Tempest Volume Pot

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Hey, does anyone know where to get a replacement rheostat for the volume control on a Tempest? I only see a part number but no specs in the user manual.
 
Here's a starting point for you ... 50Kohm rheo. Or is it 50ohm? @andrewb

ANSWER: It's 50ohm. Just confirmed on my Tempest upright (and also noted in the cocktail manual).
So, don't believe everything you read ... but some Atari games do use the higher Kohm POTs.
Depends if the volume POT is wired pre or post AMP. (PRE-AMP: higher R value, lower power; POST-AMP: lower R value, higher power).
Consult the manual when possible.

50R_Tempest_VOLPOT.jpg


 
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I'll sell you a new one for $30 (+shipping) but I won't be able to put my hands on it until the end of the month.
 
Oh, you can search for it by part number. It's an Ohmite RES50RE.
 
Yeah, it's very unlikely the one you have can't be salvaged and cleaned/repaired if needed. They are simple devices. Only if it were completely shattered or missing would you need to buy a new one.

What is wrong with yours?
 
Ok, I'll try cleaning it. Volume is pretty much either low or non-existent depending on the setting, Andrew.
 
If that's the case, it's probably not the pot.

Have you swapped out the AR board? If you have any other AR-II-02 or -04, you can try it in the Tempest.

It could also be a bad LM324 on the game board. Or a bad speaker or wiring connection, theoretically. However the best thing to do is to test.

To test the pot, wiring, and speaker, take a DMM, unplug the 4-pin speaker connector from the AR. With cab power off, put the DMM in ohms mode, and measure the resistance looking into the cab harness, on the two pins of the 4-pin connector that have wires connected to them. (There are only two.)

Measure the resistance, and vary the pot from one extreme to the other, and note the max and min resistance values. Post the max and min resistance values here. That will tell us if the pot, wiring, and speaker are ok or not.
 
Ok, it's not the pot or the LM 324- Resistance values are good and when I swapped out a different ARII board, everything worked.
 
So your issue is "no sound"? That's why you were originally asking about the rheo?

Check the leads of the TDA2002 amps on the ARII ... sometimes due to mechanical stress, they break.
Otherwise, consider replacing them

Don't do a cap kit on your faulty ARII (unless the caps look physically damaged).
 
What were the resistance values?

Replace both TDA2002's on the AR. That should do it. As VC said, do not recap it, it isn't necessary. Keep everything else nice and original.
 
Ok, I'll try that. I got a pretty good range- 8 to 48 Ohms. Thanks. VC- I was getting sound but it wasn't very loud.
 
Ok, I'll try that. I got a pretty good range- 8 to 48 Ohms. Thanks. VC- I was getting sound but it wasn't very loud.


Ok. 8 to 48 is perfect. On the low end you should be measuring the speaker (which I think is 4 ohms? It's either 4 or 8), plus a few ohms for the harness wire.

On the high end, you should measure the above, plus the full resistance of the pot. It's a 50-ohm pot, but the tolerance is likely 10%. So they could be anywhere from 45 to 55, or maybe even more.

But as long as you get something like 5ish to 50ish ohms when you measure the whole system, you know the pot, speaker, and wiring are all intact and generally ok, all in one simple DMM test.
 
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