WTB: Tempest Auxiliary board (working)

rhistr

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My aux board is messing up...anyone got one working they're willing to part with?
 
Definitely not against that! I'm horrible with soldering but getting better...I think.

Test mode shows EQPM error. I recently had the board serviced, and it worked fine for a while. The fellow who serviced it said it's unlikely all the components needed for those errors became faulty at the same time (given how it was functional a day before), so it could be whatever chip communicates between the two boards may be faulty. But that's the extent of my knowledge and understanding of what the problem could be.
 
Test mode shows EQPM error. I recently had the board serviced, and it worked fine for a while. The fellow who serviced it said it's unlikely all the components needed for those errors became faulty at the same time (given how it was functional a day before), so it could be whatever chip communicates between the two boards may be faulty. But that's the extent of my knowledge and understanding of what the problem could be.

That is true. However, also make sure the aux board is getting power.

Measure the 5V on both the main and aux boards. (There are 5V test points on each board.) Post both values here.
 
Eprom, both POKEY and the Mathbox all have an error. Not likely as noted. But I swear I've seen that before. :unsure:
Did the repair person reflow the interconnect header(s)?

Always start with -> Power and Connections.
 
And after you've checked power, remove each Pokey chip one at a time, and try booting the board into test mode (meaning power the cab up with the test switch already flipped on, which will force self-test to run). See if the list of errors changes when you remove each Pokey. Do NOT flip the game out of test mode. The Pokeys are the 40-pin chips at locations B/C2 and C/D2 on the aux board.

You need be VERY careful here, as any time a game board is misbehaving, you can very easily blow your monitor. But if you stick only to test mode in this case, you should be safe.

Power up first with one Pokey removed, then both. A blown Pokey can take down the bus, which could cause what you're seeing.
 
In case you want a puzzle to assemble



What vector collector said with the headers. They often get broken solder joints. Also reseating all socketed chips would be worth a try.
 
Okay, so I tested voltage on the PCB and ARII. The AR is giving me 9.6v at it's lowest possible trimmer pot setting, and the boards are getting 8.6v...not sure how to get that down to 5v?
 
UPDATE: Spoke to the repair guy and he says that if it truly was running at 8.6v, it'd be fried. Yet it's turning on and...playing great now??
Game plays fine, no errors? The voltage meter is still 8.6v?!

I'm so dang confused. I have to assume that my (brand new, got it today) multimeter is screwed up. Is it possible the game could run at 8.6v for any amount of time before being damaged? If not, then the multimeter must be faulty. Which would lead to another question: for testing purposes, is it safe to leave the game running for some time to see if the errors pop up again?

I've worked with computers a lot in life, and to some degree arcade machines, but not seen many as bipolar as this one...
 
Okay, so I tested voltage on the PCB and ARII. The AR is giving me 9.6v at it's lowest possible trimmer pot setting, and the boards are getting 8.6v...not sure how to get that down to 5v?
Are you sure you're measuring at the right spot? There is the 10.6VDC unregulated on the ARII you could be measuring by mistake instead.

Right spot to measure on the ARII would by across the C1 capacitor.

Test the AR II with the gameboard unplugged. If it actually is measuring 9.6V across C1 then definitely do not keep running it.

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Just measured it again across the C1...still showing as 9.6v :/ I'm measuring it with AC not DC, is that the right way? I also measured at the +Sense and get the same voltage reading. I also see the 10.3v spot, but I'm not measuring it there.
 
Just measured it again across the C1...still showing as 9.6v :/ I'm measuring it with AC not DC, is that the right way? I also measured at the +Sense and get the same voltage reading.
It's a DC voltage, you should be measuring with the DC setting on your meter.
 
Retest (with DC) showed 4.6, and I boosted it a little to 4.95. So voltage is good!

Appreciate the help and putting up with me. So far, the errors haven't shown back up today. But they do seem to come randomly, and in the form of almost completely jumbled graphics (save for the player and the player's projectiles). Putting it in test mode when it shows such issues always results a mathbox error and, as noted before, sometimes gets the full gamut of EQPM. And then the next day, it can function as normal again :poop: Not good for a setting where it needs to function consistently haha
 
Where are you measuring the 5V?

See post #4 above.

Measuring across the C1 capacitor; also measured at the +Sense! Both give me the same reading. Same thing at the +5v on the edge of the pcb near where the harness connects.
 
Measuring across the C1 capacitor; also measured at the +Sense! Both give me the same reading. Same thing at the +5v on the edge of the pcb near where the harness connects.


You need to be measuring on the test points on the game boards. (Both of them, main and aux separately).

If you are setting the voltage to 5.00V at the AR, it's going to be too low at the game boards. This is because there's about half a volt of loss in the wiring and connectors, which is normal and expected. So you always want to test it on the AR first (to make sure the AR isn't defective and outputting 10V on the +5V) before plugging in the game boards. But then you want to measure on both game boards, and set it so you have about 4.90-4.95 on the smaller (aux) game board, which should put the larger (main) game board around 5.10V give or take, if all of your connectors are clean.

The aux will always be slightly lower than the main, because the aux gets its 5V from the main, and you cannot adjust them separately. So you set the 5V so the aux is a little below 5V and the main is a little above. But it's critical that the aux be at least 4.90V. Right now the aux will be too low, if the AR is set to 5.00. The AR should end up around 5.5-5.75ish, when you dial in the game boards properly. But the AR value doesn't matter in the end, it's the value on the game boards that the chips actually see. So that's where you need to measure.
 
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