Sanwa JVS PSU making ticking sound, seems dead :(

[kazuo]

Picked up this Sanwa JVS PSU for Model 3 boards from YAJ, and seems like it's actually "junk"... it ticks when it's powered on, and doesn't seem to work properly. A visual inspection doesn't reveal anything obviously wrong: caps look fine, no burn marks, no mysterious fluids, no apparent corrosion or other damage that might indicate a bad trace, for example. I haven't removed it yet to check for cold joints, but the ticking leads me to believe that likely isn't the problem. I checked the fuse and it has continuity, so I ruled that out right away. I tried a different power cable (I have several!), and I got the same symptoms. The PSU ticks whether or not it is connected to a board. I think the ticking might be coming from around the area near the 3 regulators and the coils.

I don't have a diagram of how this thing is wired up, but I think you can probably guess based on the wire colors for the harness what is what (12V Yellow, 3.3V Brown/Orange, 5V Red). The pin for 5V (with the red wire) is reading ~3V, and every other pin is reading under 1V. Adjusting the pots didn't seem to make any change in the voltage. I'm far from an expert in general, and I haven't really worked on power supplies before, so any help is appreciated!

Full-size

Full-size

 

[kazuo]

Found the pinout on TOPS website. EDIT: My original guess for the wiring was wrong, it seems like it's actually Red is 12V, Brown is 3.3V, Yellow is 5V. So I guess really I was reading ~3V on the 12V rail (with no load).

 

[kazuo]

Been messing with this on and off since I made this thread. Found some weird stuff with a diode or two and the 12/5/3V regulators, but ultimately ended up being dead ends when I compared it to the working PSU I also have. I tried pulling a small load on the 5V rail, no change, still dead. I ordered a cap kit on the off-chance that it fixes the problem, but I'm not holding my breath.

If you're following along and you're good at or you know someone good at PSU repair, send me a DM!

 

[awbacon1]

Found the pinout on TOPS website. EDIT: My original guess for the wiring was wrong, it seems like it's actually Red is 12V, Brown is 3.3V, Yellow is 5V. So I guess really I was reading ~3V on the 12V rail (with no load).

red is 12V? thats just weird

 

[nem]

That's standard coloring for all Sega cabs. +5V yellow, +12V red, +3.3V brown.

 

[awbacon1]

That's standard coloring for all Sega cabs. +5V yellow, +12V red, +3.3V brown.

Haha I should have been specific...i find their decision to do that odd.

Red in my kind is the universal color for 5V the same way black is universally ground

 

[nem]

Oh yeah, GND is white. That too.

 

[twistedsymphony]

The PSU ticks whether or not it is connected to a board. I think the ticking might be coming from around the area near the 3 regulators and the coils.

are you feeding this 100V or 120V.

Some Japanese PSUs do not support 120V and will only work properly at 100V (Such as the Taito/Wei-Ya PSU used in the Vewlix and some Egrets)

 

[jassin000]

Some Japanese PSUs do not support 120V and will only work properly at 100V (Such as the Taito/Wei-Ya PSU used in the Vewlix and some Egrets)

That big time.
I killed the audio amp on a JAMMA PCB this way (ie Wei-Ya 12v is unstable with 120v input).

 

[nem]

It's a Mean Well. It's 100-120V. It can even be switched to 200-240V.

 

[awbacon1]

Oh yeah, GND is white. That too.

yeah that'll always just seem wrong to me haha

 

[kazuo]

are you feeding this 100V or 120V.

Some Japanese PSUs do not support 120V and will only work properly at 100V (Such as the Taito/Wei-Ya PSU used in the Vewlix and some Egrets)

120V. As @nem pointed out, this is a rebranded Mean Well PSU manufactured for Sanwa (SWN-JVS IIRC), 120V is fine and within spec. I have another one I've been using at 120V for ages without any issues. The input voltage isn't the problem.

 

[kazuo]

I realized I never followed up here for posterity, but... it got fixed! Not by me, though.

I sent it off to Sharp Image Repair in Las Vegas, and they did... I have no idea what they did, other than a full recap (since that part was obvious), but it has worked perfectly since I got it back.