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Old 24th Jul 2022, 6:17 pm   #3
Chrispy57
Hexode
 
Join Date: Mar 2020
Location: Rochdale, Greater Manchester, UK.
Posts: 440
Default Re: Broken Tenma supply

Don't like to see a post with zero responses, although I'm not familiar with this unit, perhaps a common-sense approach may take you a bit further on your fault-finding journey. The photo shows a dead unit, any led or fan activity when powered on?

"Already checked the fuses" - is there one in the primary of the mains transformer, thermal fuse, Worth a resistance check of the primary first? The transformer looks like it has two identical sets of secondaries, you could unplug them and check and compare resistance readings? Apply mains and check secondary voltages with plugs disconnected from pcb. Reconnect plugs, any voltages on the rectifier diodes and smoothing capacitors

Looks like a few relays in there, check coil resistances. Could be the output transistors as you suggest, but all blowing at once seems a bit unlikely, sounds like something common to both channels involving the above components.

Good luck
Chris
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