Good eye, Vince. Yes, it's 575, and is in the repair/restore queue.
Great
So that's 3 of these beats on TEA... you, me and Oculus.
Anybody else has one ? I wonder how many there are here...
I know for sure that the base step selector switch is mechanically stuck in the 'repetitive' position, and have not yet powered it up to learn what other evils may lurk therein.
Hmmm.... funny you mention that, because I think that very switch on my unit is kaput too ! Not in the same way as yours, but still.
Just read the user manual to make sure I understand how it's supposed to behave, mechanically. I understand the "Repetitive" and "OFF" positions, are stable positions, and the third position, " Single Family" is spring loaded / momentary.
"OFF" and " Single Family " behave properly, from a mechanical perspective. However when I flick the switch to the " Repetitive " position... it's just flapping in the breeze. It won't lock/click into place, and offers zero resistance. It just falls back to the OFF position like a rock, as soon as I remove my finger from it. Broken switch then...
However from an ELECTRICAL perspective, seems like it behaves like yours : in any 3 position, it will display curves constantly.
So maybe that particular switch is a weak point in the 575...
I just powered up the beast to make sure I was not dreaming, before I posted this. Nope, no mistake. Except it seems the poor 575 is now going downhill for some reason ! The " 120 / 240 / 120 " STEPS / SEC switch is acting up. I just can't get it to display curves reliably, it just does weird and wonderful things at semi random when I touche either of these two switches. Sometimes it even displays what looks like a really neat animated 3D rendering of some hollow shape... poor 575 is completely losing it now !
So, it "
might " HAS some electrical gremlins after all, it's not just a cosmetic restoration anymore !
Well it's more fun this way.
I looked at all the tubes glowing in the thing... noticed one of them that really looks like it's not lighting up at all, not even really faintly. V132 (an 6AL5).
Looked it up in the schematics.... oh surprise, it's part of the base step generator !
A dual rectifier, both plates connected together and going straight to... "surprise " again, the STEPS / SEC switch !
Just checked my spreadsheet listing all the tube models contained in my Tek scopes. The 6AL5 is not very common... I mean all bar one (Type 547) has this tube but one and only one. Still, I have some then, so could swap that tube to see if that improves thins... most likely will...