Jackpot Stampede Deluxe PDU board circuit diagram/schematic?

[MartolFart]

With the help of this site, I was able to get this machine going again, first with a replacement power supply board and then with an ATX power supply (currently temporarily connected).... So now I have two of these failed boards (the +/-12VDC and 5VDC supply) I'd like to try and repair with hopefully more robust components and so I'm trying to pull together everything I can find, specifically, a circuit diagram/schematic would be a most helpful starting point. I've scoured this site and the web and found details included in the conversion posts (including a very helpful WMS PDU diagram), but haven't found anything specific to this board, so would like any help the veterans here may be able provide? Thanks in advance!!

[MartolFart]

So interestingly (to me anyway....), the info on the transformer (there's really only one with this switcher?!, the other thing that sorta looks like an xformer is an input filter) indicates this supply is actually a power "converter" (AC to DC) type number NFS110 (mfg Artesyn, Astec, Emerson, et al) model 7601 (5VDC, +/- 12 VDC). I would have thought that label was transformer detail and didn't really pay much attention until I started trying to figure out the circuit..... So I guess I'm really looking for a Computer Products (relabelled Artesyn/Emerson I suspect) NFS110-7601 schematic, although I think any NFS 110 circuit diagram would be helpful. Again, really appreciate any help you guys can provide! 

[MartolFart]

Initial PD indicates power is good up to bulk capacitor (330uF, can't tell from the CB what the component number is) with 165VDC present.... (and hoping I remember to drain it!) I think the chopper MOSFET tests good, so I'm (barely) into looking at this discrete (no IC!) pulse width modulation circuit which I initially suspect has problems.... Again points to the need for a schematic to figure out what's going wrong.....   

[MartolFart]

Hmmm.... Looks like I'm kinda on my own here at least so far.... So... I've found zilch on NFS 110 and apparently Artesyn is jealously guarding their "IP" for this ancient technology circa late 80s early 90s.... Attached diagram is sorta close to the same topology I think, only lacking the several TL431 which are programmable zenners...


Was waiting on a 100x scope probe to help with diagnostic measurement (I didn't trust my breadboarded divider readings, turns out they were pretty close....). I pulled the bulk 330 uF and the IRF840 and they both tested good out of circuit (as expected).


Current thinking is something on the output has the PWM/drive circuit shut down?  Conventional wisdom sez prolly bad (dried up) electrolytic so shotgun all of them with tantalums. So need to order em up.... If it fires up then maybe think about putting some cooling on the PDU.


Thought from gray beards out there?

[Sunrise Side]

Recapping in most cases resolved many PS failures.