Thanks Harvey,
I just read your email. The self test did actually work one, but only
after cycling the power on and off a few times. When I powered it on the
other day, the panel lights came on, but I didn't hear the relays activate,
and no self test ran. I think the first time i powered in on, and cycled it
on and off a few times, it was working ok. Thanks again for your help. It
really is a great scope.
Tom Dodge
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On Mon, Jan 11, 2021 at 4:56 PM Harvey White <madyn@...> wrote: I'm not in California, in fact, about as far away in the US as you can
get from there.
However, I've worked a bit on TDSS540 scopes, and I have a TDS640 as well.
Things to know:
1) the only high voltage is in two places, inside the power supply
(should be more or less shielded), and inside the monitor (should be
shielded as well).
Most other voltages are at the class 2 (less than 24 or so volts) level.
2) these power supplies are similar, but not as well documented as you'd
like. It sounds a bit like a power supply problem until you check all
the voltages and know it isn't.
3) some scopes of the era (and type) have a known capacitor problem.
Try inspecting each capacitor on the boards (not the PS board, that's
another animal) for dull looking leads or any sign of leakage. I'd
suggest that you look for threads about the TDS series which will cover
various issues about some capacitors. There's a self test capability (at
least in mine) on the CPU board which runs through a number of tests,
with the pass/fail indication being on a 7 segment readout. It should
hang (with the right switch settings) on a failing test. That'll give
you an idea if the CPU is failing.
Further than this, I can't help too much, there are people here who have
done a lot more work on these than I have.
Harvey
On 1/11/2021 7:19 PM, Thomas Dodge wrote:
Hi,
I emailed about this before. I have a Tektronix TDS 684A scope, and it is
in very good condition, and it was almost working, but now it is not. I
bought it from a surplus place, and I had seen it every time I came into
the place. When I took it home the first time, and powered it on, it didn't
do anything. But after a while, the panel lights came on, and it did run
the self test. When I powered it on recently, the panel lights power on,
but no self test at all. I want to know how to fix this. I do have the
manual, but I would like to work together with someone who is local in my
area who is more experienced than I am. I could just send it off to be
repaired, but that would be no fun for me. I have a couple other Tektronix
scopes that are not working too. Does anyone know who is around my area? I
am in California, in the San Gabriel Valley area in Glendora. I want to
learn how to fix these when problems come up. I am well aware of the high
voltage that is present here, so that's why I am asking. Any help is
appreciated. Thanks very much.
Thomas Dodge
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Re: 2mV and 5mV ranges read the same on 2236
Jeff,
If the vertical pre-amp is designed similarly to the 465/475 then the pre-amp only has a couple/few range settings. If one of the ranges is "de-tuned" then this would show up at all attenuator settings, no?
Dave
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On Tuesday, January 12, 2021, 08:50:25 AM PST, Jeff Dutky <jeff.dutky@...> wrote: I'm not sure if I'm just holding it wrong, or if there is something terribly wrong with my 2236, but I noticed that the 2 mV and 5 mV ranges on both channels read exactly the same. I first noticed it on channel #2 while calibrating my 475A. I would start the 2236 and the 475A on the same range, adjust the signal generator to give me a 4 division signal on the 2236, check and adjust the 475A based on that signal, then switch to the next range up on both scopes and repeat. I don't need the 2 mV range for the 475, whose lowest range is 5 mV, but I accidentally turned the knob the wrong way, and was surprised that the display didn't change. I have a picture of the scope taking the same signal on both channels, one set to 5 mV and the other set to 2 mV, showing that the two signals read as the same amplitude (and another picture showing the ranges reversed, so we can see that it's the same on both channels) /g/TekScopes/album?id=259300&p=Created,,,20,2,0,0 The only difference is that the 2 mV range shows slightly more noise on the signal than the 5 mV range, which is what you would expect from the higher sensitivity range. Maybe the scope is just poorly calibrated? (or, maybe "poorly" is the wrong word, maybe "intentionally miscalibrated so that both ranges read the same"? You'd really have to put some effort into making both ranges read the same during the calibration process to get this level of agreement) -- Jeff Dutky
