I am working on bringing a Williams Lucky Seven back to life. It has no audio board, just chimes. I put in a known work MPU, a known working driver board and an aftermarket power supply. Upon power up, there was a continuous loud hum coming from thepower supply board. I powered it down and swapped in the original power supply board, which had no visible damage. It too produced a hum when powered up. What could be causing this? What should I check first?
On Friday, June 18, 2021 at 7:13:26 PM UTC-4, Zap wrote:power supply board. I powered it down and swapped in the original power supply board, which had no visible damage. It too produced a hum when powered up. What could be causing this? What should I check first?
I am working on bringing a Williams Lucky Seven back to life. It has no audio board, just chimes. I put in a known work MPU, a known working driver board and an aftermarket power supply. Upon power up, there was a continuous loud hum coming from the
I disconnected power supply board from the transformer, and still had the hum. It is the transformer humming, not the power supply board. My old ears deceived me. What can I do about it? Is this a sign the transformer is going bad?
John,opportunity for a short. After running for 5 minutes with no load, transformer felt barely above ambient temperature. I would not even call it warm.
Fuses good and correct rating. Playfield and backbox lightning do not go through the power supply board, and they are good. Transformer seems solid in yoke. it does not move at all. Wiring is intact, properly insulated, and I did not see any
Has anybody ever run into a transformer that just hums? I might even go so far as to say it buzzes.
Thanks,
Zap
John,
Everything is tight. I tried an unorthodox method which some people had success using. I whacked it with a hammer. All that did was scuff the top of the plates.
At this point, since it functions more or less properly, I will live with it as is.
I do appreciate the help.
Thanks for taking the time to respond!
Sincerely,
Zap
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