Re: Tek 7623A - Inverted and compressed Horizontal only from TB (SOLVED)

Fabio Trevisan

Thanks Jeff,
thanks for the heads up...
Well. I concur with you in that a problem which got solved by itself is a
problem ready to happen again and, moreover, while I exhausted all possible
explanations and having find none, I`m forced to let it be and, if the
problem ever recurs, I`ll have a chance to investigate more carefully (not
touching anything and just probing around) and eventually find the real
I have been working on other details of the scope the whole weekend, and
not a single time this problem happened again, between many, many power
cycles and removal and insertion of plug-ins...
It remains a mystery.
Good look with the 561... Tube stuff is completely out of my comfort zone.

2018-03-09 13:58 GMT-03:00 Jeff Urban <@JURB>:

Actually I don't like it when it happens. It could recur at any time.

if it does I would look to the mode selection, which is what switches the
IC's gain and who knows what else for the on screen display. While it
doesn't seem logical the sweep would be compressed if it was stuck in that
mode, the input could have been out of range.

I could be off base here, this is my first post and I have to admit to not
reading the whole thread.

But I got my feet wet. Soon I will be ready to start a thread maybe the
old timers might like - a 561. Has troubles in the vertical section after
an arcing transformer threw the DC from the negative bias into the
vertical. I have much information to put together so it probably won't be
today. Honestly, some of it will come from my posts on Usenet.

Be well all. See ya.

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