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Power supply/isolation transformer combo
Question from Cameron: I’m working on a 1993 Midway NBA Jam TE cab that appears to have the fabled isolation transformer/switching power supply combo. AC lines run into it from an AC filter. It should isolate 120 v for the monitor and 120 v for the switching power supply, as well as 5.9 for the coin door lights and what the schematic seems not to want to specify for the light fixture. I need to know how to replace this part or if i even need to. It takes 119.6 v and puts out 132 v to the monitor and switching supply. the switching supply (brand new on I put in) will not light up and takes that 132 v AC and puts out DC – .6v for the -5v and 1.96v for the +5v and then like 2v for the +12v. These are the same on the jamma harness and the CPU doesn’t light up either. will replacing that combo unit with one that puts out 120 fix this issue and give power to the CPU again? Also the monitor comes on now that I stuck a cap kit in it, but–I think because of the 132 v coming to it– it shows up solid white. This may also be because there is no signal from the board.
1 answer
Response from Jonathan: Cameron,
We received your email and your voicemail but couldn’t get a hold of you on the phone so we are writing this email in response to your question. Sounds like you are having some wiring trouble. The best advice we can give you is to get a new power supply and perhaps even a new isolation transformer and rewire your cabinet. You can order these part from Bob Roberts (http://www.therealbobroberts.net) for fairly cheap. We believe that Bob also sells a complete cabinet bottom which includes the power cord, isolation transformer, power supply and more for one price. This might be a better way to go if you don’t want to fool with wiring that yourself. Check out our posts on Checking And Replacing A Power Supply and Checking A Classic Power Supply for more information.
We have also featured your question on episode 14 of our Q&A podcast. Please listen to it for more of our thoughts on your question. Thank you for your question and keep us updated on your progress.
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