Flyback Failure

[nasadowsk]

Ahhh

I 'hotwired' the vert section. It boots weakly, but I didn't see anything that approached a keystone in the raster - it looked about as square as I'd expect.

I decided once again to measure the 340 supply (the main B+ for the sweeps) and found it...at 270. Hey, being 70 volts down could be a problem

I pulled the audio output and gained 5 volts. Joy. Looks like I've got to replace all the 'lytics too. The paper guys are comming this weekend, I'll get them then turn my attention to the electros. I've got a few temp ones I can jumper for now.

The flyback's ice cold. I'm guessing at this point I've just the classic bad caps issues here. I'll revisit the HV and all later on - the 130V supply for the RF/IF/Vid sections is a totally independant supply - I can pull the 5U4 to shut the big HV stuff off, and just get those guys up and running since they're likely gonna need help too.

I'm guessing, since I don't need the sweep stuff going when I check the set's alignment, that I can just pull the 5U4 to disable it all. Should be quieter and safer anyway.

BTW, the alignment proceedure on this set's a dream, just plug in a VTVM at one point, and apply signal at a few frequencies and peak/null a few coils, in order. They don't even really cover sweep alignment, just say to check for a waveform and touch up. I like this - I'm, not a huge fan of sweep alignment, even though it looks cool, I find they generally don't cover the interactions of the coils well, the desired curves are always tiny and not drawn to scale, and you need a ton of equipment to do it, unless someone makes a decent all in one alignment generator that's flexible enough to do old sets like this one....

Anyway, it looks like I gotta go through nd replace a bunch of caps and find out why I'm not getting 340, first. I thought I was, but I guess I misread the meter when I checked it the other day...

Well, looks like there's a light at the end of the tunnel - and heck, at 8-9kv, the CRT's not too dim, so maybe it's really good for a change. It's a Raytheon branded tube - nyone know how well they fair? Too bad it's not Sylvania - the two sets I've had with those were beyond good....