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2mV and 5mV ranges read the same on 2236
I'm not sure if I'm just holding it wrong, or if there is something terribly wrong with my 2236, but I noticed that the 2 mV and 5 mV ranges on both channels read exactly the same. I first noticed it on channel #2 while calibrating my 475A. I would start the 2236 and the 475A on the same range, adjust the signal generator to give me a 4 division signal on the 2236, check and adjust the 475A based on that signal, then switch to the next range up on both scopes and repeat. I don't need the 2 mV range for the 475, whose lowest range is 5 mV, but I accidentally turned the knob the wrong way, and was surprised that the display didn't change. I have a picture of the scope taking the same signal on both channels, one set to 5 mV and the other set to 2 mV, showing that the two signals read as the same amplitude (and another picture showing the ranges reversed, so we can see that it's the same on both channels) /g/TekScopes/album?id=259300&p=Created,,,20,2,0,0 The only difference is that the 2 mV range shows slightly more noise on the signal than the 5 mV range, which is what you would expect from the higher sensitivity range. Maybe the scope is just poorly calibrated? (or, maybe "poorly" is the wrong word, maybe "intentionally miscalibrated so that both ranges read the same"? You'd really have to put some effort into making both ranges read the same during the calibration process to get this level of agreement) -- Jeff Dutky
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Re: I built a TM500 mainframe tester, and updated the design. Someone might find this useful?
Thanks, Oz.? I will hesitate no more.? I have used OSH Park before, and yes, the quality was very good.? ? JimSent from my Verizon, Samsung Galaxy smartphone
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-------- Original message --------From: Oz-in-DFW <lists@...> Date: 1/12/21 8:03 AM (GMT-08:00) To: [email protected] Subject: Re: [TekScopes] I built a TM500 mainframe tester, and updated the design. Someone might find this useful? On Thu, Dec 31, 2020 at 06:22 PM, Jim Ford wrote:>> Not sure where they are located, so I hesitated to mention them>They're in Portland. They are an aggregator that used US suppliers. They are far more expensive that Chinese suppliers, but usually superior quality.? Certainly more reliable quality. They are much more competitive for quantity orders. -- Oz (in DFW) N1OZ
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Re: I built a TM500 mainframe tester, and updated the design. Someone might find this useful?
On Thu, Dec 31, 2020 at 06:34 PM, Larry McDavid wrote:
Ok, I'll ask OSH Park for a quote and compare quotes.
No quote, they bill by board area. If you upload Gerbers they calculate the area and cost, so that's sort of a quote. -- Oz (in DFW) N1OZ
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Loop gain is sensitively dependent on the amplitude of the snapoff pulse and the cathode temp of the tube. My 1S1 is fitted with a heater regulator board that was not regulating due to a short; it is more stable now that I fixed it. I added my repair notes at . HTH, Dave Wise ________________________________ From: [email protected] < [email protected]> on behalf of Tim Phillips via groups.io <timexucl@...> Sent: Tuesday, January 12, 2021 1:15 AM To: [email protected]Subject: Re: [TekScopes] 1s1 on ebay from Tim P (UK) Yes, I expect the lucky owner may well be asking about the 1S1 and it's foibles ! I have four - one works, but needs the Loop Gain tweaking every time I use it, one triggers but won't sweep, (nothing at the Horiz Out jack), one free-runs but won't trigger, and one won't sample, although I see strobe pulses. The Diode Dance of Death ? Tim
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Re: I built a TM500 mainframe tester, and updated the design. Someone might find this useful?
On Thu, Dec 31, 2020 at 06:32 PM, Larry McDavid wrote:
Why would using Chinese made boards require a different physical design?
