bilbomacuser
Active member
I got my LCII out of the loft after many years and found the following:
Power supply ticked --> Replaced the 4 ELNA capacitors
Fan powered on but didn't boot or make a sound -- Replaced all SMD capacitors (damaged a pad for the 6.3V capacitor, so replaced that with a radial)
Fan powered on initially, but then made cyclic movements and speaker made sound in time with this, still didn't boot or make a sound --> Removed and reseated one of the EPROM chips
Fan working normally, and could hear hard drive running, no chime no boot --> Reseated other EPROM chips
No change from above, removed RAM and VRAM --> chimed and booted, no video --> Cleaned terminals on VRAM and reseated
Chimed, and booted, all seemed to work fine --> cleaned terminals on RAM and reseated
Chimed, booted and worked fine
24 hours later...
Turned on, no chime, no boot, fan running -->tried various things like reseating VRAM etc, none that made a difference
After a while chimed and booted, but keyboard and mouse not working --Rebooted several times (by turning off/on), checked voltage to ADB port etc
After a while keyboard and mouse working ok (and whole system is working fine) --> Checked voltage of power supply while running, one is 5.1V, one is 11.8V, one is 5.0V.
My next plan is to replace the other electrolytic capacitors in the power supply.
My questions are:
Should I replace the large 180uF 385WV (and if so, with what?)
Could the 11.8V be part of the problem?
Could it be that the power supply is 'warming up' (due to remaining old capacitors) hence why things like removing VRAM 'appeared' to cause it to start working?
Could the tantalum capacitors need replacing?
Not knowing much about capacitors, and with Mouser having many different variations, how can I be sure to get the best type? I'm replacing like for like in terms of electrolytic/SMD/radial, capacitance and voltage (and then choosing the highest temp and longest life it other factors are the same), but have no idea whether I'm getting the other things right (ripple current, resistance etc).
Power supply ticked --> Replaced the 4 ELNA capacitors
Fan powered on but didn't boot or make a sound -- Replaced all SMD capacitors (damaged a pad for the 6.3V capacitor, so replaced that with a radial)
Fan powered on initially, but then made cyclic movements and speaker made sound in time with this, still didn't boot or make a sound --> Removed and reseated one of the EPROM chips
Fan working normally, and could hear hard drive running, no chime no boot --> Reseated other EPROM chips
No change from above, removed RAM and VRAM --> chimed and booted, no video --> Cleaned terminals on VRAM and reseated
Chimed, and booted, all seemed to work fine --> cleaned terminals on RAM and reseated
Chimed, booted and worked fine
24 hours later...
Turned on, no chime, no boot, fan running -->tried various things like reseating VRAM etc, none that made a difference
After a while chimed and booted, but keyboard and mouse not working --Rebooted several times (by turning off/on), checked voltage to ADB port etc
After a while keyboard and mouse working ok (and whole system is working fine) --> Checked voltage of power supply while running, one is 5.1V, one is 11.8V, one is 5.0V.
My next plan is to replace the other electrolytic capacitors in the power supply.
My questions are:
Should I replace the large 180uF 385WV (and if so, with what?)
Could the 11.8V be part of the problem?
Could it be that the power supply is 'warming up' (due to remaining old capacitors) hence why things like removing VRAM 'appeared' to cause it to start working?
Could the tantalum capacitors need replacing?
Not knowing much about capacitors, and with Mouser having many different variations, how can I be sure to get the best type? I'm replacing like for like in terms of electrolytic/SMD/radial, capacitance and voltage (and then choosing the highest temp and longest life it other factors are the same), but have no idea whether I'm getting the other things right (ripple current, resistance etc).
