The Minisert is re-born - at least in concept
<https://www.mill-max.com/products/new/zero-profile-press-fit-receptacles> ? Cheers, David ?
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Re: 2465B - Replaced RIFAs and now won't POST
Hi? When I was 16, (74 years ago ) I worked on a US schematic to build a power amplifier,? 2 feedback capacitors electrlytics were designed in wrong polarity . connected between the tubes plates ..400 V and? cathodes close to ground. It did work some time,
but eventually there was an explosion... And the amp cease working.? Just because the cap of the electrolytic was thrown away and its connecting wire short circuited the Hi Volt to ground..
Do not try to connect lmytics inverted...!
Jean? L? C? Ruelle
Bobert29,
My thought is you need to check the plug connectors on the side of the A2A1 board J121 and J122 as you might be one pin off from connector to board.? These plug connectors are not easy to see when plugging connector to the board.
Craig
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Re: 2465B - Replaced RIFAs and now won't POST
Bobert29,
My thought is you need to check the plug connectors on the side of the A2A1 board J121 and J122 as you might be one pin off from connector to board. These plug connectors are not easy to see when plugging connector to the board.
Craig
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Re: 2465B - Replaced RIFAs and now won't POST
Have you worked on one of these before??
?
ISTR that there's a misprint on the silk screen showing a supply filter cap in the wrong orientation...
I know someone who recapped his 2445B and it didn't work after that - I have it in my stack of things to fix... Quite likely a problem with a board interconnect...
?
...which reminds me: The 2465B PSU has fragile interconnecting pins - Are they all ok??
?
?
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2465B - Replaced RIFAs and now won't POST
2465B
s/n 57xxx
When I first powered it up, the lights would all come on for a split second, then they would go out, then it would cycle through the self-tests, failing at TEST 05, so I cleaned up the A5 corrosion and replaced a few components there. I also replaced the RIFAs on the power supply.
Following that, when I turn it on, the lights all come on, but they don't go out.
All J119 points are well within spec. I am a little confused at times when following the service manual, for example the troubleshooting procedure said TP201 should be +10v, but the schematic seems to indicate it should be +5v, which is what I'm getting.
I'm not sure how to proceed at this point. I'd like to go as far as possible before I am forced to buy a new oscilloscope to repair this one.
Thanks
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Re: 2465B nonlinear sweep
Read the little notes below the table for that sweep speed calibration.
There is some compromise required at the highest sweep speeds.
Also, what makes you think any substitute for U800 is going to work
exactly like a real U800? The calibration is "tuned" to deal with the
vagaries of the real deal.
-Chuck Harris
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Show quoted text
On Sun, 20 Apr 2025 11:43:53 -0700 "Keith" <keith@...> wrote: I've recapped a 2465B and replaced a faulty U800 with a RU800, ran
through cal OK except for one thing. It seems that at fast sweep
speeds e.g. 5ns, the X axis is distorted appearing compressed to the
far right of the waveform. You can see an image here (100MHz sine
wave applied to Ch1) :
Has anyone seen anything like this, or have an idea what may be
causing it?
- Keith
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I've recapped a 2465B and replaced a faulty U800 with a RU800, ran through cal OK except for one thing. It seems that at fast sweep speeds e.g. 5ns, the X axis is distorted appearing compressed to the far right of the waveform. You can see an image here (100MHz sine wave applied to Ch1) :
?
?
Has anyone seen anything like this, or have an idea what may be causing it?
?
- Keith
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Re: T801 HV transformer winding
Chuck Harris used to do do it. Very long and complex ....Think he no longer does it.
Search Chuck's posts for 2465/465/475576/577 rewind high voltage transformers
Also see tekscopes. and EEV blog
j
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Re: Tektronix TDS754D - failing acquisition module tests
All,
I'm doing a bit of regrouping on this repair pursuit, and wondering if anyone possibly has the order of the channels as laid on the acquisition board for this scope handy (top of board, where the demux chips are). I'm certain I've seen a thread or a post somewhere about this, but I can't track it down right now for some reason. I also want to avoid possible differences between A10 revisions, etc., as much as possible. Going by just PIPE-A through PIPE-D (as per 520B SM), assuming A = CH1, it seems to me U200 demux would serve CH3, and is the second from the left, as one looks at the board from the top having the wide connectors side of A10 also on their left. But maybe it's not as simple and my assumption above is incorrect.?
