It pays to be methodical (though, in this case, the one getting payed appears to be Mouser): I went back and measured the voltages coming off the (unreg) power supply, and the +40 V rail is also very

Siggi wrote: I think that the per-color part of this is probably explained by the order of the color shutter actuation, but I can't quite make it make sense either. If we simply had something that was

#photo-notice

Okay, sorry I didn't read carefully enough. From the documents on TekWiki I'm betting that the color is produced by the "shutter" assembly in front of the CRT, and that the CRT is monochrome. That wou

#photo-notice

Do you have a VGA display that you can attach to the rear video output? Do the blue stripes appear on the external VGA display?

#photo-notice

Scott, these do exist, but they are exceedingly rare. I have been searching for one for the past few months, and have only seen them sold along with the scope, and then only a couple of times. I have

Could you upload pictures of the malfunction ("all lighting green") and the effect of BEAM FIND ("vertical or horizontal bar")?

Tom, Sealing wax, according to wikipedia, can contain beeswax. I'm a little surprised that candle wax would be used to try to hold a transformer together, my impression of it is that it is both brittl

Oddly, the wikipedia entry does not list any use for beeswax in electronics, either current or historical, similarly the electrical properties of beeswax are not discussed. I'm very curious how beeswa

Harvey, thanks for the explainer, between that and the Theory of Operation section I should be able to figure out what's going on in the -15 V regulator. I went back to the start, found an appropriate

Harvey, Thanks for that tip, that really helped me validate the connections to and from the power supply. Between the indicator triangles and my check-in photos I was able to verify that all the cable

A correction: where I wrote that the -15 V rail now measures as -21 V, I should have written that the -18 V rail now measures as -21 V. I appear to have mis-transcribed the spec value for that power r

I have added 19 photos to the "Sick 7623A" album showing the current symptoms and the "check-in" photos I took before doing any work on the instrument. https://groups.io/g/TekScopes/album?id=260677

Dennis Tillman wrote: I'm only guessing that it's silicone. I've not gotten a great look at it, actually. I thought, in the GRiD laptops, that it was a solid seal over the top of the socket, based on

Dennis Tillman wrote: I have seen something similar on GRiD laptops from the early to mid-80s, used for extra low-profile socket mountings on the CPU and FPU, for example. The original strips had a se

Jean-Paul, I will post photos shortly to the "Sick 2365A" album (https://groups.io/g/TekScopes/photos?p=created,,,20,2,20,0&jump=1) I have the service manuals from TekWiki, which purport to be from 19

Dennis, So it doesn't look like any of the available sockets (at Mouser, at least) have the silicone gaskets that the Tek sockets seem to have. Do you know if that was something Tek did themselves? --

The replacement parts finally arrived for my repairs to the 7623A. I replaced C811, and Q956 (which I think I killed by accident), and managed (I think) to reassemble everything (I will say that my re

Bert Haskins responded to: Okay, I'm not disagreeing with you (I'm kind of interested in a good X-Y mode too), but, for curve tracing, aren't there any good, modern, purely digital (as in all data col

Guessing, without the benefit of actual knowledge (other than what I've seen from tear-downs on YouTube) but modern DSOs, at least the lower end units, seem to be very mixed beasts for repairability:

(of course I meant to subtract reverse current from forward current)