Original 68000 - 90% working - Fixed?

[BlueBMW]

Hello all!  One of my systems, an Original 68000 has me stumped...

The system worked perfectly, loaded games no problem, sound was good, graphics output was good.  All was well.  Then one day, it wouldnt even power on.  No red light, nothing,   PSU totally dead.  So I installed a replacement PSU, and also replaced the battery on the mainboard while I had the unit apart.  

I Put it all back together after the power supply replacement and now the system powers on but locks up when it tries to load from drive 1.  It will load single disk games like Salamander or Cho Ren Sha with no trouble at all.  But any two disk games, it freezes up when it accesses drive 1.  I've run switch.x to make sure the system is set to 2mb ram (it has a 1mb internal expansion)  so its not an issue of running out of ram.  I've swapped every part out except the large mainboard and got the same results.  Different drives, different floppy cables, even another original working power supply.  When the system hangs, even pressing interrupt doesnt do anything.  Sometimes I'll get a cut off warning message on the display saying something about "Media"  I can hit "R" and keep retrying, but it doesnt successfully load from drive 1.  A few times while I had the system apart it worked loading a two disk game, but after reassembling, its no go.

Any suggestions are welcome!  If you need pics or video of what its doing, i'll take some.

[caius]

Hello all!  One of my systems, an Original 68000 has me stumped...

The system worked perfectly, loaded games no problem, sound was good, graphics output was good.  All was well.  Then one day, it wouldnt even power on.  No red light, nothing,   PSU totally dead.  So I installed a replacement PSU, and also replaced the battery on the mainboard while I had the unit apart.  

I Put it all back together after the power supply replacement and now the system powers on but locks up when it tries to load from drive 1.  It will load single disk games like Salamander or Cho Ren Sha with no trouble at all.  But any two disk games, it freezes up when it accesses drive 1.  I've run switch.x to make sure the system is set to 2mb ram (it has a 1mb internal expansion)  so its not an issue of running out of ram.  I've swapped every part out except the large mainboard and got the same results.  Different drives, different floppy cables, even another original working power supply.  When the system hangs, even pressing interrupt doesnt do anything.  Sometimes I'll get a cut off warning message on the display saying something about "Media"  I can hit "R" and keep retrying, but it doesnt successfully load from drive 1.  A few times while I had the system apart it worked loading a two disk game, but after reassembling, its no go.

Any suggestions are welcome!  If you need pics or video of what its doing, i'll take some.

I could recommend you to check the FDD ribbon cables since you said you have tried other drives without success.Let us know.

P.S.
If you can, post the warning message here.

[BlueBMW]

I've tried different floppy cables, and basically here's what I've narrowed it down to....

When the drives are fully installed and screwed into the case, I get the problem.  If I leave the drives loose and hanging out of the system, they work fine.  I'm investigating if somehow there is some flex or something happening when they're installed that is causing the problem.

Update:

This is very strange....  There is a small bracket that fits between the power supply and the floppy drive housing.  It really serves no function other than to maybe add some rigidity and maybe link grounds somehow.  With it installed, I have problems.  Without it, no trouble at all.  I wonder if with the swapped power supply, somehow the ground paths have been altered from the original design.  Just doesnt make any sense at all.

I tested for ac or dc current between the power supply housing and the floppy drive housing just t be sure there isnt something funny going on.  Nothing at all.  Seems very strange.

Here's some pics of the offending component, though I'm still confused as to how one small bracket could make such a difference.  I did try installing it both in front and behind the floppy drive to see if maybe it was a clearance / mounting position issue.  Didnt make a difference.