G05 Driving me CRAZY!

jetusenet

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Donor 4 years: 2011, 2013-2014, 2024
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Hi;
I rebuilt a beat Deflection PCB and a pretty good HV PCB, all caps and transistors, a couple of diodes and resistors as well - All fuses replaced and the bridge rect. too.

Anyway, I fired it up and I got a pic with retrace lines all over the place and once shut down, a small spot in the center that dashed across the screen before fading. Brightness and Contrast had no effect at all.

I pulled the HV and Def PCB for a going over and once reinstalled, no pic....
I had:
Def chatter
Neck glow
Fuses good
B+ 40v
91v
408v
and 408 on the focus
12Kv on the CRT

But no pic. I tried the brightness and contrast, no effect.

I pulled the Def again and went over the Z channel and check all the components in circuit - looks good. I put the board back into the Electrohome and back to all the retrace lines, contrast and brightness, no effect again......

I placed a known good def PCB in the monitor and all is well.....

Does ANYONE have ANY ideas of what could be causing this on again / off again situation with the def PCB??!?!?!?

Thanks in advance....

Jeff
 
CRAZY - CRAZY - CRAZY!

I guess that I am going to have to sound out all the traces next.....

UUG.
 
I had an issue like yours...rebuilt everything (new pots, caps reflow solder...). Turned it on and real bright with retrace lines and no change turning brightness or contrast. I ended up finding one of the solder pads on the brightness pot had lifted and was not making contact. Put in a jumper wire from that damaged leg to where the trace went and the problem was solved. Hopefully your problem will be that easy. Good luck!
 
Thanks for the tip, I checked the pots at the solder point but not any further than that.
Tonight I will be sounding out all Z traces and I will start with the brightness and contrast first.
Jeff
 
AWWWWWWRRRRRRRRIGHT!!!!!!!!

When I was testing the voltages, I was sticking the back of the Molex connectors so everything appeared to be fine...... well.....

Pin 1, which gets the 90v from the HVT kinda backed out of the deflection PCB Molex connector so even though it looked good on the foil side, as there was fresh solder there, there was a intermittant connection!

I desoldered all the Molex connections to the PCB, pressed the pins through real good and resoldered it all back together.

I got game!

Thanks again for all the suggestions.

Jeff
 
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