Re: 1S1 sampling unit; (also 7B53AN & 7A18 plugins)
I was given an old 547 that was set for scrapping. It that had some high
voltage issue. The tubes were partially pulled but it seems intact
otherwise.
I'm located in Austin Tx if anyone wants to come pick it up.
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EDN Article: FG502 Repair
I did a search and somehow this one slipped through the net:
FG502 Teardown and Repair by Paul Rako, mis-titled ¡°...FG503....¡±
Shaun M.
<>
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Re: TDS3054 Replacement of DALLAS DS1742W (U640), data content in NV-RAM
Look up " james_s <>" on EEVBLOG. He has a much better solution. i would show you a picture, but I don't know how in here. On Sun, Aug 30, 2020 at 12:23 PM maddisassembler < 320041677522-0001@...> wrote: Hello all,
a TDS3054 (built in year 2001) shows the following symptoms when connected
to power:
- 'A system error has occured', Error Count =11, 'display error', goes
away after short power off/on
- Unrealistic high 'total operation time' (16350105 hours)
- Impossible time setting (e.g. '11:80:21')
Topic #157465 also deals with this issue, the problem is data corruption
inside
U640 DALLAS DS1742W, exhausted lithium battery, date code on the
package is '0029'.
I ordered replacement DS1742W via Amazon in China (the chips I received
seem fully functional when
tested on a programmer), date code on the package is '0945'.
How should I prepare the new DS1742W I am going to install in the scope?
Simply read out the (most probably) rubbish of the old DS1742W and copy
it to the new one?
Is a memory map available somewhere which shows the addresses of the
relevant memory locations and their expected content in a working scope?
(the address locations 0x7F8...0x7FF are described in the DS1742W data
sheet)
I cannot believe that appr. 2k of memory are fully used to store internal
scope
status data.
Thanks for any help!
Best regards
-Roland
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On Tue, Sep 1, 2020 at 03:39 PM, teamlarryohio wrote:
BTW, they're right below the RPR directory
Don't know where "right below.." is. I've taken the liberty to introduce the term "Replaceable Parts Registry" on Tekwiki for those who don't know the term "RPR" (yet). Both terms give ahit now. Raymond
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Re: Strange Tek2440 issue
On Tue, Sep 1, 2020 at 10:04 AM Siggi via groups.io <siggi= [email protected]> wrote: On Mon, Aug 31, 2020 at 8:36 PM Vince Vielhaber <vev@...> wrote:
The 5V jumping around is the 5V regulated that C494 is on. There it
drops a volt or so when I switch below 200ns. According to my Fluke,
when it goes out completely it holds at 3.93v.
Oh, interesting. I assumed you were talking about the 5VD, which is the
main switch-mode regulated supply that feeds all the digital logic.
You're talking about the linear regulated 5V supply. Same deal though, go
back to the first decoupling cap, see whether the supply is jaggy and
whether the raw supply holds up when the regulated supply drops. Most
likely - as others have noted - this is due to geriatric bulk caps in the
secondary, so check that first.
If the raw supply is holding up OK when the regulated supply drops, then
you move downstream and see what's up. This supply is current limited, so
you can infer the current it's using by measuring across the shunt.
Incidentally I'm not finding a power distribution diagram in the service manual. Looking at schematic <10>, though, you'll see that the peak detectors and the CCD arrays run on the +-5V linear regulated supplies, so that'd explain why one or both of those is getting dragged low when the sampling speed is jacked up.
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Re: Strange Tek2440 issue
On Mon, Aug 31, 2020 at 8:36 PM Vince Vielhaber <vev@...> wrote: The 5V jumping around is the 5V regulated that C494 is on. There it
drops a volt or so when I switch below 200ns. According to my Fluke,
when it goes out completely it holds at 3.93v.
Oh, interesting. I assumed you were talking about the 5VD, which is the main switch-mode regulated supply that feeds all the digital logic. You're talking about the linear regulated 5V supply. Same deal though, go back to the first decoupling cap, see whether the supply is jaggy and whether the raw supply holds up when the regulated supply drops. Most likely - as others have noted - this is due to geriatric bulk caps in the secondary, so check that first. If the raw supply is holding up OK when the regulated supply drops, then you move downstream and see what's up. This supply is current limited, so you can infer the current it's using by measuring across the shunt.
