I'm working on a recently repopulated Lost World pf. Yesterday, everything booted up, and aside from some GI lights and one coil, was all working. There were multiple frayed spots/breaks in the GI ground wiring, which I mostly corrected. Almost everything lights properly now, but the game now won't boot with everything connected. Boots fine with J4 only, J4 + J1, and J4 +J1 and J3. So, the problem is isolated to J2 and the playfield. I think pretty obviously I connected something incorrectly and created a short. Any tips on how I narrow it down?

Thanks!!

#2 3 years ago

AMS

barakandl

nvram.weebly.com

12y 132K 10,420

OP
Quoted from bobnatlanta:
I'm working on a recently repopulated Lost World pf. Yesterday, everything booted up, and aside from some GI lights and one coil, was all working. There were multiple frayed spots/breaks in the GI ground wiring, which I mostly corrected. Almost everything lights properly now, but the game now won't boot with everything connected. Boots fine with J4 only, J4 + J1, and J4 +J1 and J3. So, the problem is isolated to J2 and the playfield. I think pretty obviously I connected something incorrectly and created a short. Any tips on how I narrow it down?
Thanks!!

measure voltage on each wire going to j2 and/or check continuity to 43v, 6vac. 6vdc supplies

#3 3 years ago

AMR

BigAl56

Pinside+ Frequent

Palatine, IL

7y 64,800 1,659

You have it diagnosed pretty well. Probably a short with one of the wires. If you cant find it pull the wires from the connector and place them back one at a time until the came stops booting. Then you'll have it narrowed down to a specific wire to check.

#4 3 years ago

RWK

bobnatlanta

Pinside member

Atlanta, GA

19y 65,150 623 3 9

Yes....memory banks warming up. I've done this procedure before. Thanks Big Al.

barakandI - you've mistaken me for someone with waaaaay more tech knowledge then I actually have. I am at the red lead goes here, black lead goes here level.

#5 3 years ago

AMS

barakandl

nvram.weebly.com

12y 132K 10,420

OP
Quoted from bobnatlanta:
Yes....memory banks warming up. I've done this procedure before. Thanks Big Al.
barakandI - you've mistaken me for someone with waaaaay more tech knowledge then I actually have. I am at the red lead goes here, black lead goes here level.

If J2 stops the MPU from booting likely a swtich is wired to or touching a supply voltage or ground under the playfield. Feature lamps are 6vdc. GI lamps are 6.3vac. Solenoids are 43v. One side of the GI braid is ground. With a meter you can measure voltage on each wire in J2. Black lead on ground red lead check volts dc of each wire one at a time in J2. Then check do the same thing and check volts ac. With the power off and DMM on continuity test or resistance and check each wire in J2 to see if it is shorted to earth ground. One lead on ground other lead check each wire.

When a switch matrix is shorted under the playfield the MPU power on self test may detect that it can't control the PIA chip and you get the non boot (no 4th flash).

#6 3 years ago

RWK

bobnatlanta

Pinside member

Atlanta, GA

19y 65,150 623 3 9

Found it. The 'bad' wire wire was at pin 5 on J2, a yellow/red wire. Traced it and found a solder splash had shorted a lamp to a switch. Now the game boots reliably. Many thanks!! Only a couple more issues and she's ready to play.

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