68kMLA Classic Interface
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| Click here to select a new forum. | | Macintosh Plus Logic board problem | Posted by: andy2k68kMLA on 2016-09-01 13:39:02
Hello everyone
I'm trying to troubleshoot a 1MB logic board (820-0174-C). It doesn't chime only does what I posted in the video. I tried reseating ram, booting only with 1 stick of RAM, etc. reseating and cleaning hi and lo ROM DIPS. Voltages are good from a good, working analog board. The -5 voltage regulator on the logic board measures okay (-4.999 volts). I hear the TSM DIP can go bad too. Any other ideas as to what might be wrong? Any other guides for troubleshooting the logic board. Please watch attached video. Thanks everyone.
trim.524A3B4F-052B-44CA-9011-5E24ED3DEFEC.MOV
| Posted by: unity on 2016-09-01 13:47:09
I did not watch vid, but FYI you can not boot with one stick of RAM. Must be installed in pairs and configured as such.
| Posted by: andy2k68kMLA on 2016-09-01 13:51:27
Okay thanks for the info. I tried with two matching sticks installed too same result as having all 4 installed
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