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Per Dave Brown: That's the purpose of the common parts catalogs of which we also got >a release and are posted on TekWiki. I don't know if they all are there >but they can be scanned and uploaded. They've served me well for around 40 years. There are more of them up on the wiki than we had in the service center. BTW, they're right below the RPR directory. -ls-
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Re: 1S1 sampling unit; (also 7B53AN & 7A18 plugins)
I wouldn't even think of interfacing the 1S1 with anything other than a 530,540.550 series Tek scope. It's a complex interface, involving not just the connector but several different power supplies ranging from 6.3 volts up to 500 volts. The plugin also has to sink 150 mA at 75 volts from the mainframe. The differential output of the plugin has a 67 volt common mode component that matches the input requirement of the 500 series Tek vertical amplifiers. Some of the 540/550 series also had a sync interface. The only thing you can do is keep your eyes peeled for a suitable mainframe. The most desirable one IMHO is the 547 although it is prone to the HV transformer thermal runaway problem. The 535A which does not have that problem would be the next best.
Good Luck!
Morris
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Re: Tek 7854 intermittent issues
Still refuses to do any AQS's at all. You probably tried AQS because I pointed to that. Something very strange is going on with AQS in my 7854 (or with my brains?) AQS worked at 0.5 ms/div but not at 0.2 ms/div and faster. OK. Later on I thought to remember a trick to mislead the scope: set trigger level for not triggering, then do AQS (the scope waits...), then switch to faster sweep rate, then turn trigger level produce a sweep. Somehow it didn't work, error all the time. I switched off the scope and read the operators guide. AQS: works ONLY with 7B87! But I used a 7B80 (no 7B87 at all in the scope). And AQS just worked fine at 0.5 ms/div. Back to the 7854 to do it once more. And this time AQS gave an error beep all the time!?? I have a 7B87 but didn't succeed to AQS a waveform with gaps. The manual says that "empty" horizontal locations are filled with the last valid data at the left side, so not by interpolation between two valid data points. I did notice though
that during an AVG acquisition (when the issue was active) if I already have
it in digital mode. I could actually see it missing chunks as it gets data and
then just filling it in with weird stuff at the end, making those slopes and
spikes (badly trying to interpolate the missing sections of the wave?) *see
first video for alright example.
[this one: Broken video: ] Very nice video. Indeed seems to show interpolation afterwards. .... when I tapped on the transistors in the
horizontal section, suddenly it worked just fine! You might "jiggle" circuit boards and connectors as well, who knows...
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Re: Tek 7854 intermittent issues
No pictures this time but, (YET AGAIN) it's changed behavior, now its getting AVG acquisitions (mostly) fine (As in not erroring out but still occasionally having some weird defects to the wave but now everything is the right size and, mostly intact). Still refuses to do any AQS's at all. I did notice though that during an AVG acquisition (when the issue was active) if I already have it in digital mode. I could actually see it missing chunks as it gets data and then just filling it in with weird stuff at the end, making those slopes and spikes (badly trying to interpolate the missing sections of the wave?) *see first video for alright example.
Never mind, in the middle of writing this I turned on the scope to check ( sat for a few hours powered off ) and it was doing it again, but I've discovered something very strange that may have solved (at least a small part of and temporarily) the mystery of this thing when I tapped on the transistors in the horizontal section, suddenly it worked just fine! This thing is weird, doesn't make much sense to me as they aren't even the metal potted ones but the ones in the heat sink clamps. Luckily I took some video this time, first before the miraculous (and likely temporary) fix and again when it started making proper acquisitions. Still won't do AQS under any settings though.
Broken video:
Working video: (flashing on analog side is from a dirty pot I'm fairly sure)
Also Dave, you are definitely right about which transistor that is, thank you for finding it for me. According to my service manual A17Q141 to be exact . Although Q141 (and it's paired Q41) are PNPs ( tek part no.151-0220-00 ) but I can't really find any other specs than some incomplete ones I scraped together, having some difficulty locating an equivalent replacement if case I need it, but I may just be bad at looking (don't know if you can fudge the numbers a bit like some caps)
Tomorrow, if I have time after work, I'll finally check the power supply and see if it's correct or not. Sorry if this was a little rambly, I should have called it a night hours ago.
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Re: Strange Tek2440 issue
Hi,
I would first check the power supply. I'm not a big fan of "the universal
internet method of fixing everything", that is indiscriminately recapping
stuff, but in the case of the 24xx family DSOs, I had 3 of those and all
had practically every cap failed in the PSU. So a complete replacement of
capacitors at the secondary side is one thing I would do first at the
slightest suspicion of power problems.
