Electronics > Repair

Another Yeehaa 3010d 30V 10A PSU fault.

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Chris Roubis:
I bought one of these YIHUA 3010D

Wondering if its worth modding to a higher current rating.

BradC:

--- Quote from: Chris Roubis on July 26, 2020, 09:08:14 am ---I bought one of these YIHUA 3010D

Wondering if its worth modding to a higher current rating.

--- End quote ---

No. If it's a "genuine" Yihua then the transformer is good for 10A continuous. If it's a cheaper clone then it's good for 10A until the transformer melts. If you try and mod the Yihua for more current it'll be good for > 10A until the transformer melts.

BradC:
The "Genuine" Yihua power supply shorted an output transistor while charging a 150AH Lead acid battery.

It then proceeded to pump maximum current into the battery for > 12 hours limited pretty much by the resistance of the leads between the battery and charger.
When I found it, it was around 14A and the voltage at the PSU was ~18V, so 252W. Within the rating of the transformer, but ~40% over the rated secondary winding current.

No bad smells from the transformer, but cooked the current sense resistor and melted the front panel and binding post nuts. Due to there being very little dissipation through the heatsink, the whole thing was warm but not excessively. The battery wasn't so lucky.

While it was a "fail", it indicated the bits that didn't fail are nicely rated for purpose (transformer, rectifier and so on). The PCB and relays had been "upgraded" a couple of years ago due to a burned track, so all secondary side power handling had already been beefed up.

I replaced the BUX48A output transistors with MJ15003s and replaced the Emitter resistors with R0.22 rather than the R0.1 that were there and replaced the silicone insulators with greased mica. Wonder what will fail next time? The "heatsink" is really the weak point on these things.

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