Design rules. Inexpensive Chinese suppliers (not all Chinese suppliers!) usually have coarser trace and space rules. May or may not be a factor. -- Oz (in DFW) N1OZ
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Re: I built a TM500 mainframe tester, and updated the design. Someone might find this useful?
On Thu, Dec 31, 2020 at 06:22 PM, Jim Ford wrote:
Not sure where they are located, so I hesitated to mention them
They're in Portland. They are an aggregator that used US suppliers. They are far more expensive that Chinese suppliers, but usually superior quality. Certainly more reliable quality. They are much more competitive for quantity orders. -- Oz (in DFW) N1OZ
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Re: 7633 no high voltage -1475V on test point
Fabio,
Check through the theory of operation in the manual. The high voltage is generated by the transformer T1199 driven by the power oscillator Q1195, the circuitry is protected by the fuse F814.
There are two common causes of failure, one is on the driver side, Q1195, Q1190 and C1198 / L1198. You will need to remove Q1195 which is on a sub-panel and heat sink in order to test it.
The other common failure is either the transformer T1199 itself or a failed capacitor or diode on the high voltage side of T1199. High voltage failures are more difficult to diagnose since leaky components often show as OK when tested with an ordinary DMM.
Regards,
Roger
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Re: 2445B delayed By sweep
Ondrej,
That sounds like perfectly normal behaviour. If you have a 100nsec display window for the B sweep and a 1kHz repetition rate then the beam is only turned on for 10^-8 sec every 10^-3 sec so one part in 10^5. You would see a similar intensity if you look at a 1kHz calibrator signal at 10nsec/div with just the A sweep but the 24x5 calibrators change their frequency with sweep speed.
Regards,
Roger
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I don't think eBay marks auctions as "sold" or "complete" until the item is paid for. Also, for non-BIN auctions, "ended" can mean the listing duration has expired without any bids (or bids meeting the reserve price).
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It must have been. The auction is now "ended" but not shown as sold.
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On Mon, Jan 11, 2021 at 7:00 PM John Williams <books4you4@...> wrote: This looks pretty good. I don¡¯t know anything about the seller though.
Almost too good to be true.
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Hi,
I'm wondering if what I'm seeing is normal or not. I had some narrow pulses wide apart to display, it was give or take 1kHz and spikes were some 20ns wide.
When I used the delayed B sweep I could only get rather faint B sweep intensity. When I turned the intensity readout and scale illumination low enough to be similar intensity to the B sweep the picture I obtained was quite good but it was in rather bright room with glares so it wasn't easy to read at all.
Is there some separate calibration setting which might have drifted or is it normal behaviour?
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Re: DSA602A parts available
Hi,
I could really use the power supply sections!
In the UK, but happy to pay shipping.
Steve
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On Sat, 9 Jan 2021 at 23:25, Ed (SCSKITS) <scskits@...> wrote: If anyone needs DSA602A boards or mechanical parts let me know.
Unit is disassembled but metal will be recycled and boards listed on EBAY
in the next few weeks.
ed
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Re: I built a TM500 mainframe tester, and updated the design. Someone might find this useful?
Is DP me? If so all is well...
