Rottendog PSU for Williams system 7

[Andy_B]

Hi,

I have just fired Pharaoh up for the first time. It's got a Rottendog PSB fitted but, with everything plugged in and fuses fitted, I'm only getting GI and nothing at the PSB test points (+12, -12 and +5).

Before I start this journey does anyone have any experience with these boards?

I'm happy to persevere but there are a number of bad reviews on these products and little in the way of documentation.

I'd be interested in a non-working original If anyone has one - as long as it's not roached
Andy

 

[lukewells]

The main problem with those Rottendog PSU's is the display voltage sections, they can self-destruct if there is a bad connection on the display power pins, or if the game is powered up with the displays disconnected. The 5v section seems work work reasonably well.

If you don't have any of the main voltages (5, +12, -12) then first check the AC voltages coming into the board and the related input fuses first, as you should have at least one of them.

If I remember rightly, back in the day, they used to send out a paper copy of the schematics with the psu's and so I should have them somewhere, but the chance of me finding them is like 1 in a million

 

[lukewells]

I found someone else had posted an image of the schematics. Check F1 as that would cause the loss of +5 / + 12 / -12

 

[lukewells]

If F1 is blowing, check for shorts on D501-D504 or the 5v regulator

 

[Fantazia2]

.

 

[myPinballs]

In my view, dont bother with this power psu unless you have a led display in it. The hv design is terrible..

 

[Andy_B]

I checked fuses and none were blown. I'll have another look in the morning.

Powering up without displays connected destroys the HV section? - what a quality design!!!

The more I learn the less motivated I am to proceed with this. Posting a wanted ad

 

[Andy_B]

Unplugged everything from the Rottendog and the 5v and 12v is back up.

Tested the cpu and driver on the bench with the trusty Amiga PSU and the board boots.

Will plug things in one by one next.