terminalcancerman
New member
Greetings all.
I've performed a recap of a Mac SE with a Sony PSU to include the analog board and logic board. When first applying power it powered up without issue and I shut it down. When applying power for the second time, I heard a snap from the PSU but the machine stayed powered up. I was able to adjust the screen dimensions and shut it back down. I opened up the PSU and saw that the fuse was blown. I removed the board from it's enclosure and found a trace (D151 - to TH151) had burned up. I replaced the fuse and tested for a short of the PSU without bodging the burned trace and it tested good on all rails. The analog board also shows no shorted rails. The Logic Board similarly showed no shorts. Is it possible that the Inrush Current Limiter (TH151) has failed? I tested its resistance in-circuit and it read sub-ohm while rated at 8 ohm.
I've got a few Sony's and an couple of Astec supplies I can toss in there but I'd prefer finding the fault before firing the parts cannon. I find it hard to believe that this component chose now to fail, but I did get that first cold boot without issue.
Another question: If the ICL has indeed failed, is replacing it in kind the proper route, or should I replace it with a higher rated component? It's presently 8 ohm 4 Amp.
Another point of fact is that I replaced the Miniscribe HDD with a BlueSCSI V2 powered by the SCSI bus. Could that be a problem? I've overloaded supplies before by not having a HDD connected, but I've never smoked a trace.
Thanks so much!
I've performed a recap of a Mac SE with a Sony PSU to include the analog board and logic board. When first applying power it powered up without issue and I shut it down. When applying power for the second time, I heard a snap from the PSU but the machine stayed powered up. I was able to adjust the screen dimensions and shut it back down. I opened up the PSU and saw that the fuse was blown. I removed the board from it's enclosure and found a trace (D151 - to TH151) had burned up. I replaced the fuse and tested for a short of the PSU without bodging the burned trace and it tested good on all rails. The analog board also shows no shorted rails. The Logic Board similarly showed no shorts. Is it possible that the Inrush Current Limiter (TH151) has failed? I tested its resistance in-circuit and it read sub-ohm while rated at 8 ohm.
I've got a few Sony's and an couple of Astec supplies I can toss in there but I'd prefer finding the fault before firing the parts cannon. I find it hard to believe that this component chose now to fail, but I did get that first cold boot without issue.
Another question: If the ICL has indeed failed, is replacing it in kind the proper route, or should I replace it with a higher rated component? It's presently 8 ohm 4 Amp.
Another point of fact is that I replaced the Miniscribe HDD with a BlueSCSI V2 powered by the SCSI bus. Could that be a problem? I've overloaded supplies before by not having a HDD connected, but I've never smoked a trace.
Thanks so much!