Punch Out colors off missing green

dethfactor

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So I finally got my punch out together this evening and the monitors I bought are being silly. The adjustments on the bottom (bias/color) are cranked pretty high and the monitor is dim but blown out. To my knowledge both of then were recapped before I bought them but I want a second opinion. On the top monitor green is completely missing. I swapped the inputs just to make sure the wiring is completely off and the issue remains for both monitors.

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Thanks for the 411 but I don't think my issue is with the PROMs. I tested the board in a friends cab and the colors were fine. I think there's an issue with the Green circuit on the monitor as I had no green on the top regardless that I flipped the inputs.

I stupidly neglected to read the Sanyo EZ troubleshooting guide sticky before I posted and I downloaded Ken Laytons manuals. I'm going to pull the board and re-cap them and test the appropriate parts for the green circuit and see if that rectifies it.

Will post more when I complete my task tomorrow night.
 

Ok. So I may have jumped the gun with ruling out the proms. I went ahead and capped the top monitor and it still has no green. But I think I may have diagnosed that I have two issues with the top monitor. By process of elemination I noticed that when both the top and bottom signals are correct, the bottom monitor is perfect and the top is missing both the blue and green but when I swap the top and bottom signals I notice the blue is missing on the bottom monitor (top signal) and the top monitor (bottom signal) is missing the green.

So my blue prom for the top monitor is bad and there's a problem with the green circuit somewhere with the top monitor. What a pain.

monitors straight
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monitors swapped
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reflow the color drive transistors on the neckboards of BOTH monitors before you go pinning the cause on something. especially if you've recapped them. I had this same problem on my dual PC-10 after capping the monitors. cold solder is very much prevalent on these old monitors and the new caps amplifies it.

I tried swapping input harnesses on my PC-10 monitors and it did all kinds of bizarre shit that didn't really lead anywhere in the way of solving my problem until I pulled both monitors out and went over the entire neckboards. then all was swell.

additionally, you could try beating the shit out of the side of the cabinet... if your primary colors go in and out, definitely cold solder.
 
reflow the color drive transistors on the neckboards of BOTH monitors before you go pinning the cause on something. especially if you've recapped them. I had this same problem on my dual PC-10 after capping the monitors. cold solder is very much prevalent on these old monitors and the new caps amplifies it.

I tried swapping input harnesses on my PC-10 monitors and it did all kinds of bizarre shit that didn't really lead anywhere in the way of solving my problem until I pulled both monitors out and went over the entire neckboards. then all was swell.

additionally, you could try beating the shit out of the side of the cabinet... if your primary colors go in and out, definitely cold solder.

I appreciate the hands on approach of "beating the shit out of the side of the cabinet"

I know the bottom works because I adjusted it crystal clear and got all 3 colors. I also went ahead and swapped all the driver transistors on the top and still no green. The guy I bought it from said it worked great before they were shipped but who knows what happened during shipping. I'll reflow the bottom ones tomorrow and if nothing start tracing the green circuit parts and replacing them as noted on Ken Laytons trouble shooting guide. If that fails I might just keep beating the shit out of it for the hell of it.

Is there a proper way to test those driver transistors? I used the diode tester setting on my meter and didn't get continuity on any of the damn leads any way around the damn thing. Is there something special about them?
 
Ok so I went ahead and swapped the both chassis and the green was missing still. I also reflowed the transistors on both monitors and also swapped them between the guns and green is still missing.

Going to recap the other monitor, replace the pots on both and replace the problem components pointed out in Ken Laytons trouble shooting guide. Ordered another blue prom from Bob Roberts. All praise his mighty name.

Post more as I get more repaired. Any other clues as to the green issue, I'm all ears.
 
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