qbert missing 30v and 5v help please.....

dudljoe

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So my qbert I'm building is missing 30v and 5v. I just installed the twisty wristy rebuild kit on the power supply board and had no change. So where should I start at from here has anyone ran into this issue before?
 
I think the power block has something to do with it. I tried 3 different power supplies in a friend's cabinet and +5 was dead on all of them.

the weird part was all the fuses were good. so I'm curious too.

unlike the Williams games I don't think you really NEED the power supply board. I'd dump that and use an Arcadeshop switcher adapter and call it a day.
 
So my qbert I'm building is missing 30v and 5v. I just installed the twisty wristy rebuild kit on the power supply board and had no change. So where should I start at from here has anyone ran into this issue before?

Did you accidentally switch the metal transistors?
The odd transistor stand off are they there?
The heat sink can shift around enough to short things out.

Is the voltages present on the input side of the power supply pcb?
The brick does have fuses you might want to check them.
 

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Transistors are in the correct positions I was careful to do them one at a time so I wouldn't mess it up. I'll check the voltages comeing into the board today and see where there at and yes I checked all fuses on power brick in bottom of the cabinet and on power supply board.
 
There should be an LED on your PCB that lights up to indicate 5 Volts. There are slight differences in some Qbert power supplies. Most indicate input voltage before the 11.5 volts are regulated down to 5V. R11 is the current limiting resistor for the 5 Volt LED. You should read about 11.5 Volts.

VR1 is small pot that you can adjust the 5 volts. If you have very little voltage and it does adjust up and down. Start looking at the bottle cap transistor q11. If there is no voltage adjustment i suspect U11.
 
Ok so checked thru the harnesses on the filter board and found a couple that were dirty cleaned them and then I'm getting 5v now but still missing 30v so we're should I begin and go backwards to find the missing 30v.
 
Ok checked at location D12 and am getting 5.01
 
Ok games is able to play and I checked the power brick all out and it is ok. I looked into just getting one of the 12v switcher kits and then realized if I just disconnect the 30v wire off the A3-J3 and spliced it into the 12v wire on the A3-J3 it would actually be doing the same thing that the switcher kit would be doing. So I tried it and it now has working sound I don't yet have the control panel done so I can't play thru to get the knocker to work but it should now be powered by the 12v. I don't believe doing this mod should hurt the components but if I'm wrong please correct me.
 
I believe the 7812 voltage regulator is capable of 1 amp.
This should run the amp and the main pcb. The knocker will draw a bit of current when it gets turned on..

If you fix the 30v you won't have this issue..

The fuse on the 12 volt is .25 amps on one side of the bridge rectifier and .25 amps on the other side of the input side of the bridge rectifier. This means you can only draw .25 amp before the fuse blows.

The knock has a 1 amp rating on fuse that it uses.
 
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I narrowed it down to the power supply. I read more on the arcadeshop switcher kit and went with it instead of messing with the original any further. More reliable and less chance of damage to any components. Everything is working great now on qbert.
 
did you install a 12VDC coil in the knocker bracket? I was going to suggest the AS switcher kit. That original supply was junk when it was new. That and all the filter board problems... ugh...
 
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