Thank you,
Radu.
On Sat, Mar 22, 2025, 5:41 PM Radu Bogdan Dicher via <vondicher= [email protected]> wrote: To answer some possible questions, I've reflowed the U200 solder joints, to eliminate the possibility there's one or more "cold" ones.?
On Sat, Mar 22, 2025 at 5:39?PM Radu Dicher < vondicher@...> wrote: Jared and all, I finally managed to make this work with my GPIB solution.? The error seems to be:
"SAT MAR 22 17:19:35 2025 ?ERROR: diagnostic test failure, digDataFormatDiag, ?ERROR!!BYTE mode, in demux 200 ,i= 4 memBaseAdr 0x738000a= ?data = fffffa00, expectedData[i] = aa00"
I wonder if anyone can shed some light into this error, and whether it seems to point to anything useful for troubleshooting. This is the only error standing, apparently.?
On Mon, Mar 10, 2025 at 5:42?PM Radu Bogdan Dicher via <vondicher= [email protected]> wrote: That makes perfect sense, thank you, Jared. I assume, once I recover my adapter (just realized it's currently?on loan), I need to run the commands via Python (the only way I know).? Radu.?
The scope doesn't care what GPIB adapter you use, if it works on other gear, it'll work on the scope.
?
You only need the specific National Instruments GPIB card for running the Tektronix calibration software.
?
All other GPIB functions can be done with any working GPIB adapter.
?
?
?
Jared.
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Re: horz output FETs in 2245?
On Wednesday (04/09/2025 at 02:14PM +0100), David C. Partridge via groups.io wrote: Boca Semi have the VN1316N2, Little Diode have the VP0116N2
Both listed on eBay. Yes. I have ordered VN1316N2 from Boca for a grand total of $33.xx after taxes and tips. After a few days, they still have not shipped so hoping they are a legit seller. PS Check driver circuits before replacing - don't want to blow replacement
parts when they average about $20 apiece. Yes. Have done so. Thank you. Everything appears good right up to that N-channel device. Was hoping to find someone who has tried a modern part in there but that seems to be uncharted territory. Also, very difficult to find modern parts with low gate capacitance. These original parts are in the 25 to 35pF range but new stuff is 10 or 100x that. Interesting. In any case, thanks for the reply! Chris -----Original Message-----
From: [email protected] <[email protected]> On Behalf Of Chris
Elmquist via groups.io
Sent: 07 April 2025 16:37
To: [email protected]
Subject: [TekScopes2] horz output FETs in 2245?
I sent this the other day to the other TekScopes list but thought I would
try here too for more ideas.
I was given a 2245 recently which of course doesn't work too well.
Investigation reveals that Q805 and Q806, in the horizontal right plate
output stage, are cold to the touch.
The service manual, section 6.2 (page 6-19) says,
The MOSFET output transistors (Q801 and Q802 left plate-- Q805 and
Q806 right plate) run hot. If either side is cold, it is defective.
So, that's me and now I need to find a couple of these VDMOS FETs, which
seem to have become quite rare.
They are Tek P/N,
151-1211 VN1316N2 N-Channel VDMOS FET, 160V, 250mA, 40 ohm
151-1212 VP0116N2 P-Channel VDMOS FET, 160V, 250mA, 25 ohm
Has anyone solved this problem with a modern replacement pair? and have
suggested substitutes? These are in TO-39 package which adds additional
challenge but I suppose TO-220 or equiv could be made to fit. Of course,
the real thing would be great too if there is a source.
Thanks for any leads!
Chris
--
Chris Elmquist
-- Chris Elmquist
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Re: horz output FETs in 2245?
Boca Semi have the VN1316N2, Little Diode have the VP0116N2
Both listed on eBay.
PS Check driver circuits before replacing - don't want to blow replacement
parts when they average about $20 apiece.
