Rebuilt 6100 issues

Phetishboy

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I had the 6100 rebuilt in my Tempest machine about 4 months ago, caps, low voltage kit and it has a fan on it now. It has a great picture, great colors, etc. Now I was playing it on Friday night, and everything was fine. Fired it up Saturday night and let my daughter play it for an hour. She quit and then I left it on in attract mode for another hour and when I walked up to play it, I noticed the x-axis had grown immensely. The mazes and some of the text were being cut off at both sides of the bezel. I shut it off and turned it on today to find the same thing. I turned the x size pot on the board and it really didn't change much. I have it cranked to the smallest it will go, and it's still way too wide for the screen. Of course I messed with all the other pots to see if that would help and I just skewed the picture diagonally and then screwed up the kerning and text tracking. I have got it nearly back to how it was before I started messing with it, but the picture is still way too wide. WTF happened, and what do I need to do to fix it?
 
Well, I would guess that there could be one of three problems:

1) The X-Size pot on the Tempest PCB is failing. Sometimes the glue they put over them at the factory gets in there and screws it up, changing the range it can work in. You can test this by swapping the X-Size pot with the Y-Size pot (assuming your Y-Size is okay) as the pots are the same value. If your problem changes to the Y-Axis, then replace the pot.

2) When the chassis was rebuilt, were the frame-mounted transistors replaced? These are 2N3716's and 2N3792's. If one is starting to fail, it could affect just the X-Axis.

3) You have some type of blooming issue with the X-Axis. Pull your HV cage and inspect it for burnt resistors, etc. You might also want to measure the B+ at the spot where the orange wire from the HV cage connector goes to the neckboard. It should be about 180vdc. If it's way off, that could be an indication of a monitor issue in the HV section. You might try replacing ZD902 (not to be confused with D902).
 
Well, I would guess that there could be one of three problems:

1) The X-Size pot on the Tempest PCB is failing. Sometimes the glue they put over them at the factory gets in there and screws it up, changing the range it can work in. You can test this by swapping the X-Size pot with the Y-Size pot (assuming your Y-Size is okay) as the pots are the same value. If your problem changes to the Y-Axis, then replace the pot.

2) When the chassis was rebuilt, were the frame-mounted transistors replaced? These are 2N3716's and 2N3792's. If one is starting to fail, it could affect just the X-Axis.

3) You have some type of blooming issue with the X-Axis. Pull your HV cage and inspect it for burnt resistors, etc. You might also want to measure the B+ at the spot where the orange wire from the HV cage connector goes to the neckboard. It should be about 180vdc. If it's way off, that could be an indication of a monitor issue in the HV section. You might try replacing ZD902 (not to be confused with D902).

1) I'll try that

2) no

3) Time for the meter
 
Turned it on tonight, now all I have is a vertical line down the center. You can see the brightness/colors flickering and changing, as if attract mode is still happening, it's just happening in a 1/8" wide vertical line. This is great.
 
Replace the 6 frame transistors, and check to make sure none of the wires broke off of the sockets...
 
Check the output for your x and y axis on the pcb with your voltmeter set to dc (one lead connected to the x or y test point and one lead connected to the GND lug). both should be swinging between +5v and -5v dc not staying constant when turned on. If it is constant you probable lost one of the MC1495 next to your pots on the pcb. They can be piggy backed to identify a bad one. You will need a loose MC1495 chip. Line up the notch oriented the same way & snug up the pins so they will make contact with the mounted chip and slide it over the mounted chip. Turn the game on and see if there is a change. If your deflection is back and you can now see your game you have found the problem, Good luck!
 
Update. Pulled the monitor, replaced all frame mount output transistors. Used new heatsink compound, reused all gaskets. Found one wire broken, resoldered it on to its transistor leg. Plugged it all back in and now the spot killer comes on and the plyr 1 & 2 BUTTONS ARE LIT SOLID. DOES NOT PLAY BLIND, WILL NOT COIN UP, NO PICTURE. Every LED on the machine is lit up redder than Fritz's ass after riding side saddle during a rowsing game of wowboys and skindians. What should I start checking next?
 
BTW. unplug the connectors from the deflection PCB and do a continuity check between each transistor casing and the frame. You shouldn't have any continuity. Sometimes when replacing these, they'll get angled a little wrong and you'll get a short to the frame. If you find one, you probably need to replace that transistor again, and you may have a blown fuse on the deflection board...
 
BTW. unplug the connectors from the deflection PCB and do a continuity check between each transistor casing and the frame. You shouldn't have any continuity. Sometimes when replacing these, they'll get angled a little wrong and you'll get a short to the frame. If you find one, you probably need to replace that transistor again, and you may have a blown fuse on the deflection board...

Well that makes sense. God dammit I hate when this shit happens.
 
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