OIB1981
Member
My Earthshaker was running decent when I had it out in the garage. Everything ran only problem I had was speech wasn't working in the sound department. So I decide to take the machine apart so it would be easier to move downstairs. My biggest fear was I'd remove the head and something get messed up in the wiring area. Seems my biggest fear came true. I also removed the playfield for cleaning reasons.
Anyhow I was pretty careful to get all the connections back in the right spot. While removing I put a zip tie around the connections and taped a label to zip tie that said the general area where the connections went. Even took pictures to compare before booting.
When I powered on ES last night the CPU board show +5 solid then the Diagonstic and blanking would stay on for few seconds then just go out. So I guess it isn't passing the power on test. The score board wouldn't display anything but a solid diagonal line all the way to the lower left corner.
Anyhow there only two things I did to the boards while the machine was apart. I did some connection repair on the interconnect board and I replaced the BR1 rectifier and Q4 Transistor on the power supply board. I'm pretty confident it wasn't the interconnect repair that could cause an issue. So I checked my power supply board TP points and here what I got.
TP1 +5.08
TP2 0.07
TP3 +12.25
TP4 -14.34
Those reading seemed pretty much right on cept for the TP4 which shold be -12 volts. I reaplaced the Bridge with GBPC3504W Found at http://www.greatplainselectronics.com and the Q4 Tansistor with 2N6059 found at the same site. Do these appear to be the correct replacements? Only thing was they were higher in the voltage. Didn't think that would be an issue.
I've removed all connectors to the CPU and cept J17 and the Blanking and Diagonstic light still go out.
Any body have any suggestions on what to do? I thought about switching the transistor back with the old one. After that other then checking all the connections again I'm kinda lost.
Anyhow I was pretty careful to get all the connections back in the right spot. While removing I put a zip tie around the connections and taped a label to zip tie that said the general area where the connections went. Even took pictures to compare before booting.
When I powered on ES last night the CPU board show +5 solid then the Diagonstic and blanking would stay on for few seconds then just go out. So I guess it isn't passing the power on test. The score board wouldn't display anything but a solid diagonal line all the way to the lower left corner.
Anyhow there only two things I did to the boards while the machine was apart. I did some connection repair on the interconnect board and I replaced the BR1 rectifier and Q4 Transistor on the power supply board. I'm pretty confident it wasn't the interconnect repair that could cause an issue. So I checked my power supply board TP points and here what I got.
TP1 +5.08
TP2 0.07
TP3 +12.25
TP4 -14.34
Those reading seemed pretty much right on cept for the TP4 which shold be -12 volts. I reaplaced the Bridge with GBPC3504W Found at http://www.greatplainselectronics.com and the Q4 Tansistor with 2N6059 found at the same site. Do these appear to be the correct replacements? Only thing was they were higher in the voltage. Didn't think that would be an issue.
I've removed all connectors to the CPU and cept J17 and the Blanking and Diagonstic light still go out.
Any body have any suggestions on what to do? I thought about switching the transistor back with the old one. After that other then checking all the connections again I'm kinda lost.