The rectifier diodes for input AC to DC array upper left, two small heatsinks, TO220 transistors for chopper, outputs are diode rectifier in TO220 package and two soldered together diodes on heatsink is not rated for 230W and pair of main capacitors is undersized. 100W or less is about right. If used for 486 computer, that will do fine, same with pentium computer.
The fan is cheap type as it has no flange to save on material.

4 legged filter inductor and capacitors left off.

Cheers,

pentiumspeed wrote on 2022-11-29, 23:28:

The rectifier diodes for input AC to DC array upper left, two small heatsinks, TO220 transistors for chopper, outputs are diode […]
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The rectifier diodes for input AC to DC array upper left, two small heatsinks, TO220 transistors for chopper, outputs are diode rectifier in TO220 package and two soldered together diodes on heatsink is not rated for 230W and pair of main capacitors is undersized. 100W or less is about right. If used for 486 computer, that will do fine, same with pentium computer.
The fan is cheap type as it has no flange to save on material.

4 legged filter inductor and capacitors left off.

Cheers,

Thank you. The two big caps are 200V / 330 uF and rated to 85 C, off brand "Viva"... some of the other caps are brand name ( Rubycon)

This is from a k6-2. At least the board also has ATX connector, so I can readily use something modern that I have laying around. Ill keep this as an emergency backup PSU for my 386/486.

That psu can do 120W, sure.

But... no proper EMI input filtering. Only has two non safety rated caps at YC1, YC2.

EI33 main transformer and output common coil in that size can do 150W at 60-70C temperatures.

The output rectifiers really hint at the max power. Looks like a 20A doube diode in TO220 package for the 5V rail. Two 3A diode combined for the 12V rail.
With 70% average efficency the realistic power output for the 5V rail is 15A and 4A for the 12V rail.

Looks like Q6, R60, R50, RTC2 could make up a temperature sensing fan controller circuit.

Set to who knows what power limit, as that 494 pwm and lm339 may and may not be configured to shut off the psu at 150W or 200W or 250W or until the casing melts...

The electrolitic capacitors are old so that might be a problem.

As pentiumspeed pointed out this unit is about cutting costs. If one would replace the parts with higher rated ones, add the missing components and set the up protections and pwm control proper, it would make this a way better AT psu.

Ah yes, el cheapo DEER unit.

I have one of those as a testing AT unit. At best I bet it can do 120W but that's a stretch.
Mine is recapped and with the 12v diodes substituted for a proper 12v rectifier - I forgot what it was but probably either a 12, 16 or 20A @ 60V part I had from a junk pile - you might definitely want to upgrade those two rectifiers quite a little for the 5 and 12v lines.

DAVE86 wrote on 2022-11-30, 10:32:

That psu can do 120W, sure. […]
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That psu can do 120W, sure.

But... no proper EMI input filtering. Only has two non safety rated caps at YC1, YC2.

EI33 main transformer and output common coil in that size can do 150W at 60-70C temperatures.

The output rectifiers really hint at the max power. Looks like a 20A doube diode in TO220 package for the 5V rail. Two 3A diode combined for the 12V rail.
With 70% average efficency the realistic power output for the 5V rail is 15A and 4A for the 12V rail.

Looks like Q6, R60, R50, RTC2 could make up a temperature sensing fan controller circuit.

Set to who knows what power limit, as that 494 pwm and lm339 may and may not be configured to shut off the psu at 150W or 200W or 250W or until the casing melts...

The electrolitic capacitors are old so that might be a problem.

As pentiumspeed pointed out this unit is about cutting costs. If one would replace the parts with higher rated ones, add the missing components and set the up protections and pwm control proper, it would make this a way better AT psu.

PcBytes wrote on 2022-11-30, 13:14:

Ah yes, el cheapo DEER unit.

I have one of those as a testing AT unit. At best I bet it can do 120W but that's a stretch.
Mine is recapped and with the 12v diodes substituted for a proper 12v rectifier - I forgot what it was but probably either a 12, 16 or 20A @ 60V part I had from a junk pile - you might definitely want to upgrade those two rectifiers quite a little for the 5 and 12v lines.

Thanks, you guys are the best.

PcBytes wrote on 2022-11-30, 13:14:

Mine is recapped and with the 12v diodes substituted for a proper 12v rectifier - I forgot what it was but probably either a 12, 16 or 20A @ 60V part I had from a junk pile - you might definitely want to upgrade those two rectifiers quite a little for the 5 and 12v lines.

Yeah. Any TO220 ultra or super fast double diode will do, SR1620CT, 20100 maybe 2060 (STTH or MUR too) Just avoid schtottky diodes, those would be too fast. For 5v rectification schottky is ok. Go crazy like MBR60100 in TO-247.
No need to touch the live primary side either if nothing is failing, just beef up the secondary.

Seems like none of the more important electrolytics are Rubycons, they would have "K" shaped vents in this case.
There also existed fake Rubycons labeled "Rulycon".

DAVE86 wrote on 2022-11-30, 16:08:

PcBytes wrote on 2022-11-30, 13:14:

Mine is recapped and with the 12v diodes substituted for a proper 12v rectifier - I forgot what it was but probably either a 12, 16 or 20A @ 60V part I had from a junk pile - you might definitely want to upgrade those two rectifiers quite a little for the 5 and 12v lines.

Yeah. Any TO220 ultra or super fast double diode will do, SR1620CT, 20100 maybe 2060 (STTH or MUR too) Just avoid schtottky diodes, those would be too fast. For 5v rectification schottky is ok. Go crazy like MBR60100 in TO-247.
No need to touch the live primary side either if nothing is failing, just beef up the secondary.

Actually, just for his case, I'd replace the primaries too. VIVA caps have an worse than horrible reputation, and they were the most common caps found in Deer PSUs, on the primary sides.

I will populate the missing components of the filter on
the primary side, and replace those "Y" caps with proper ones too.