Tempest plays blind

chips4sle

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hey
just curious if you could lend a had fixing this tempest pcb. got a tempest pcb that was supposed to be working and its not.so im trying to get it working .

the pcb plays blind
monitor is rebuilt
checked pcb in another tempest and have confirmed that its the pcb

checked the cable and the header pins
resoldered the header pins
i get a light on the pcb and on the monitor

put in new big bluw and fuse holder

what to try next?
 
Check to see if you get readings at the +15 and -15 lugs. This is DC voltage. I had a Tempest once that didn't output to the screen with one of those missing...
 
You're meter may not be fast enough to notice the swing. Have you confirmed that the monitor works with another board?

Do you have an Oscope that you can hook up to the board?
 
hi
im positive that its not the monitor
ive tried the boardset in 2 other machines

also if i turn the brightness up all the way i get a faint pic on the right side of the monitor
the whole picture is very small, maybe the size of an index card
 
hi
im positive that its not the monitor
ive tried the boardset in 2 other machines

also if i turn the brightness up all the way i get a faint pic on the right side of the monitor
the whole picture is very small, maybe the size of an index card

Is the picture that you are seeing a Tempest screen or random garbage? If you turn the brightness all the way up you should have very bright lines running thru the monitor screen. Did you rebuild the monitor?

If you have a very small Tempest picture, you need to adjust the image size using the pots at the ned of the PCB marked X size and Y size. Make small adjustments.
 
hi
the pic only shows up when i turn the brightness all the way up. also the pic looks to be a partially tempest screen all the way over to the right

monitor has been rebuilt and works
 
it sounds like your game is running and putting out a picture- maybe there is just something zapped in the final output section of the game board.

I don't think anything is socketed there though, so you'll have to unsolder chips and test replacing them.

Check those little potentiometers too. They have fragile legs that often break from repeated flexing.
 
Yep, you can check them with an Oscope, but I would check the pots first. If you loose a leg on one of those things it will cause issues like that. Normally if you loose on of the op amps, or mc1495s you will loose picture all together, as you will loose x or y and the spot killer kicks in.
 
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