I *THINK* that you can safely power the scope without the digital boards installed. but I never tried that. Does anyone know if it's OK to do that? I can't think of any potential nasties except possib

Yes, but that was a very high leakage failure (almost a short) on a 7K series logic board. I've known them to crack and fail open as well. Anyone have some other cases to add? David

OK here's some thoughts: 1) The -5V supply measured at [2] at the input to L68 should have about 100mV peak to peak saw-tooth ripple at about 50kHz which is before the output filtering network (see th

The ripple on the -5V looked really quite high ...

Personally I'd use neutral cure silicone. Hot glue gun glue is a pain to remove when you need to.

The +12V and +5V values you report below seem pretty OK to me. You didn't say anything about the -5V line ...

Maybe he's of the KISS lobby :)

The digital board supply is only accessible if you remove all the logic boards - it hides away at the front of the 'scope to the left (as viewed from the front) of the logic boards. You can't get at t

Be aware that there is a secondary power supply for the digital stuff which lurks at the front of the scope. It's quite likely if there is a PSU problem that this is the one that is the culprit given

Most humans are a lot more random than a PRNG! :) David

Looks like groups.io gave an incorrect link for the file location: https://groups.io/g/TekScopes/files/THS720%20Battery%20Rebuild%20Process/tek-ths720-battery-replacement.pdf David Sent: 29 August 202

#file-notice

Please post their email here. David

You need to get the service manual - it tells you how to remove the CRT. The problem is likely the silicone sealant where the EHT is connected has failed. You'll need to clean off the old and re-seal.

Typically you need a faster repetition rate on your test signal for it to be bright at 500pS/div. I'm guessing that you were using a fast rise pulse from a CG551AP or CG5001 or PG506 for calibration.

They are miniserts see: < https://groups.io/g/TekScopes/files/Minisert.pdf>

https://www.ebay.co.uk/itm/254685390375 Is this produced by one our members? David

Courier new is good for ascii artwork as it's mono-pitch. D.

The max output of a pg506 in fast rise mode (which is what you want) is between 100mV and a bit over 1V peak to peak. David

It was an admin error, they will post them David.

I didn't raise the point at the time, and 'm really not trying to tell you "how to suck eggs": Did you check with the person involved? It is possible that his email had been hi-jacked, and that he was