WG 19v1002 Vertical Collapse?

ZmanZoo

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Greetings All,

I Just found these forums and have been having a blast reading up on Vertical Collapse issues, I believe this is my problem with my Space Invaders Deluxe Midway Cocktail.

after a quick search online, I ordered and installed a capkit from Bob Roberts, after reading some of the posts here I guess that wouldn't help but it's done now. :) reflowed/resoldered quite a few of joints on the monitors board, and still getting the same result.

So now I'm wondering if i'm diagnosing my issue correctly.

this is what it's looks like after about sitting 7 years in my garage (it worked fine last time i turned it on) I know shame on me for leaving it out in the cold.

can anyone help me bring my long lost back to life? let me now if the picture doesn't help.

Oh and I checked the +5 -5 +12.

Thanks for your time.
 

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Well I've looked over the board and resoldered more joints, every solder joint is starting to blur and look the same heh, I checked the 4 voltages on pins 2, 3, 7, 28 just for kicks and those all look good.

So I'm still wondering if i'm on the right track. I suppose Ill check some transistors but im getting the feeling im not looking in the right areas.

Any suggestions appreciated.

Thanks
 
Just so happens that my space invaders monitor looked very similar after a cap job and lots of looking over and testing.

I want to say that the culprit was Q217 P.U.T. but it was a long time ago. Kinda sticks out in my memory since it took forever to find and I was happy when I actually fixed the damn thing. (this was on a WG V1001)

 
I know this is old, but I'm researching.

My WG19V1001 kind of gave up the ghost on the vertical defl.

I get kind of what's pictured above. Slight deflection to the left, but none to the right.
I don't get the same waveforms as in the manual- my vertical drive has the peaks, but not the trailing off piece back to zero.

The Question is-
for the PUT MPU131 replacement, does the 2N6027 sound like a suitable replacement?
It's got the same basic parameters. power dissipation, forward voltage, max offset voltage..

I'll let you know how it goes.
 
Well, they both cross to the same NTE 6402, so they'd probably work as a swap for each other...
 
Well, swapped in the 2N6207 replacement and now I have NO vertical deflection.

That sucks.

One thing that was funny- the original MPU131 was mounted backwards compared to the silkscreen on the board.

The datasheet for the 2N6207 shows (w flat facing, legs down, left-to-right) anode, gate, cathode.

The ink on the board A, G, K corresponds to the schematic, and the transistor outline matches the 2N6207, but the MPU131 was mounted opposite the silkscreen.

I don't have a layout for the MPU131, but this monitor was working like that originally.
I mounted the new one in accordance with the schematic and the neighboring components.

I guess it's right. I should be looking at something else now. Maybe that Q210?
Didn't have time last night to pull out the oscilloscope. Kind of hard to see what I'm doing anyway inside of the cabinet.

K
 
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