Scope clock

Desmogod, Wed Jun 28 2006, 03:01AM

I have very little (i.e. no) experience with vacuum tubes at all, but I do have a 5UP1 RCA CRT that is sitting around doing nothing.
Has anyone else built a tube clock here? I can find info on a few other tube clocks, but none using this specific tube.
Is there anything to lok out for?
Re: Scope clock
Philcogrump, Fri Jun 30 2006, 04:20AM

What do you mean by "tube" clock? I've built a scope clock using OZ2CPU's plans available online: Link2 Also Link2 used to sell scope clock kits, but I think now he only offers the schematics for his.

The 5UP1 requires more higher voltages and is much larger, which is probably why no one (so far) built one using that CRT. Tube scopes using that CRT has a negative high voltage supply of about 1.5kV, and the postive supply is about 300V.

You might want to do a search online for Heathkit oscilloscope schematics from the 50s-60s, I think the model OM-3 or similar used a 5UP1. If you can build a whole scope from scratch using these schematics and the X, Y amplifiers are good enough, the PIC scope clock by OZ2CPU could work nicely. You won't need to use the Z axis because the dot moves so quickly in the "blank" areas that it appears blank without controlling the intensity.
Re: Scope clock
Wolfram, Fri Jun 30 2006, 02:35PM

I have made some scope clocks, but then never got beyond being just that, scope clocks. I never came as far as to make a PSU/deflection amplifier for the CRT so that it could display the time on the CRT instead of the oscilloscope. The OZ2CPU design works fine. A nice DAC to use is the 7528, as it is easy to get, TI (TLC7528), Maxim (MAX7528) and a few others make it. This is a current output DAC, to make it voltage output the output pins of it have to be connected to + and the output voltage is found on the reference input pins. This may sound a bit confusing, but it's explained much better in the datasheet. An other interesting scope clock design can be found at Link2 .