Thinkpads Forum

I had mentioned that the 600E which I have been working on had a power connector problem. Assaulted that last night with a meter and a soldering iron. My hypothesis that the solder traces were cracked at the board was wrong: they were solid. There was metallic gummy swarf in the area which I thought was allowing the hot to short to ground. Cleaned that away, reassembled, rebooted, and power seems reliable now!

However, the machine didn't boot at first despite having power (verified by the meter across the fuse). A couple of cycles of the switch and it came up. But this morning it's in an unbootable coma.

Turning the power on produces the following:

(a) all LEDs light briefly for selftest, as expected, including the power LED;

(b) there should be a beep, but the speaker cable is torn, so I do not know whether it's doing that or not;

(c) there is no familiar screen flicker;

(d) the POST memory inventory and Thinkpad logo do not appear;

(e) the LEDs go out except for the drive access LED and the LED on the right of the linear array (whose function escapes me, but I think it is normal for it to be lit);

(f) the fan runs.

That's it. The machine remains in that state (the two LEDs lit and the fan running) with no change. The disk doesn't seem to be actuallyt accessed.

I had removed the CPU daughtercard and fan in order to get access to the power connector area, then replaced it. I am thinking that this was probably a bad idea, and that I have either mucked up the MMC2 connector or have static-sparked the processor.

It just occurred to me as I wrote the foregoing that I had not done a test of booting with the daughtercard removed. Just did that, and the symptoms are identical.

I'm annoyed with myself over this, because I noticed while reinserting the daughtercard that there is a tab on the Ultraslimbay frame which serves no apparent function other than to impede the linear movement of the daughtercard into the motherboard connector. I was perhaps overconfident in my abilities, and instead of removing the frame I had simply moved the d/c laterally to get around it. That may have left the connector misaligned when I pressed it back into place.

I have examined the pins and sockets visually and I do not see any gross deformations of pins nor any missing metal. But the electrons aren't flowing to where they need to go.

Anyone have any input on this situation? Thanks!

Get a new CMOS battery and try it again.

Regards,

James

JHEM wrote:Get a new CMOS battery and try it again.

Sensible idea. Done.

Has had no effect on the overall situation.

I tore the system down to the bare motherboard again and did a slow careful reassembly, to ensure that I had not missed any connectors or grounds. It all seems okay.

I grabbed a seven-power optical magnifier headset to check the CPU daughtercard connector. I found one very slightly twisted pin on the daughtercard side. Realigned it with a precision tweezer.

On the motherboard side, the individual socket holes each have a pair of tabs which are obviously intended to grab the incoming pin under tension. One tab in one pair was a bit misaligned -- not the one which matches the bent pin in the d/c!

I went to straighten that tab and promptly broke off the very top of it. Grrrrrrr. But another few minutes had me convinced that what is left should still make a reasonably solid electrical connection.

Not sure if I have made a bad situation worse or not. I think the next step is to try to find a known good MMC-2 daughtercard and see if this motherboard will boot with that installed.

Take your optical headset and examine the area under the MMC socket on the MB. I've seen people accidentally break some traces when installing the module into the socket.

After that, I'm stumped and would follow your thought to change the module or MB.

Regards,

James

About a week ago I bought a 600x off of Ebay with the EXACT same symptoms,including the HDD LED staying on during power up... I took out the 650mhz CPU and replaced it with a 366PII from an old 600e I had laying around,and it worked.. So feeling confident I ordered a 750mhz,got it and tried it...Nothing,zip...

Took that out and put in a 600mhz I had in the 600e(swapped out that 366) and the 600mhz worked..

So I too am confused.. I have a 650,and a 750 that don't work in the machine,but the 366 and 600 do..So is it the machine? The CPU's? I have done a lot of reading here and those MMC-2 CPU's seldom have problems,so I have to doubt that I got 2 bad MMc-2's..Any ideas??

right. I had the EXACT symptoms described above, just after id put in my 500mhz PIII into my 600e. I put back the 366, same problem. I then removed all the ram, the hard drive, anything in the ultrabayand card slots etc and flicked the power switch a few times (without the AC or battery connected)

put everything back and hey presto, i get the beep and the screen flickers! (and i nearly die of relief!:) )

I hope this works for you, it does sound like the identical problem to what i experianced. I think it works by removing any residual charge or memory effect in the rameemajig or something!