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Chuck, I had the same fault as in Joel his 515A in one of my 502As. It seems you checked filament voltages delivered by T601 and concluded that these were good. But the CRT winding fault is not a

Hi Chuck, I have seen the same failure in my 515A, and the cause was a failure of the EHT transformer resonating capacitor which became leaky after a few minutes. In the 503, this capacitor is C620

Aargh! Thank you, John. -- Cheers and more aargh Tom -- Prof. Thomas H. Lee Allen Ctr., Rm. 205 420 Via Palou Mall Stanford University Stanford, CA 94305-4070 http://www-smirc.stanford.edu

ChuckA: OK, I believe you are correct in determining that T601 is likely not the problem.? I did not pay as much attention as I should have to your original email where you already mentioned that

I've pretty much verified that the LV supply (T601) is good. When the T602 voltages drop the +500V output from T601 doubler stays constant, as do the filament voltages. ChuckA

If you post the Spanish text I can translate it, I'm a native Spanish speaker. Ignacio -- Este correo electrónico ha sido analizado en busca de virus por el software antivirus de

The data sheets are right.? There was an alternate reversal of in and out on some gates.? IIRC, the 7401 and 7402 have that reversal.? I've avoided the heck out of using those parts. The 7400,

Better check the data sheet. On the 74S00 NAND, pins 1 & 2 are input, pin 3 output, on the 74S02 NOR, pins 2 & 3 are input, pin 1

The voltage breakdown of the CRT heater winding, which can indeed be resolved by installation of a new 6.3 VAC filament transformer, is a not uncommon failure mode for many 500-series scopes.? But it

The LV transformer is good, the filaments are sourced from that transformer except for the 8393 Nuvister vert input amps. The HV transformer supplies the +250V, +85V, +100V, +12.6V, -100V & -3000V.?

My memory isn’t good on this, but 30 years ago I had to wire in a separate filament transformer for the CRT. I don’t recall the symptoms that led me to this fix. I used a junk box filament

I picked up a Tek 503 scope recently and decided to get it running. Found only one bad filter cap. But it appears the HV transformer T620 (pn# 120-199) is bad, all the voltages out of it gradually

Perhaps this may help someone in the future. I was contacted by a woman in Delaware whose father was a collector. I was given a lot of 8 scopes. Nothing incredible, mostly 4xx series. There was a 485

This showed up on my Pinterest feed and is from an NY Times Article: https://pin.it/1ovGjfD The system the woman is using is a LINC-8. The original Laboratory Instrument Computer (LINC) was

I'd cut and paste the Spanish text into an online Spanish-to-English translator, or, if the text is on a website, as you indicate, use Google translator on that page. DaveD KC0WJN

I see what you mean. In that case, I won't cloud the issue with any more suppositions. I'd be interested in seeing if you find any clarification on it. Thanks, Barry - N4BUQ

I added more photos. All the other positions match except ch1

I have a 495 spec analyzer with a phase lock failure. Theres a post on this cite in spanish that was a fix. Is there a translator on this cite? I havent explored other apps yet.

If that's the case, then it appears that agrees with CH1. The contacts are listed in 4123 order in the manual so it appears that is the position for CH1. Barry - N4BUQ

The one in the manual has 4 switch contacts because the first one is the power contact that is omitted in the mode select section. The first contact appears in the powersupply section. Ignore the 1st