HtH
David
toggle quoted message
Show quoted text
-----Original Message----- From: [email protected] < [email protected]> On Behalf Of Chris Elmquist via groups.io Sent: 07 April 2025 16:37 To: [email protected]Subject: [TekScopes2] horz output FETs in 2245? I sent this the other day to the other TekScopes list but thought I would try here too for more ideas. I was given a 2245 recently which of course doesn't work too well. Investigation reveals that Q805 and Q806, in the horizontal right plate output stage, are cold to the touch. The service manual, section 6.2 (page 6-19) says, The MOSFET output transistors (Q801 and Q802 left plate-- Q805 and Q806 right plate) run hot. If either side is cold, it is defective. So, that's me and now I need to find a couple of these VDMOS FETs, which seem to have become quite rare. They are Tek P/N, 151-1211 VN1316N2 N-Channel VDMOS FET, 160V, 250mA, 40 ohm 151-1212 VP0116N2 P-Channel VDMOS FET, 160V, 250mA, 25 ohm Has anyone solved this problem with a modern replacement pair? and have suggested substitutes? These are in TO-39 package which adds additional challenge but I suppose TO-220 or equiv could be made to fit. Of course, the real thing would be great too if there is a source. Thanks for any leads! Chris -- Chris Elmquist
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T801 HV transformer winding
Hi, Anyone know someone who can rewind HV transformers? Lost my beams on my 561.
Thanks?
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horz output FETs in 2245?
I sent this the other day to the other TekScopes list but thought I would
try here too for more ideas.
I was given a 2245 recently which of course doesn't work too well.
Investigation reveals that Q805 and Q806, in the horizontal right plate
output stage, are cold to the touch.
The service manual, section 6.2 (page 6-19) says,
The MOSFET output transistors (Q801 and Q802 left plate-- Q805 and
Q806 right plate) run hot. If either side is cold, it is defective.
So, that's me and now I need to find a couple of these VDMOS FETs, which
seem to have become quite rare.
They are Tek P/N,
151-1211 VN1316N2 N-Channel VDMOS FET, 160V, 250mA, 40 ohm
151-1212 VP0116N2 P-Channel VDMOS FET, 160V, 250mA, 25 ohm
Has anyone solved this problem with a modern replacement pair? and have
suggested substitutes? These are in TO-39 package which adds additional
challenge but I suppose TO-220 or equiv could be made to fit. Of course,
the real thing would be great too if there is a source.
Thanks for any leads!
Chris
--
Chris Elmquist
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Tektronix and HP Catalogues Available
I am still cleaning up and ran across a 1980 Tektronix Catalog, a 1981 Tektronix Catalog, a 1980 HP Catalog, and a 1981 HP Catalog.? All are hard covers.? The are free if you pay the shipping costs although I would gladly accept and appreciate donations!
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Re: Tek 492 SA PSU removaal
Back in the day...? While I was working at Tek UK (Maidenhead.)
The first 492 that came into the UK was unpacked by Sales for a
demo, and instantly blown up!
Those early units were 115V input only...? While the UK was 240V
mains!
So (no pressure of course) with no manual, figured out how to get
inside, remove the PSU, stripped it down, found the dead parts,
and traced the input circuit, converted it from full wave doubler,
to full wave rectifier (one trace cut, from memory.)
Replaced the Diodes, Fuse, and power FET'setc in the primary
switching side, and gently wound it up on a Variac.? Some strange
noises (no load) but no fire or brimstone either.? Checked some
secondary voltages, that seemed to be "safe", so powered down, and
re-assembled it all.
It powered up fine* and worked without issues.
(*No such thing as PAT testing then, if the ELCB(RCD) on the
bench didn't trip, it was good to go!)
Shortly after, it was in the back of a car on it's way to a major
UK customer for demo/evaluation, who eventually bought several of
them...
(A "Portable" microwave SA?? Only if you were built like Arnie,
and even then you'd end up with one arm longer than the other!??
Good instruments for what they were capable of in a "portable"
form factor back then.)
Did I get any kudos for that "emergency repair"??? Of course
not.?? The first of many such events working for a string US based
companies in the UK, when I bailed out sales or similar...? I
never learnt!
The 492P appeared a few days before before I left.
I still sometimes come across a 492 (as well as other Tek kit of
that era, I was there for 3 years) still sporting stickers,
showing my initials...? Never gets me any discount though!
73.
Dave. "DJB"
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Re: Tek 492 SA PSU removaal
James thanks for your RIFA warning
They tend to fail on 240v mains, we are 120v here.
