Yet another Predicta Holiday restoration

[bandersen]

I finished with replacing the paper caps and resistors under the chassis. All the electrolytics too, but some are temporarily tacked in. I'll do a more permanent job once the set is working.



I'll be powering it up without the CRT using a power resistor in place of the filament.

Hmm, only 75 volts at the output of the filter choke. Should be around 300.


Eventually, I traced the problem down to the voltage doubler diodes. My DMM's diode check function showed them as good, but a 0.1 volt forward drop didn't seem right.

Sure enough, when I tacked in a couple temporary 1N4007, B+ came right up to where it should be, I got sound out of the and hear a high pitch from the horizontal circuit.


Finally, I popped the CRT off a restored Holiday set and got a raster


Even better, I can tune in a station although the vertical is messed up.


After adjust the vertical linearity and maxing out the height, I'm almost able to fill the screen. Also the vertical hold is very touchy.