Szabolcs
Vince Vielhaber <vev@...> ezt ¨ªrta (id?pont: 2020. aug. 31., H,
20:04):
toggle quoted message
Show quoted text
Acquisition stopped, doesn't happen. I can go all the way to 2ns/div.
Normal trigger but trigger set to +or- 90v (not triggering), it happens.
Single, doesn't happen, can go all the way to 2ns/div, can even trigger
it (in single) and it doesn't happen. The probe was hooked to the
calibrator for the triggers. Normally doesn't matter if there's a
signal there or not.
Thanks!
Vince.
On 08/31/2020 01:43 PM, Siggi wrote:
Hey Vince,
I have no idea what's going on there, though I'd suggest looking at the
power supplies as a first step.
You can also - perhaps - diagnose this a little ways by playing with
trigger and acquisition settings. My guess would be that a power supply is
collapsing when the sample clock exceeds some particular rate, though
that's of course just a guess.
Does this still occur when the acquisition is stopped? If not, you can
maybe narrow this down by e.g. going to NORM sweep/trigger mode, and
setting up a trigger that never hits. Does it still happen when acquisition
is started but no trigger fires? How about under a single-shot acquisition
in AUTO mode, etc.
Siggi
On Sun, Aug 30, 2020 at 5:37 PM Vince Vielhaber <vev@...> wrote:
I picked up a 2440 on ebay that had the dead nvram battery problem. Got
that fixed up with an external battery. Ran thru the self cal and ext
cal and all seems fine, except when the sweep rate is turned above 100
or 200 ns.
In trying to research this a bit, the only thing I could find was on one
of the Tek forums back in 2017 but there were zero responses. Here is
how the other person described the problem:
---------------------------------------------------------------------
The 5 volt regulated rail is getting crowbared when the scope Sec/Div is
set to 100ns or faster. If save is pressed at a slower setting the
Sec/Div can then be set to any value without the 5 Volt rail getting
pulled down. It appears the issue only occurs during an active
acquisition cycle at 100ns Sec/Div or faster.
----------------------------------------------------------------------
While I didn't measure the 5v rail, the screen shrinks a couple of times
as the waveform changes, the inputs get switched to GND and the display
goes blank. Sometimes, if I'm quick enough, I can turn the sweep back
down (1us or slower) and it'll recover, but I still have to go to the
input coupling and switch the inputs off of GND.
Anyone seen this or have any ideas what's going on?
Thanks!
Vince.
--
K8ZW
--
K8ZW
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That's true when looking for Tek part numbers. The added value of OCR here would be *reverse* use: "What's the Tek no. of a 2N4275?" That's the purpose of the common parts catalogs of which we also got a release and are posted on TekWiki. I don't know if they all are there but they can be scanned and uploaded. Dave
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Re: 1S1 sampling unit; (also 7B53AN & 7A18 plugins)
The 1S1 is a fine sampler when it works. It is however what I would call "high strung". It has a way of failing in interesting and completely different ways all the time.
It is also not easy to troubleshoot because of the feedback loops and complex sequence of events.
You could keep an eye out for this
Then you could also power up the four times faster and also more reliable 1S2 should you find one.
Maybe you already know the 1S1 has a 50 ohm input, keep an eye out for these fun accessories:
800MHz+ active probe
TDR pulser add-on
Hi-Z probe adapter
Somebody, I don't know who (but he smells good), bought all of these things the picosecond they hit eBay so they are more expensive now.
These things are all over half a century old now so they are brittle and stinky and probably don't work.
But they are fun!
You can also start here and build your own adapter
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Re: Strange Tek2440 issue
F269 is soldered but I was able to clip onto L256. A minor amount of ripple that only changed by a few millivolts when I added a 2200uf cap across it. No change when I switch below 200ns.
The 5V jumping around is the 5V regulated that C494 is on. There it drops a volt or so when I switch below 200ns. According to my Fluke, when it goes out completely it holds at 3.93v.
The 10v reference that divided and sent to U870B is solid.
Thanks!
Vince.
toggle quoted message
Show quoted text
On 08/31/2020 06:43 PM, Siggi wrote: Hey Vince,
My bet would be that if you go back to the 5VD supply, you'll find that
C455 and/or C262 are shot. CR354 is also a suspect, but the bulk caps on
the 5VD supply are the primaries. If you can find a way to look at the
supply before L256, I betcha you're going to find it all jaggy and
disgusting.
