Testing Voltages - Tempest

[Snakebyte]

I recently picked up a non-working Tempest cabinet.

I've found a couple really good troubleshooting guides online.  I've gone through the guides up to the point where it asks to test voltages.

In the guide it seems to want you to use an oscilloscope rather than a standard volt meter.  Am I going to damage anything by testing with just a standard run-of-the-mill meter?  Am I wasting my time using a meter at all?

The guides seem to ask to test voltages at the PCB.  I have not found a single diagram that shows the voltages from the power supply, which really would be my preferred method of testing.

Anyone have any ideas or input?

Thanks

[grantspain]

a standard multimeter is perfect but first you need to know what voltages are expected,i would imagine +5,+12 and poss -5
whats the problem with the machine?

[Snakebyte]

a standard multimeter is perfect but first you need to know what voltages are expected,i would imagine +5,+12 and poss -5
whats the problem with the machine?

The board is labeled with the voltages so knowing what to expect shouldn't be a problem.  I really do wish there was a diagram some place that shows the voltages at the connector.

When you power it on, the (diagnostic?) lights on the board and monitor chasis come on.  The coin door lights come on and you can hear the sound amp hum when you turn the volume up all the way.  The player 1 and 2 buttons light up solid but do not flash.  I *think* I have the game set in free play currently so the player 1 and 2 buttons should be flashing.

The game doesn't produce any sound or video

I'm hoping it's just a bad power supply which is why I need to test the voltages, but who knows!

[grantspain]

it does sound like a bad psu,but first meter those voltages(if you get them its probably a board fault)
all you need is a pinout of the tempest board,i bet someone on this forum knows

[Snakebyte]

it does sound like a bad psu,but first meter those voltages(if you get them its probably a board fault)
all you need is a pinout of the tempest board,i bet someone on this forum knows

I actually did find a pinout chart.  My main concern is that it specifically states that it is for a cabaret cabinet.  I really doubt there's any change between the different cabinet types.  I'll give it a shot when I get home.

In case anyone is interested, the pinouts I found were from

http://www.ggdb.com/KB.aspx?c=Coin-Op&s=Arcade&vid=3057&kb=209

[grantspain]

i looked at the pinouts,looks perfectly straight forward
return denotes your dc common
there are some wierd voltages on it though this must be a very old machine

[RayB]

I've worked on 3 different Atari games, so maybe my GUESSING here will be relevant:

First, check all fuses (and fuse holders)

Next, the board should have little metal loops sticking out of it all over the place. These are test points. They will have labels printed next to them. All you need to do is test voltage at those points. You place one test probe to a point marked "GND" and the other to one marked with a voltage value. THe ones you want to test will likely be +5v, +12v, and/or +22 . If any of these are off by more than 1 +or-  then the voltage on the AR-II board must be adjusted or the AR-II board needs repair.

The AR-II board will also have test points on it. But be careful... Some of them are AC, so make sure you set your meter to correct measuring setting.

That's about it really. If your game board shows "normal" readings for +5 and the +12, then your power is good. Check your TEST SWITCH (usually next to the volume knob). Place the test switch into "on" position and you will hear beeps if your game board is not working correctly. (Download the Tempest manual to find out about the Test Mode).

[Snakebyte]

I've worked on 3 different Atari games, so maybe my GUESSING here will be relevant:

First, check all fuses (and fuse holders)

Next, the board should have little metal loops sticking out of it all over the place. These are test points. They will have labels printed next to them. All you need to do is test voltage at those points. You place one test probe to a point marked "GND" and the other to one marked with a voltage value. THe ones you want to test will likely be +5v, +12v, and/or +22 . If any of these are off by more than 1 +or-  then the voltage on the AR-II board must be adjusted or the AR-II board needs repair.

The AR-II board will also have test points on it. But be careful... Some of them are AC, so make sure you set your meter to correct measuring setting.

That's about it really. If your game board shows "normal" readings for +5 and the +12, then your power is good. Check your TEST SWITCH (usually next to the volume knob). Place the test switch into "on" position and you will hear beeps if your game board is not working correctly. (Download the Tempest manual to find out about the Test Mode).

I've gone through the test procedure listed in the Tempest manual.  No luck with any beeps coming from the game.  Since I was too lazy to pull the board out and find my volt meter I tried throwing the game into test mode first.

I did test the fuses and holders, those are in good shape.

I still haven't had a chance to test the voltages.  I figured I'd test at the board connector first since I found the pinout and then go to the actual game board afterwards.

Maybe today, hopefully today I'll be able to test everything.

[RayB]

Well keep in mind, what matters most is how much juice the BOARD is getting. So testing at the test points I mentioned is all you need to do.

Also remove the board connector and clean the contacts with a pink eraser (till they SHINE).

My Missile Command did the same thing as you when I got it. Both player lights were on and nothing on the screen. The voltages from the AR-II were wacky. So I took the safe route and replaced the Big Blue capacitor on the power supply, and did a rebuild kit on the AR-II (purchased from Bob Roberts). Then I just got a board that was tested working and sold off the non-working game boards I had.

[Snakebyte]

I was finally able to test the voltages at the board last night.  Everything was withing a tenth of a volt of where it should be.  Nothing was fluctuating.

I'm not quite sure what the AR-II is or where it's located.  Is that the audio amp or the actual power supply with the big blue?

This is a cocktail cabinet so it sounds like I may have to remove the power supply to do any testing on it.

Hopefully I'll have some more time this weekend to do some more poking around.

It was dark when I did the work otherwise I would have taken some pictures
Working by flashlight isn't all that much fun either.

[RayB]

The AR-II is both an Audio amp and a voltage regulator. It's the smaller board in there.

If voltages are GOOD at the board, I'd say stop there... Don't bother with the power supply or anything like that. You have a board problem (game board).

Look for broken legs, loose components, burnt up resistors or cracked capacitors. Remove the connector and clean the edge traces till they shine (especially if the first couple look burnt). Put the connector back on nice and tight.

Power on. Put the game's test switch to ON, and turn up the volume. Do you hear beeps?

[RayB]

OH and what was your voltage on the +5 ? Sometimes some games need a little more juice... Like 5.2 or even 5.4. I would try to find someone who owns a Tempest and find out what their +5 measures exactly....