Help with troubleshooting a Dead PSU

[freddiefiasco]

After playing on my MT3 cabinet, my PSU finally died. I tested voltage on the following lines:

DC Outputs:
+12V: Reads 3.844V
+3.3V: Reads 0.266-0.277V
+5V: Reads 0.000V

AC Output:
120V: Reads 121.8V

PSU: VG88-11121-01

The PSU houses two potentiometers (+3.3V/+5V) on the back side where the power cables are attached to the PSU case. I had them at the correct voltages before death so I may hesitate to adjust this knowing the voltage readings are so low.

My next steps are to open up the case and clean out the dust and years of use.
After that, I want to say I need to replace the capacitors.

Are there other checks I should be doing before making an inventory of the capacitors to replace in this PSU?

I know the simple answer would be to replace this with a new one (New ones are between $114 and $144 online) but I think I would like to make this journey to resurrect this PSU if at all possible.

Given the risks, I would also make sure to be careful dealing with this repair.

Edit: Fan on the PSU never worked but I assumed it only kicked in when necessary but I don't think this PSU is that fancy.

 

[twistedsymphony]

I'm not an expert on PSUs, I usually just replace the caps and hope for the best.

the non-working fan leads me to believe this might not be a cap issue though. it's possible the lack of airflow caused something (perhaps the voltage regulator) to overheat and burn out. look for discoloration around the solder points, if you have an IR thermometer you can also check the temperature of various components while running and see what gets hot.

I've never seen arcade cabinet or PSU fan with speed control, they generally run at 100% speed all the time because they're in a huge box in a noisy environment anyway, even speed control on a PCB is rare for this reason.

 

[freddiefiasco]

Cool thanks! I have an IR gun. I will use that.

 

[freddiefiasco]

I'm not an expert on PSUs, I usually just replace the caps and hope for the best

Since the PSU is completely DOA I might as well replace them all. So I will be cleaning it and taking inventory of all the caps to replace.

the non-working fan leads me to believe this might not be a cap issue though. it's possible the lack of airflow caused something (perhaps the voltage regulator) to overheat and burn out.

Some sort of good news on this front, just for curiosity's sake, I popped open the cover to the PSU and nudged the fan blade and oddly, the fan blades refused to move. I've never seen this happen before, usually they're just really fluid and you can push them with a paper clip or your finger. When I tried to move the blades, it took a bit of pressure just to make it spin move. So I powered up the PSU and used my meter on the red/black wires and i get a reading of 3.8V when turned on. So I'm hoping a cap kit will provide a remedy to this PSU without additional tinkering.

Thanks again for your insight.