(on) of 3.3 Ohms.
The Mosfet replacement I have used for years on 22xx's is the common IRF840, so I put one of them in for Q9070.? According to the datasheet, this is an 8 Amp 500 Volt part with an RDS(on) of 0.75 Ohms.
Later in the day, the 2215A stabilized with a temperature of 56.5 degrees in a 30 degree room.
Maybe I did not wait long enough the first time, because the results were not quite what I expected?
In any case, I consider this 2215A to be functioning normally so this range of Mosfet temperatures must be what we should expect to see.
I also believe that this 2215A has all of the standard component values you would expect it to have for R909 etc.
tom jobe...
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On 8/10/2018 10:14 AM, satbeginner wrote: Hi all,
Hi Tom,
I tested for temperature this afternoon again, after I performed a full calibration on the scope.
So, the scope had been running for several hours when I did this measurement.
I used a 80-TK Fluke surface temperature probe, holding it flush with the small heatsink just next to the FET, that was the hottest spot I found.
At that point in time the scope was just running with both traces visible, where trace A was showing the "calibration" signal.
Hello Ed,
in the end I consider my modification of the PS minimal, I used a lower ON-resistance FET (better, but maybe a slightly higher "switch-on" current?), and I reduced the Gate series resistor, where Tek in some models removed it even completely. (maybe the faster current pulse is not filtered as it should be, so maybe some may be injected into the grid?)
In my humble opinion is adding a fan also in the category minimal, again, because Tek used several FAN configurations in basically the same Power Supply.
Hola Vincent,
I think even the 2-or 3-wire PC fans have electronics inside.
Usually these fans are brushless, so they need some form of rotating magnetic field, and this is generated by a cheap and simple oscillator and coil driving circuit.
Some information can be found here:
I added some pictures of the temperature taking in the album: /g/TekScopes/album?id=64919
Un saludo,
Leo
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Thanks for the info morrios , do you have anything points that you think will help in this process ??? Things to pay attention to.?
On Sat, Aug 11, 2018 at 5:22 AM, Morris Odell<vilgotch@...> wrote: I have uploaded scans of the hv transformer drawings to a folder in the Photos area called (not surprisingly) "556 high voltage transformers".
Good luck!
Morrios
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Re: scanned: 545B and 561 Instrument Reference Books
I don't currently have Instrument Reference Books for any instruments later than the early 1960s. If I find them, I will scan them and share the scans.
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On Fri, Aug 10, 2018 at 11:54 PM, <kickingypsy9@...> wrote:
hey all,i have a 464 with no crt display.front pannel lights work. i have the
service man..wow what a book ! Any comon problems causing crt not to light?
Are all the low voltages correct?
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I have uploaded scans of the hv transformer drawings to a folder in the Photos area called (not surprisingly) "556 high voltage transformers".
Good luck!
Morrios
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I have the Tek specification drawings for both the 556 HV transformers - I'm not sure if they're in the group files but if not I'll upload them.
When I mentioned a jig, what i was referring to was a test jig for the transformer to avoid the fiddly job of having to refit it into the box until it was working properly. It's necessary to make sure the rewound transformer is capable of withstanding the high voltages without arcing. To do that I lashed up the circuit on an old chassis I had lying around with the correct tube and other parts. I ran it from a suitable vacuum tube era bench power supply. I didn't include the feedback system. I just set it up to deliver roughly the correct output voltage by adjusting the oscillator screen voltage. When I was happy with it I reinstalled it into the box and replaced the PDA rectifier diodes with suitable fast high voltage silicon diodes which were not easy to find.
Of course it helps to be experienced in working with high voltage vacuum tube circuits and also to have a suitable power supply for testing. This is NOT a job for a newbie!!!!
Morris
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hey all,i have a 464 with no crt display.front pannel lights work. i have the service man..wow what a book ! Any comon problems causing crt not to light?
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Re: scanned: 545B and 561 Instrument Reference Books
I see you are very busy with the Reference Books Kurt so thanx for that. Are these books mainly about the "older" stuff from about the 1950 - 1960 era or made Tek them also for say the 547, 647a and 7000 series?
Ren¨¦ (and compliments for your perfect site, very informative!)
