Twin Famicom Disk Bios Not Loading

[Michellybells]

I have a Twin Famicom system that I'm having a problem with. The cartridge sections of the system work fine, however when you flip the switch to Disk mode, you just get a blank screen. I don't currently have a voltmeter to check the caps and things, but none of them seem damaged or leaking. My plan is to swap the 23CC chip from a spare RAM Adapter, but they same to be a slightly different chip revision. The RAM Adapter is 01A while the Twin is 02. Then again, I don't even know which chip stores the FDS bios to begin with, I'm just assuming it's on the 23CC. Any advice?

[P]

I think a damaged ROM chip is probably a very rare problem. Is there nothing else you can rule out before you start replacing chips? I think electrolytic capacitors may often fail without showing any signs of leakage or anything, so I would try to replace those for brand new ones first.

[Sydsydsyd]

Well I am with the same problem.

Some time ago I closed the pins of the socket because it was very loose and I think that the pins that are facing each other were short-circuiting when there is no cassette placed in the socket.

I think this may have burned a chip on the floppy side of the motherboard. If that were the case, which part of the PCB (which chips) should I check? Is there some kind of fuse or logic gate that could blow due to what you mention? Thank you very much.

I hope this will help us to solve this problem, I searched a lot on the internet and couldn't find anyone mentioning that this could be the cause of this grey screen issue on disk mode.