Re: G08 focus going in and out

Thanks for the 'focus' recommendations guys... unfortunately, my G08
story took a tragic turn today.

I took my HV probe and read the anode voltage. Looked good and steady
at 25Kv. Then I turned the game off and moved the rubber boot from the
focus control output (to get the probe lead in) and turned the game back
on. Interestingly, the focus fluctuations sped up more and more until
the picture started to stabilize... into nice sharp lines. Beautiful
picture. Alright! I tried to measure the voltage at the focus control
with the HV probe, but it was pretty low on the scale - about 5kv - and
not really wavering noticeably at this point.

This is the part where things started to go downhill... when I went
around the front side of the monitor I discovered, unfortunately, I'd
now lost horizontal deflection. Rats. So I took the deflection
transistor assembly out and replaced all the transistors with the ones
that came with my cap kit (2N3716's unfortunately). I utilized the
method of inverting the transistors for increased airflow through the
assembly.

Reassembled it and turned the game back on... still no horizontal.
Damn. Then instead of going and getting the scope out and checking the
board outputs like I should have, I reseated all the molexes from the
boardset, then turned the game back on and listened for deflection
chatter. I didn't hear any... but smelled smoke. Oh no!!! As I
watched, resistor 628 burst into flame, along with the one on the bottom
of the deflection transistor, and another one on the bottom of the
board. Damn damn damn damn damn!!! Turned the game off as fast as
possible.

Good thing the vertical channel is still good... it'll give me something
to look off of while repairing the horizontal.

Can anybody recommend a fuse rating for the deflection channels that
would actually save the components BEFORE they burst into flame?

Has anybody rebuilt one of these after a 'flameout'? (This isn't my
first vector rebuilt BTW; I've done three 6100's and two Cinematronics
monitors before and a couple of those were really messed up before I
got to them.)

                                                        -Lewis

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Received on Mon Aug 4 19:20:37 2008