Thanks
David
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-----Original Message----- From: [email protected] < [email protected]> On Behalf Of Larry McDavid Sent: 11 January 2021 22:51 To: [email protected]; Tek500 Mail List (New:Groups.io) < [email protected]> Subject: Re: [TekScopes] I built a TM500 mainframe tester, and updated the design. Someone might find this useful? Folks, I'm closing this group purchase at this time; no additional requests will be accepted. Please send me a private email with your postal mailing address; don't send this to the whole Group. If you live in the USA, include your full Zip+4 Zip code. If you don't know your full Zip code (why would you not?) you may find it here: You should find my private email address in the header of this Group email. If not, use lmcdavid at lmceng dot com. Those "l" characters are the letter, "L." Please check the list of initials shown below for your participation. I found some duplicate initials and have corrected that. ML ML ML PA SM DC HB GL MH JRe WR JT EW EW EW EW RD AW SG DS JF MU PE SN SC AAlt BHu EPa WS KT RDD PMu GM CC BHe BK LR MPe MPe MPe SA BG JK AAin PTC PD BO JG EP BL CT MD RLG CB CH DM AD JRa JRa CR PM SW JW DP DG HV BH EL TP TP LM Final pricing will follow. Larry McDavid On 12/31/2020 11:27 AM, Jared Cabot via groups.io wrote: Hi all,
I have been accumulating TM500 modules and mainframes for a little while, so I recently finished building an 067-1201-99 TM500 mainframe tester from the Tek construction notes floating around. -- Best wishes, Larry McDavid W6FUB Anaheim, California (SE of Los Angeles, near Disneyland)
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Re: PM - Address Re: [TekScopes] I built a TM500 mainframe tester, and updated the design. Someone might find this useful?
Hello Jeff,
I am most interested in one set in good state, with covers.
Please send photos.
Would require postage (flat pack) to AUSTRALIA.
Cheers,
Rick (RLG in Larry's list).
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On 12 Jan 2021, at 11:12, Jeff Kruth via groups.io <kmec@...> wrote:
Hi All! Just today I found 4 custom assemblies here, built in TM-500 frames. One is missing the covers. They have a front panel that may be adaptables for the project. I would like 15.00 each for the ones with covers and $10 for the one without (good top & bottom rails plus the front panel. All plus postage. I can knock these down and ship flat in a flat rate box. PM me if anyone wants one. I will try to send a pic later. Jeff Kruth
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1S2 plugin wanted in Europe
Tek fans,
I'm afraid I haven't been active on the list for a while because emails started bouncing for some reason and groups.io cut me off. I think I've fixed that now, though, so can join in again.
Like many people I've done a lot of working from home over the past few months, which has meant that my trusty 535A with its various plugins has been earning its living. I've enjoyed using it very much. I now have the feeling that my life would be a little more complete if I could find a 1S2 sampling/TDR plugin. It would genuinely be useful as well as technically and historically interesting.
I realise there aren't many of these around, though I note that one sold on eBay Germany just before Christmas. I'm happy to pay a sensible price for one, and I don't mind if it's not fully working. Repairs are all part of the fun.
I'm in Warsaw, Poland, if that makes any difference but am happy to arrange international shipping.
Chris
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from Tim P (UK) Yes, I expect the lucky owner may well be asking about the 1S1 and it's foibles ! I have four - one works, but needs the Loop Gain tweaking every time I use it, one triggers but won't sweep, (nothing at the Horiz Out jack), one free-runs but won't trigger, and one won't sample, although I see strobe pulses. The Diode Dance of Death ? Tim On Tue, 12 Jan 2021 at 04:47, snapdiode via groups.io <snapdiode= [email protected]> wrote: Wow, you don't see many 1S1s these days, and not at that price! At best
the unit still works, otherwise I predict in a few weeks we'll get a new
member with many questions about getting a 1S1 to work.
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Re: I built a TM500 mainframe tester, and updated the design. Someone might find this useful?
Address sent privately.
Thanks Larry for your great work.
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Hi Vince,
Some querying determined the Prologic had reverted to Controller mode while the 2713 was in Talk Only mode. With this corrected, a Plot button push on the 2713 once again sends the screen graticule and trace info via Prologix USB to PrintCapture, however: there is no readout data printed, just the trace and a virtual graticule. Querying the 2713 diagnostics shows GPIB test Failed. Interestingly enough, the real-time clock does not update when the 2713 is turned off, even though both backup batteries have been changed. Both of these failures appear to be located on the GPIB board...
I'll continue to try and find a common issue, but the offer to purchase a known good #671-1859-0 GPIB board stands!
Cheers!
Howie / WA4PSC
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Dave Peterson
David C. Partridge
momemeca