Tempest power brick voltage - am I reading this right?

When you say you rebuilt the brick and AR, what did you replace? Are you measuring the same brick voltages as before?


Regarding the board not running consistently, get a can of DeOxit and a fiberglass scratch brush (both on ebay), and remove all socketed chips, clean the legs with the brush, treat the chip legs and sockets with DeOxit, and reseat the chips a few times, to break up any corrosion on the legs and sockets.

It sounds like you have an intermittent connection, and the most common place for that to happen is with bad or dirty sockets, which a majority of boards have (and which is why I always replace them all, on the boards I overhaul). You don't want to start chasing other possibilities until you rule out the sockets.

You can also use a Dremel with a wire wheel on the legs, which is much faster, if you have one. That's how I do them now, but I used to use the scratch brush.

For the DeOxit, I spray a little into a bottle cap, then apply it in the sockets and to the legs with a small artist's paintbrush, to prevent making a mess, as the can sprays it too strongly.
 
When you say you rebuilt the brick and AR, what did you replace? Are you measuring the same brick voltages as before?


Regarding the board not running consistently, get a can of DeOxit and a fiberglass scratch brush (both on ebay), and remove all socketed chips, clean the legs with the brush, treat the chip legs and sockets with DeOxit, and reseat the chips a few times, to break up any corrosion on the legs and sockets.

It sounds like you have an intermittent connection, and the most common place for that to happen is with bad or dirty sockets, which a majority of boards have (and which is why I always replace them all, on the boards I overhaul). You don't want to start chasing other possibilities until you rule out the sockets.

You can also use a Dremel with a wire wheel on the legs, which is much faster, if you have one. That's how I do them now, but I used to use the scratch brush.

For the DeOxit, I spray a little into a bottle cap, then apply it in the sockets and to the legs with a small artist's paintbrush, to prevent making a mess, as the can sprays it too strongly.

I had bad off the shelf parts. The transistor in the center of the heat sink on the AR II was still bad after I replaced it. It came from a Bob Roberts kit that I have had for about a year and it wasn't the red Toshiba one. So, it took me a while to figure that out.

I also had two DMMs of the same brand that had gone bad.
I didn't figure that out until someone suggested I check the voltage coming straight out of my wall. When I tired that and got a reading of 175vAC things started clicking into place. The combo of the bad meters and bad off the shelf parts was making it fairly impossible to figure out.

My new meter is reading 5.0 volts at the +5 test point on the game board and if I watch it for a while in test mode I see voltage drops when the screen changes. It goes right back to 5v but drops as low as 3v while the screen is changing.
 
My new meter is reading 5.0 volts at the +5 test point on the game board and if I watch it for a while in test mode I see voltage drops when the screen changes. It goes right back to 5v but drops as low as 3v while the screen is changing.



That shouldn't be happening. You really shouldn't see it vary at all. Though I can't say I've watched it in test mode, but I wouldn't think that should make a difference. Are you watching it while manually cycling through the screens with the slam switch?

Is the voltage varying while in attract mode?

You should check the quality of your edge connector, to make sure it's not dropping voltage (i.e., is the voltage on the AR dropping the same way as it is on the game PCB? Measure both.)

If the AR isn't holding steady, you may still have an issue with it. Possibly the regulator.
 
That shouldn't be happening. You really shouldn't see it vary at all. Though I can't say I've watched it in test mode, but I wouldn't think that should make a difference. Are you watching it while manually cycling through the screens with the slam switch?

Is the voltage varying while in attract mode?

You should check the quality of your edge connector, to make sure it's not dropping voltage (i.e., is the voltage on the AR dropping the same way as it is on the game PCB? Measure both.)

If the AR isn't holding steady, you may still have an issue with it. Possibly the regulator.

It was in attract mode where I was seeing the voltage drops.

I will go back and check on the AR II vs the game board.

I was speaking to someone else about this and they called out the same thing about the edge connector so I believe that is my next target. I have the split pins though which seem to be a bit of an issue to find for repinning it.
 
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