This 492 was unused for 20 years and in great shape
Thus I leave it for now as it's working fine, but should rework the PS sometime
Looking for a front cover and printed service manual as I am very bad with PDFs
Have an absolutely fantastic day
Jon
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Re: Tek 492 SA PSU removaal
Change the Rifas as they WILL blow.
? I've worked on a few of these PSU's and they are very reliable, however many/most are 40+ years old now and need some TLC.
?Do you have BOTH manuals??
If not I'll post the 2nd one (with the PSU details) into the archives.
?Good luck?
?
James
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Re: Tektronix TDS754D - failing acquisition module tests
To answer some possible questions, I've reflowed the U200 solder joints, to eliminate the possibility there's one or more "cold" ones.?
On Sat, Mar 22, 2025 at 5:39?PM Radu Dicher < vondicher@...> wrote: Jared and all, I finally managed to make this work with my GPIB solution.? The error seems to be:
"SAT MAR 22 17:19:35 2025 ?ERROR: diagnostic test failure, digDataFormatDiag, ?ERROR!!BYTE mode, in demux 200 ,i= 4 memBaseAdr 0x738000a= ?data = fffffa00, expectedData[i] = aa00"
I wonder if anyone can shed some light into this error, and whether it seems to point to anything useful for troubleshooting. This is the only error standing, apparently.?
On Mon, Mar 10, 2025 at 5:42?PM Radu Bogdan Dicher via <vondicher= [email protected]> wrote: That makes perfect sense, thank you, Jared. I assume, once I recover my adapter (just realized it's currently?on loan), I need to run the commands via Python (the only way I know).? Radu.?
The scope doesn't care what GPIB adapter you use, if it works on other gear, it'll work on the scope.
?
You only need the specific National Instruments GPIB card for running the Tektronix calibration software.
?
All other GPIB functions can be done with any working GPIB adapter.
?
?
?
Jared.
|
Re: Tektronix TDS754D - failing acquisition module tests
Jared and all, I finally managed to make this work with my GPIB solution.? The error seems to be:
"SAT MAR 22 17:19:35 2025 ?ERROR: diagnostic test failure, digDataFormatDiag, ?ERROR!!BYTE mode, in demux 200 ,i= 4 memBaseAdr 0x738000a= ?data = fffffa00, expectedData[i] = aa00"
I wonder if anyone can shed some light into this error, and whether it seems to point to anything useful for troubleshooting. This is the only error standing, apparently.?
On Mon, Mar 10, 2025 at 5:42?PM Radu Bogdan Dicher via <vondicher= [email protected]> wrote: That makes perfect sense, thank you, Jared. I assume, once I recover my adapter (just realized it's currently?on loan), I need to run the commands via Python (the only way I know).? Radu.?
The scope doesn't care what GPIB adapter you use, if it works on other gear, it'll work on the scope.
?
You only need the specific National Instruments GPIB card for running the Tektronix calibration software.
?
All other GPIB functions can be done with any working GPIB adapter.
?
?
?
Jared.
|
Re: [TekScopes] 7934 Service Manual
Bob,
Yes, thank you. I see that I concluded that it doesn't have sections 8 and 9 because I was looking at the end of the PDF, which are the Change Information pages. I do see the duplicate pages.
Without a copy of the original manual (or an original manual itself) I can't tell what else might be incorrect with the online copies. Since many of the pages of the online copies are partial pages, I'd have to compare the pages in the online PDFs to an original manual. Perhaps someone out there could do that, but since the 7934 is pretty rare, I doubt that there is anyone who is paying attention to this thread who will do that.
I have sent pp. 31, 6-22 and 6-23 to Mark, the OP. That will have to suffice, for now. I may upload my revised PDF that contains those three missing pages. I can scan my original that is a later revision, but that will take a lot of time due to the fold-out pages.
DaveD
KC0WJN
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Show quoted text
On 3/22/2025 9:16 AM, mst3krules via groups.io wrote: The copy I look at came from this link:
Part No. 070-5880-00
MANUAL Product Group No. 42
First Printing May 1986
It has what I assume is section 8, which isn't numbered, then section 9 followed by a section of Manual Change Information then the duplicate pages.
Bob
--
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David C. Partridge
Craig Cramb
Bobert29
Froggie the Gremlin
James55