ARISTOCRAT Power Supply Feedback

 

 

MK5PFC

 

Can anyone tell me what is wrong with my model MK5PFC power supply? I replaced the shorted out Q5, C66 and C89 and I'm not getting start up. I'm only getting 149v off C52.

 

On the last property where I worked the MK6 power supplies kept burning out. Check your line voltages from the wall or outlet AC and if it has a ripple current more than +/- 2hz, I think, causes a cap to short the whole thing out. A good surge suppressor or ups and only 4 to a power outlet should get you through. Aristocrat called it a power issue. Also check your connections to the hopper/coin comp or printer/tracking interface. If there's a short in these, will cause it to go too.

 

I have 3 power supplies MK5PFC with no 24V output for the fluorescents. All 3 measure .72V. Wondering if you could tell me the quick fix or a brief circuit description?

 

Assuming that the rest of the supply is working and only the fluoro output is down, there could be an external short activating the over-current protection circuit. Power down the supply and disconnect the two fluoro plugs from the supply and wait about 20 seconds, then power it back up and see if the voltage is normal. If not, there may be fried components in the switcher output circuit for the fluoros, possibly the source resistor (R236) and/or the power MOSFET (Q7). Since the output is ~.72vdc, I suspect the 15 milliohm resistor is open.

 

Testing on the bench, run jumper wire from pin 1 of  X9 to one of the ground connections on the same connector 10 thru 14 on the MK5PFC power supply to get the 24v fluoro outputs to work.

 

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