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SPD3303X Hiccup
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ArcticGeek:
I tend to think that this might be a good candidate for a MOSFET-based bridge rectifier in order to reduce the heat dissipation, like what is shown here:

https://www.powerelectronictips.com/power-supply-circuit-mosfet-bridge-rectifier-gives-high-efficiency-for-low-voltage-high-current-ac-dc-supplies/

It would require a small PCB to be etched to hold the MOSFETs and other components.  I actually sold my SPD3303X-E some time ago, but if I still had it I would be tempted to make up a small board to replace the bridge.  This would get rid of the heat almost completely so you wouldn't have to worry about surrounding parts getting too warm.

Food for thought.

Cheers,
tautech:

--- Quote from: ArcticGeek on September 29, 2024, 12:04:14 am ---I tend to think that this might be a good candidate for a MOSFET-based bridge rectifier in order to reduce the heat dissipation, like what is shown here:

https://www.powerelectronictips.com/power-supply-circuit-mosfet-bridge-rectifier-gives-high-efficiency-for-low-voltage-high-current-ac-dc-supplies/

It would require a small PCB to be etched to hold the MOSFETs and other components.  I actually sold my SPD3303X-E some time ago, but if I still had it I would be tempted to make up a small board to replace the bridge.  This would get rid of the heat almost completely so you wouldn't have to worry about surrounding parts getting too warm.

Food for thought.

--- End quote ---
OTOH, any diode or bridge run near to max rating will produce heat.
Like most design these days components get pushed where once designers were much more conservative....which aided longevity/reliability.

Instead of a 2A rated bridge, latest HW runs an inline package of maybe double the rating...maybe pics I took of them display the device # IDK.

Edit to add
The updated inline bridge in a unit I have here is KBU1010, a 10A 1kV bridge.
https://www.mouser.com/datasheet/2/1451/kbu1010-3477620.pdf
mawyatt:
We replaced the OEM rectifier with a 4A version that's in a flat plastic pack (like the new PCB version). Bent the leads to arrange them like the OEM version and fit directly to PC. This is higher off the PCB but should give better thermal results than the smaller circular OEM bridge rectifier.

Getting the OEM rectifier out was the most difficult part, everything else wasn't difficult. These things are built like tanks and not difficult to disassemble. The banana sockets are solid chunks of metal bolted directly to the PCB, looks like they could handle 100s of amps, it's a shame they didn't get the socket depth and spacing correct. Hopefully the new 4000 series fixed this, but hope they kept the massive metal shaft that bolts to PCB connection. 

Results are OK so far, will let run for a few days/weeks.

Best,
tautech:

--- Quote from: mawyatt on September 29, 2024, 03:01:56 am ---We replaced the OEM rectifier with a 4A version that's in a flat plastic pack (like the new PCB version). Bent the leads to arrange them like the OEM version and fit directly to PC. This is higher off the PCB but should give better thermal results than the smaller circular OEM bridge rectifier.

--- End quote ---
Yes this was the HQ recommended rework method that while very achievable, is an ugly bodge IMO and very never keen on it, so have always fastened the bridge remotely and made a short wire loom to it.

Others might like to see any pics Mike unless it's already a closed case......
mawyatt:
Didn't look that bad. It's all closed up now and back on rack.

Best,
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