If you have a way to measure the two capacitors, that'd work too. Assuming
F269 is not soldered in, you can pretty much isolate the two capacitors by
popping it out.
Good luck,
Siggi
On Mon, Aug 31, 2020 at 6:23 PM Vince Vielhaber <vev@...> wrote:
Yep, I have a 2430A and a couple of 11402s. I used the 2430A.
I checked the + and -5 and the + and -15 volt rails. Sure enough, the
+5 volt rail drops exactly 1 volt while it's happening.
I'm thinking, would piggybacking another 5 volt source on that rail
isolate if it's the power supply or something else?
Thanks!
Vince.
On 08/31/2020 05:09 PM, Siggi wrote:
On Mon, Aug 31, 2020 at 2:04 PM Vince Vielhaber <vev@...> wrote:
Acquisition stopped, doesn't happen. I can go all the way to 2ns/div.
Normal trigger but trigger set to +or- 90v (not triggering), it happens.
Single, doesn't happen, can go all the way to 2ns/div, can even trigger
it (in single) and it doesn't happen. The probe was hooked to the
calibrator for the triggers. Normally doesn't matter if there's a
signal there or not.
Interesting. I'd look at the power supplies, should be easy enough to see
what's happening as this is reproducible. Do you have a second digital or
storage scope to look at what's happening on the power rails?
The only difference between single shot and run without trigger is that the
single shot capture has a very limited duration. Maybe the problem is that
a power rail is marginal, and so gets dragged down when the CCDs & capture
clock keep running for a while.
Once you start capturing the CCDs start storing (and discarding) the
signal, waiting for a trigger.
--
K8ZW
--
K8ZW
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Re: 1S1 sampling unit; (also 7B53AN & 7A18 plugins)
On Tue, Sep 1, 2020 at 01:26 AM, David Collier wrote:
Forgot to mention I have TEK TAS465; HP1640A and Hantek 200MHz digital
available as test gear.
Isn't that an HP 1740A 'scope? Didn't see a 'reply' icon previously, no idea why not.
You won't see the Reply icon unless logged in. Raymond
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Hi Dave, My comments embedded On Tue, Sep 1, 2020 at 01:46 AM, Dave Brown wrote:
I am of the minority opinion here. The file is linear. You grab the scroll bar
and scroll to where you need to be. For me it's quick.
That's true when looking for Tek part numbers. The added value of OCR here would be *reverse* use: "What's the Tek no. of a 2N4275?" Unless the reverse list is available. I'm just waiting for someone to post an OCR'd/searchable file.
I was trying to find out if posting such file was acceptable, see my earlier messages. I would like to copy and paste a couple of pages and see how well it matches the RPR.
The OCR'ed pages don't look different from the original because the searchable text normally is invisible "behind" the normally visible level. Believe me, I tried different tools and the accuracy was absolutely awful. My opinion
is that a false search is worse than no search, hence the lack of OCR. I don't
think microfiched 132 column computer printout works all that well for this
purpose.
After looking further into my results this evening I have to agree with you, unfortunately.
Tektronix gave the museum a release. I personally spent 80+ hours scanning
these documents and put a lot of care into them. I have an OCR version of the
670 RPR. Here's what the part numbers look like when I copy and paste to see
what's really there..
670-0070-01
67o-oo71-00
67(R)07~:.:oo
670-0073-00
:67(R)07S~tr
A full search of this document is taking a very long time and it will never
find 670-0071-00. Your mileage may vary. I chose to use the scroll bar as it
is faster and accurate. Somebody prove me wrong. I'd like to know what tool
you used that gave accurate results.
As I wrote above, my results have on further study shown to be quite disappointing as well. A certain category of items, like module numbers, serial number groups etc. were pretty successful but that's not what the effort was for. Searches on e.g. a JEDEC number are far less successful and that's what I would consider an important benefit. Obviously, I didn't try "looking for" Tek numbers, because that's not what would be interesting: Simple scrolling gets you there. That is never what OCR'ing is about. It is for searches like the example I gave above. It is my impression that the discussion in this thread has been hampered by misunderstanding of what was to be achieved: Smaller files, OCR and if so, for what purpose. Especially the latter two have caused confusion. It turns out that OCR'ing the available files does not produce satisfactory results, as stated early during the discussion. That aspect was confused with why one would want it at all. Raymond
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I am of the minority opinion here. The file is linear. You grab the scroll bar and scroll to where you need to be. For me it's quick.
