Electric components problems

Gachan

Hello,
I have two issues I want to bring to you, experts and amateurs alike:
1) I found 3 9v battery cases with leakage in a bulk I bought. I disassembled them (taking away the plastic compartment and removing the metal parts) and used the usual recipe of acid+toothbrush+drying. I could remove all solid leakage but could only save one case (which now works!). The other two's metal parts still look blackened or darkened by the leakage. They are not perfectly smooth to the touch although no solid materials remain on their surface. Also the circuits directly attached to the case have also suffered and I tried to treat them the best I could, but given you can't remove them I suspect some deposits might still lurk beneath them.
Any idea why it will not work? It's been cleaned, cloth then air dried, all components put back in their right places, all contacts seem ok...
2) There was also a monorail motor in the bulk. It looks fine but it doesn't work at all... I can't find a way to open the thing and peak inside to try and fix it...
Anyone know how to pull up such a stunt? I know these motors are tough and I never came upon a broken one so I'm quite helpless...
Thanks :)

oldtodd33

Pictures help if you can.

suprajames

I have a similar problem with a #7897-1 I found in a bulk buy, both the RC remote and train battery pack had suffered from leaked old batteries. I dis as you did and cleaned it all up as much as possible, any contacts were cleaned with a very low grit emery cloth to remove any built up corrosion and still no joy. The RC remote and the train receiver both have printed circuit boards which had been ruined, was hoping it was just the remote, but today the new remote i bought from Bricklink turned up and have found the train base/battery pack and receiver is also ruined. So now need to order a new one at around £20, so my advice would be replace any parts, but do it one at a time in case some bits are still working ok. I have tested the train motor and know it works so one less bit I have to buy.