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Re: Tek 549 storage board anomaly
Could somebody forward this to the OP e-mail address, Tim Phillips (UK), please? Can't see it in the archives, as it's obfuscated by groups.io. Hopefully, at least the group moderators can see it, and also anyone saving his/her personal mailbox archive of this mailing list. Thanks in advance, Sebastian Sebastian Garcia wrote: Thanks. Here's rev. "PE" picture: /g/TekScopes/album?id=66032The technically-commented revision history should be in the IRB for the '549. Hopefully available in VintageTek's microfiche database. Thanks, Sebastian. Rajesh VS wrote: Thanks Sebastian, Interesting, Mine as well as the one Kurt posted back in 2008 have marking "PC" Both have (c) of 1965. Pics here - The one in Manual is PB,mine is PC, and what you have is PE, So I assume there is manual for later Revs and possibly a PD board too ? . . .
On Tue, Aug 7, 2018 at 12:32 AM, Sebastian Garcia <sg-listas@...>
wrote:
Thank you, Rajesh. Yes it seems so, as this one is #5202 (Portland
facilities).
The mod has been done in 1965, as both the board picture in the available
manuals and my physical board have printed "1965" in a copper/gold area.
The figure shows also the "PB" inscription, while this physical board
shows "PE". A revision version?
For reference, the mentioned picture is the following:
- (BAMA manual, S/N 1408) Fig. 4-16 in page 4-11 (with a typo in the
overlay label for R1185).
- (manoman.sqhill.com manual) Fig. 4-15 in page 4-10.
Both manuals are available on Kurt's site.
Regards,
Sebastian.
Rajesh VS wrote:
just for reference, I DO see R1185 in my 549, Scope Serial # - 001295.
May be the change happened in later Revs?
regds
Rajesh
. . .
On Mon, Aug 6, 2018 at 8:39 PM, Sebastian Garcia <sg-listas@...>
wrote:
Hi, I know this is an old post, but same puzzle here.
Trimpot R1185 and nearby flood-gate related components (appearing in the
available PDF manuals) aren't physically present in my storage board (dated
1965).
Any clues on the storage circuits evolution of this model?
Regards,
Sebastian.
Tim Phillips <tim@...> 06/20/10 #49860
from Tim P (UK)
I am trying to cal a 549 storage 'scope ser# 701529
The manual refers to FG cathode level R1195, but
on this instrument this pot does not exist. In fact
it appears to have never existed on this storage board
(dated 1965). Both my manual and the BAMA one show it
(sectn 6-45 and the schematic) There must be another
manual with a different cal procedure. Anyone have any
insights ?
many thanks (confused) Tim P
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(continued) typo, C4399 is at the +15V rail.
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Hi Tomas,
Since I was just curious what my 7704A would show I took off the upper side panels, attached probes and switched on the 7704A. A big very bright dot illuminated the center of the screen. At the same time smoke whirled up somewhere from the Hor Amp board! In hindsight I was glad that this happened with panels removed. A tantalum cap (C4399 at the +12V rail) was still hot. Replaced the cap and the scope was fine again.
I found no sign of 25 kHz ripple at TP41120 or in trace Intensity.
But I realized now that you monitored the TP via a plugin in your 7704A. What you see then is only the TP voltage when the sweep is running. You mis the voltage between sweeps (retrace etc.) since the CRT is blanked then. So you probably didn't notice that your plugin gets terribly overdriven by the TP signal. You discerned 2 mV ripple while the TP level varies a few volts between blanked and unblanked state! I think the ripple might be very well due to crosstalk with the plugin which is used to pickup the 25 kHz HV signal.
I started the same way but I new in advance that I should not increase the sensitivity that far. I repeated this with signal displayed at an other scope, only to be sure that both TP levels where in the dynamic input range of the external scope.
I must say that I had expected a larger 25 kHz signal from the 10X probe tip in the neighborhood of the HV box. Amplitude 50 mV or so at distance 1 cm from HV cable out location. But enough for stable triggering.
Albert
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On Mon, Jul 30, 2018 at 10:36 AM, Albert Otten wrote:
On Mon, Jul 30, 2018 at 05:33 AM, Tomas Alori wrote:
While triggering on the CRT cable signal (to make the dotting stand still) I
checked TP41120 (with the other Vert plugin) and I could see ripple of 2mV
that aligns exactly with the dotting. Is 2mV enough to cause this?
BTW, the circuit is making a irregular crackling sound. It does not match
the
dotting though.
A few volts change is needed at TP41120 in order to vary the trace brightness
from just visible to normal. So 2 mV is nothing in my opinion. You might
simply verify this. Vary the Intensity control and note the TP level shifts
and brightness changes. (I think the Intensity control is far too coarse to
obtain 2 mV shift!).
It's likely now that the fault is somewhere in the HV circuits, including the
grid voltage level shifter. Not the easiest problem to solve.
Albert
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Ancel
satbeginner