PowerBook switches off after repair

[MikeatOSX]

Next problem with a PowerBook 5300ce. 
I bought this PB 5 years ago but it had a leaking battery and did not boot. On the right side of the power supply board the connectors for the main battery were light blue, corroded and broke when I tried to clean them. 
I cut off the leaking battery and used the empty cover to close the bay. 
I also bought a new PRAM battery.
From this time on the PB 5300ce worked like a charm. 
With one exception: the insecure power supply connector. 
Today I desoldered and soldered again this connector and I tested my soldering with the PowerBook still open. With extra memory and mouse but without PRAM battery, trackpad and keyboard connected. What should I say: the PB started after a reset and worked perfectly. 
So I connected PRAM battery, trackpad and keyboard and closed the PB. 
But now, when the PB boots, the welcome screen appears but then the PB shuts off each time. 
I suppose it's something wrong with trackpad or keyboard connector or PRAM battery. 
What do you think. Any suggestions, please?

BTW: can I use the power supply card of a 5300 cs to replace the corroded one of my 5300 ce ?

 

[MikeatOSX]

I found the reason of the "switch-off" myself after hours. 

The solution was: I heard a warning sound.

The Powerbook did not shut down, but it continued booting with totally dimmed screen. I have a compact flash card inside so it's a very silent PowerBook. 

So I saw a problem, where there was no problem. After hours with the power supply it always boots normal now. 

 

[MikeatOSX]

I had new problems again: got GLOD and couldn't start again for days. 
So I tried to find the failure again:
it was the trackpad. When I removed it, the 5300ce booted immediately. And still does always. I'll try a second trackpad (I bought 5 PB 5300 some years ago).
Interesting new "feature": After switching on I get a flickering screen for several seconds, but when the PB begins to load the system (with or without extensions), flickering stops and I get a normal screen until next booting. 
Can anybody imagine the reason for this flickering?

 

[MikeatOSX]

My second 5300ce also doesn't start with it's trackpad connected. 

I think I have to clean all contacts...