Remove the bottom cover, there are relays accessible from there.

I'm repairing my newly acquired 576, it doesn't have any voltage on the collector supply whatever settings I use. I've checked and repaired the interlock switch on the safety box, but still no luck.

Well, someone was having a "Friday afternoon" time when all this was done, because my 475A manual (070-2162-00, Rev. D, Sept 1979, if any of that is significant) shows the tolerance of 290-0523-00 as

Bob, This is great.  Another project for me to build.  Michael Lynch 479-226-0126 Home Phone479-477-1115 Cell Phonemlynch001@...@gmail.commlynch003@...  

Bob,     This is great I cant wait for these to be available. Looking forward to this one. Eric

Curiosity got the best of me, so I went to the TEK Common Parts Manual for Capacitors and confirmed my statements above, Here is what TEK shows for the specifications of 290-0523-00: "ELECTROLYTIC,

I am working to finish the firmware and hope to have it out in a couple of weeks. The vintageTEK Museum will publish the circuit board layouts and schematics in KiCad and the firmware source code. We

All: I am betting that the 475 manual is in error stating that these are ceramic caps, I have 475 and 475A manuals open side by side. Both manuals show C1091 and C1093. Both manuals show the same

Bruce, don't be shy about replacing suspect components while you have access, think of it as insurance. As for lack of trace, I agree that there could easily be more faults yet to be found elsewhere

Dennis, I added a Tektronix 4041 photo album with photos of my 4041 running the System Verification tape. https://groups.io/g/TekScopes/photo/247590/5?p=Created,,,20,2,0,0 Monty

Hi Bruce, I was teasing you when I only gave the mathematical expression. You're right about the sine wave background but a calculus approach is more straightforward than a geometrical approach. It's

Hi Bruce, I don't have a 475, but I've looked at the service manual that is available on TekWiki. The service manual description of C1091 and C1093 is suspect, where they are listed as 350V ceramic

Hi Graham, Very encouraging! Thank you! I'll cross my fingers that your reasons 1, 2. and 3 hold true and I'll be finished when the caps go back in. Since I have not seen any trace on this scope, I

Bruce, good to hear of your fault-finding success so far. Extracting all the power supply capacitors out is a bit adventurous but you've done it successfully and it certainly allows you to test each

Hi Albert, Yup, 2.22 is ~ pi/√ 2! And I did not know that, but I thought the consistancy of the ratios between those measurements on each rail might indicate something to somebody, and you were

This message appeared a couple of days after I made an eBay purchase of 5 1 foot long cords for $9.99+tax. I was aiming for the lowest possible cost. I figured 1 foot was the right length for me since

Hi Wasteland Tek: Such a cool name! I'm envious. I must have missed the "unpleasantness in Portland?" No.. there's a story to this one; but, I don't want to trigger the TekScope vigilantes so it will

Hi Reed, Yes, and it turns out you were right about that. I didn't do it, for the reasons that I had already decided to pull out all the large caps and replace them, plus I didn't see your

Graham, I forgot to mention that I WILL be investing in a higher end DMM. While the GME-236, a recent acquisition, is quite handy for quick checks of ESR of in-circuit caps to find questionable or

Thank you, Graham! If you read the post I just made a few moments ago, you know you called the bad caps ahead of time! I just need to check the associated rectifiers. I don't think I should be