R50 Boot / POST Problem - Need suggestions/fix!

[underclocker]

I have an R50 that will only boot when using the battery - it will frequently boot with just the battery installed.

It runs fine once on.

The machine will stay on when I plug in the AC adapter after it boots with battery only. It recognizes when on AC power or off. The battery will charge normally whether on or off. The machine will reboot without a problem once it boots with battery only. It will reboot without an issue with the AC adapter attached or not.

With the AC adapter alone or with the battery installed with it, it won't boot or POST, no beeps, but power LED, battery LED (when installed) and fan go on.

I've tried many things to get it to work including;

-swapped sodimms
-tried different sodimm sockets
-removed wifi adapter
-removed CDC adapter
-removed ultrabay drive
-removed hard drive
-reseated CPU
-disconnected LCD cable
-tried with external display
-different keyboard
-different battery
-different AC adapter
-all IBM PC Doctor tests
-pressing the power button dozens of times
-holding the power button down for two minutes
-swapping the CMOS battery
-disconnecting the CMOS battery for 24 hours
-compressed air cleaning
-disconnected firewire port
-updated BIOS to most recent version
-updated EC to most recent version
-F9 in BIOS, then F10 to save, reboot
-swapped CPU

Any other ideas or is the planar (a.k.a. motherboard, systemboard) in need of replacement? (Out of warranty.)

Thank you.

[bontistic]

Just some quick thoughts:

1. Latest BIOS/EC?
2. Tried refreshing the CMOS in BIOS settings? (pressing F9 while in BIOS setup, I know removing the CMOS battery does the same trick but just in case)
3. What happens if you press ESC right after power up?
4. Power up, if no post, power down and repeat several times?

[underclocker]

Yes. I tried all four items, pressing ESC after power up does nothing. Multiple on/offs does nothing.

The power on seems normal at first, with keypress of ON switch, the fan turns on, the num lock, caps lock, power, battery and standby LEDs all illuminate for a split second, then the num lock and caps lock LEDs stay illuminated for another brief moment, then just the power LED stays illuminated (along with the fan being on).

Every time the same.

UPDATE on booting with battery. Now it appears to only boot from battery after a few hour rest. Doesn't look good.

[underclocker]

It needs a motherboard or motherboard repair. I'll part this one out, model 1836-3SU.

[vanaya]

I tried to DL the hmm for the r50, but kept getting errors. Will the fan fit on an R40??