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Re: OT: Seeking help reviving a Stanford Research Systems SR760 Spectrum analyzer
Ask Stanford directly - AFAIK they have always provided Service Manuals with schematics and still do. Dave
By David C. Partridge · #150145 ·
Re: 495P A54 Memory Board Troubleshooting: continued
Please don't continually re-edit your post - those of us who receive posts by email (most of us) set the same post over and over with minor edits. Thanks Dave
By David C. Partridge · #150144 ·
Re: 7704A Z-Axis Problem
Hi Tomas, The HV transformer works at the SMPS frequency. Hence in theory you cannot distinguish yet whether the intensity ripple originates from the HV or from LV ripple entering the Z-axis
By Albert Otten · #150143 ·
Re: 7L13, more exact frequency readout
If your 7L13 is anything like my 7L12, it should have a 'phase lock' switch which locks the 1st LO to a multiple of some frequency (about 700kHz, I think) for spans of less than 200kHz/div. This works
By cmjones01 · #150142 ·
Re: 7704A Z-Axis Problem
A high voltage probe could show you 25 KHZ ripple on the HV lines. That, or some bypass capacitors failing would be a start. You could take a probe, place it near the HVPSU to get a signal, then tri
By Harvey White · #150141 ·
Re: 495P A54 Memory Board Troubleshooting: continued
DSO works. Since the chip is one way only, you look at the schematic and see where the offending pin is supposed to be output to the bus. Let's assume it's D0, then on the input, you have a steady
By Harvey White · #150140 ·
Slightly OT - Bourns trimmer pot failure
I finally succeeded in breathing life back into my Tek 634 display today but, as it turned out, only briefly. Thanks to google, an expired ebay link and a really helpful chap in the US of A I got my
By Adrian Nicol · #150139 ·
Re: 7704A Z-Axis Problem
I just checked and sadly it does not. The pattern stays exactly the same!
By Tomas Alori · #150138 ·
Re: Replacing Electrolytics in a 465/465B
Hi Barry, Deal done ! I will sent you right now an e-mail off the group for personal information. Please let me know if you do not receive it. Thank you Victor
By Victor · #150137 ·
Re: 7704A Z-Axis Problem
Does the pattern disappear if you turn the read out intensity to zero? Roger
By Roger Evans · #150136 ·
7704A Z-Axis Problem
Ever since I got my 7704A I could always see a running dot-pattern on the trace that would go to the right or left, depending on my horizontal speed setting. I'ts most visible in the 100uS/div and
By Tomas Alori · #150135 ·
Re: 495P A54 Memory Board Troubleshooting: continued
Harvey, Thanks for your suggestions. I have a DSO (but none of the other gear you mention) which may be helpful, but perhaps easier just to change the IC. RB
By Rick Boswell, K8EZB · #150134 ·
Re: Desoldering Iron vacuum
How about a condensate drain valve? Do you have that to let water out the bottom of the compressor shell/tank? A small refrigeration compressor from a water cooler might be a good size for venturi
By John Griessen <john@...> · #150133 ·
Re: Replacing Electrolytics in a 465/465B
Hi Victor, Shipping will be $14 and $15 for the three boards so $29 total. Let me know if you're still interested. You can reply off group if you'd like. Thanks, Barry - N4BUQ
By n4buq · #150132 ·
Re: 2215A LVPS repair
Ringing test To check transformers. The transformer must be removed first. To do this you apply a small!!! pulse across one winding and observe the amount of ringing. This will show a lot of ringing
By Bert Haskins · #150131 ·
Re: 2215A LVPS repair
Hi Leo, I think Bert is talking about the little transformer use din the pre-regulator circuit, rather than the big primary transformer. Indeed the pre-regulator transformer is a common weak point. I
By Vince · #150130 ·
OT: Seeking help reviving a Stanford Research Systems SR760 Spectrum analyzer
The other day, I was given an SR760, presumably with a faulty CRT. I don't know where else to go for help, so I'm turning to you guys and girls. If someone can recommend a place to seek help, please
By Raymond Domp Frank · #150129 ·
Re: Replacing Electrolytics in a 465/465B
A possibly clean one-shot solution for replacing these pesky filter caps is on my mind. I was given a non operational Tek 465 just before i retired. The +55VDC rail is sitting at 41.6VDC, it is the
By james morton · #150128 ·
Re: Desoldering Iron, was Re: [TekScopes] 466-464 stray wire
FWIW I have also built a "silent" compressor. Well, I had to, after switching that monster from the DIY store on the first time I knew I wouldn't put up with that racket. I took a refrigeration
By stefan_trethan <stefan_trethan@...> · #150127 ·
Re: 495P A54 Memory Board Troubleshooting: continued
On Sat, 28 Jul 2018 08:26:52 -0700, you wrote: If you have a dual channel scope, preferably one that does storage, or a digital scope, or a logic analyzer, then you're looking for a coincidence of the
By Harvey White · #150126 ·