Williams System 11 Power Supply Issues

R3LL1K

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Rebuilt the power supply by replacing every component on PS board with the exception of some transistors and diodes which tested working. All voltages are okay except for +5V.

Checked AC voltage at 3J1 pin 10 and voltage is at 10.2V when it should be at 12V. So am I to assume that this is the root of my low 5V voltage issues and that the transformer needs to be replaced?

Just in case anyone needs to know my +5V DC at 3J5 pin 6 and 3J6 pins 7-9 reads anywhere from 2 VDC-3.2 VDC.
 
that sounds like a transformer issue to me, check the voltages on the lugs of the transformer

I'm thinking it's a transformer issue as well.

Anyone know if a System 3-6 power transformer is the same as what's used in System 9-11 games?

Anyone ever try running the 12VDC and 5VDC off of a switching PSU?
 
I've almost never seen a transformed go bad though, and the few times I have they always go totally dead on the output.

What are the input and output voltages at BR1? Remember, it's AC input and DC output.

-Hans
 
I've almost never seen a transformed go bad though, and the few times I have they always go totally dead on the output.

What are the input and output voltages at BR1? Remember, it's AC input and DC output.

-Hans

BR1 outputs are at +14VDC and -14VDC I can't recall the AC input but can check when I get home. I replaced 2N6057 with NTE 247 and IC1 with NTE 923D.
 
I have a Cyclone manual out....so that's what I'm looking at for schematics. If you read pin 10 from ground you only read half the wave (as mentioned, this is AC)....thus, only half the voltage. My manual actually lists 19.4VAC....10V center tap (which is what you're reading...it's center tap). Your voltage is fine. Do you have 12-15VDC at TP3, or across the big cap (C10). I'm suspecting a bum Q5.

Edward
 
BR1 outputs are at +14VDC and -14VDC I can't recall the AC input but can check when I get home. I replaced 2N6057 with NTE 247 and IC1 with NTE 923D.

If you're gettting 14v at the rectifier, than your transformer is working fine. AC inputs should be 14v AC if you're getting 14VDC output.

-Hans
 
I have a Cyclone manual out....so that's what I'm looking at for schematics. If you read pin 10 from ground you only read half the wave (as mentioned, this is AC)....thus, only half the voltage. My manual actually lists 19.4VAC....10V center tap (which is what you're reading...it's center tap). Your voltage is fine. Do you have 12-15VDC at TP3, or across the big cap (C10). I'm suspecting a bum Q5.

Edward

I'll have to check my manual to see what I get at TP3. Am I supposed to get 12VDC-15VDC across C10?


Is Q5 the +5 voltage regulator? That was my first guess as well but he said he replaced it.


Yep, twice in case the first one was bad. I used NTE 247 which came up as a replacement for the 2N6057. Replaced BR1 as well as IC1. I can't figure it out. It appears that the voltage is dropping somewhere. I guess I should replace the resistors and diodes that weren't previously replaced next.
 
I'll have to check my manual to see what I get at TP3. Am I supposed to get 12VDC-15VDC across C10?

TP3 is the same point as the positive side of C10....the negative side of C10 is ground. Yes, 12-15 volts.

Edward
 
Started going through the resistors before replacing them and all of them were spot on. Checked diodes and all of them were testing good again until I got to D2 and D5. D2 tested open and D5 gave me 500+ on both sides. Both are 1N4001, replaced them and all voltages are good. :D
 
Job well done!

Thanks, fired the bot up and just about everything works. I have a few coils that aren't working but will get those taken care of in short order. Ball eject, ramp and outholes are out. Jet bumpers, slingshots and others work fine. :)

Thanks for everyone's help so far, you guys are a great asset and I appreciate all of the help.
 
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