Tempest power help needed

OU Flight

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Trying to get my Tempest going. Here is the problem, game is not playing. Checked the voltages on the power brick and those checked ok. Voyages check good on ARII board. At PCB get the red LED lit that is next to the +5 test lug at top rear of board. For +5 I'm only reading 2.0. The +15 reads +15.

When I check the power for the +5 traced back to the socket on the ARII board it is only 2.0 there. If I unplug the wires from the ARII board the socket then reads +5. So it is obviously not holding the load. I tried a different PCB with the same results. Where to go from here?

Thanks
 
What happens when you turn up the +5 pot on the ARII? Usually it reads about +7.5 without the load and +5 with it...
 
Could it be something elsi also. I have tried 3 different ARII boards all with almost identical voltages?
 
I can rebuild it for you, or pick up a kit from bob Roberts.. Arcade shop sells them too..

I've got a kit from Bob just haven't done it yet. Figured I would test my other boards. Just weird if they all have the exact same problem. Or us that a common voltage to see with a bad one?
 
When I rebuild them should I use all the parts in the kit or just those that are bad?

This probably will not be the answer you want to hear, but that is really your call. Some people swear by rebuild kits (shotgunning a lot of parts) and other people ONLY replace bad parts. There are pros and cons to each.

Some of it depends on your soldering skills and your diagnostic/troubleshooting skills and tools.
 
That is it! They all test open. Thanks. When I rebuild them should I use all the parts in the kit or just those that are bad?

Thanks

My first plan of action would be to just replace R29 & R30 and retest. If the problem is then solved, I would pick the best A/R II and do a total rebuild.
 
Updated on this one. I'm an idiot. :) when it tested the resistors I did it completely wrong. Figured it out and they read r29 is 12 and r30 is 10.

Went back and double checked power at the brick. At the J5 connector I'm only getting 20 volts between pins 6 and 7.

What do I need to look at to get that voltage up? I put in a new big blue from Bob and a new bridge rectifier.

Thanks again
 
Ok got the AC voltage reading 36v now at the AR board. Cleaned the fuse block. Still only getting 2.5 volts DC out of it though.
 
On the 44 pin connector I get 5.78v at B, 2, and Y pins.

On the 30 pin connector no 5 v readings.

When I plug both connectors in the voltage drops to 1.78 to 2.0.

I just tried it with only the 44 pin connector and I get a reading of 5.78v on the main board now. Drops off when the 30 pin is plugged in.

Ideas?
 
disconnect the cp connector and retest for +5vdc on the aux board.

no change

additionally disconnect the coin door and retest on the aux board for +5vdc.

no change

Verify continuity between both edge connectors
 
With the control panel disconnected I get 5.37v on both boards now. It drops back off when reconnected. With it disconnected I didn't hear any game sounds like it was playing blind.

I also have a monitor issue but I'll deal with that after getting this one fixed. I get neck glow but the led on deflection board isn't lit and no chatter. Screen is blank.

Do I have a short in the control panel somewhere that is pulling down the voltage? With the CP disconnected the game should go ahead and start up, correct? So I should hear something right?

Thanks again
 
You either have a stuck switch or a short in the cp. I would suspect one of the start switch diodes is blown or a bad coin lockout coil.

Disconnect the lockout coils first and test again.

no change

disconnect the start switches one at a time and retest.

no change

disconnect the slam switch and retest
 
Thanks for all your help Dokert. I would have never thought the problem would be in the control panel. It ends up the #2 start switch is bad. I unplugged it and now get 5 volts on the boards. I also found a bad fuse on the monitor deflection board.

Following the flow chart on the kfu.com website I'm down to a problem with the CPU it looks like. I have solid light on the start button, no sounds, both LEDs lit on the monitor deflection board with just the spot on the screen if I turn up the brightness. Tried going into test mode and nothing happens. I'll try resetting all the socketed chips on the boards tomorrow. Maybe that will help.

I've have two board sets too. Same results with both sets.
 
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