I'm just waiting for someone to post an OCR'd/searchable file. I would like to copy and paste a couple of pages and see how well it matches the RPR. Believe me, I tried different tools and the accuracy was absolutely awful. My opinion is that a false search is worse than no search, hence the lack of OCR. I don't think microfiched 132 column computer printout works all that well for this purpose.
Tektronix gave the museum a release. I personally spent 80+ hours scanning these documents and put a lot of care into them. I have an OCR version of the 670 RPR. Here's what the part numbers look like when I copy and paste to see what's really there..
670-0070-01
67o-oo71-00
67(R)07~:.:oo
670-0073-00
:67(R)07S~tr
A full search of this document is taking a very long time and it will never find 670-0071-00. Your mileage may vary. I chose to use the scroll bar as it is faster and accurate. Somebody prove me wrong. I'd like to know what tool you used that gave accurate results.
Dave
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Re: 1S1 sampling unit; (also 7B53AN & 7A18 plugins)
Thanks all for advice. Yes would love to get a 500-series TEK! A 535 (?) in particular, just before the multi-tubed Y amp version.
Forgot to mention I have TEK TAS465; HP1640A and Hantek 200MHz digital available as test gear.
Didn't see a 'reply' icon previously, no idea why not.
Valves (tubes) keep you warm in the winter.
Regards
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Re: Strange Tek2440 issue
Hey Vince,
My bet would be that if you go back to the 5VD supply, you'll find that
C455 and/or C262 are shot. CR354 is also a suspect, but the bulk caps on
the 5VD supply are the primaries. If you can find a way to look at the
supply before L256, I betcha you're going to find it all jaggy and
disgusting.
If you have a way to measure the two capacitors, that'd work too. Assuming
F269 is not soldered in, you can pretty much isolate the two capacitors by
popping it out.
Good luck,
Siggi
toggle quoted message
Show quoted text
On Mon, Aug 31, 2020 at 6:23 PM Vince Vielhaber <vev@...> wrote: Yep, I have a 2430A and a couple of 11402s. I used the 2430A.
I checked the + and -5 and the + and -15 volt rails. Sure enough, the
+5 volt rail drops exactly 1 volt while it's happening.
I'm thinking, would piggybacking another 5 volt source on that rail
isolate if it's the power supply or something else?
Thanks!
Vince.
On 08/31/2020 05:09 PM, Siggi wrote:
On Mon, Aug 31, 2020 at 2:04 PM Vince Vielhaber <vev@...> wrote:
Acquisition stopped, doesn't happen. I can go all the way to 2ns/div.
Normal trigger but trigger set to +or- 90v (not triggering), it happens.
Single, doesn't happen, can go all the way to 2ns/div, can even trigger
it (in single) and it doesn't happen. The probe was hooked to the
calibrator for the triggers. Normally doesn't matter if there's a
signal there or not.
Interesting. I'd look at the power supplies, should be easy enough to see
what's happening as this is reproducible. Do you have a second digital or
storage scope to look at what's happening on the power rails?
The only difference between single shot and run without trigger is that the
single shot capture has a very limited duration. Maybe the problem is that
a power rail is marginal, and so gets dragged down when the CCDs & capture
clock keep running for a while.
Once you start capturing the CCDs start storing (and discarding) the
signal, waiting for a trigger.
--
K8ZW
|
On Mon, Aug 31, 2020 at 11:03 PM, zenith5106 wrote:
Yes absolutely, it's the same one. Off course I had to unlock it first but
reference to VintageTek is still s?there.
I use an old Adobe Acrobat 9 Pro and bookmarking isn't that much work, it may
have taken me less than 30 minutes.
Hi H?kan, Thanks for allowing me to look into your file. I don't think both are the same scan. I'll PM you re. this. Re. bookmarking: You're using it to create a TOC, which can be as limited or extensive as you want. I like your choice. A search function after OCR'ing provides functionality a bit like a cross reference. Every search takes the role of an entry into an xref-table, which can be many thousands. In this document it would e.g. allow finding the Tek number for a particular JEDEC transistor, like a 2N4275. Can be very handy if a JEDEC-to-Tek list isn't available. Unfortunately, I found both your and my OCR result lacking, as expected and mentioned by others in this thread. Raymond Raymond
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Shaun M
Raymond Domp Frank