Hi all,
I have a Topward 6306D power supply and recently it started on making violent transformer noise (yes, it did it itself while I was away
, there was no load connected to the outputs..). So I opened up the cover and took a look, everything looked fine. All functions worked well (voltage, current...) except that the transformer which buzzed like a grinder.
Here are some pics for the 6603A which have very identical boards
http://www.kerrywong.com/2012/12/01/topward-6603a-linear-power-supply-teardown/There were 2 packs of wire from the transformer which went to each channels. Each pack had 5 thick wires which were soldered directly to the heavy traces (top in pictured). The rest 6 thin wires were to connector on board (top right corner).
I measured the 5 thick wires continuity and they seemed to be shorted together. The same is true for the other channel. I wonder if this way is the way it is ...?
I disconnected as many connectors from transformer to PCB as I could, powered up, still buzzed..
So I am planning to desolder those 5 thick wires off the PCB to see what happens . But before I do that, can you please offer your opinions on troubleshooting this PS ?
Thanks.