CPC6128 - power problems

[dave]

Hello.


I've just acquired a CPC6128 which apparently wouldn't load anything from the floppy drive (not sure of the exact context of that).


I've had it apart this morning, replaced the belt and given it a general service.  I also noticed somebody had been in there before and had damaged two wires - the power cable to the floppy drive, and the earth cable (which had been "repaired" in the most horrendous way imaginable).  Both had been trapped in the case and the earth had been screwed completely through.  I've re-soldered both, and checked with a multimeter - all have continuity.


I'm using a TV and the MP-2 that came with it as I don't have a 6128 monitor.  If I switch it on with the 5v supply only connected, everything's fine (except the drive won't work as it runs from the 12v rail of the MP-2).  If I switch it on with both the 5v and the 12v connected, it's a different story - it won't even switch on.  I'm assuming that the MP-2 has some sort of overload protection, as it then won't switch on again until I've disconnected the mains supply.


If I switch on with only the 5v line connected, then connect the 12v supply AFTER I've switched it on, everything still works.  But upon trying to load something from the floppy drive (and there consequently being a 12v draw), the MP-2 promptly trips off.


What's you technical folks' thoughts on this?  Is the fault more likely with the floppy drive, or the MP-2?  Is there anything I can do to test/eliminate?


Thanks!


(PS: Pic attached - somebody actually thought this was an acceptable repair!)

[Bryce]

Any chance that the previous owner had a 3.5in drive or HxC installed and has swapped the pinout on the floppy power cable?
The red and yellow cables should be in the opposite positions to a normal PC drive.

Bryce.

[dave]

I'm not sure - I've little experience of that sort of thing.  It looks pretty standard, right?

[chinnyhill10]

(PS: Pic attached - somebody actually thought this was an acceptable repair!)

That's an odd place for the wire to break. I wonder what the previous owner had been up to.

[dave]

the break was exactly in line with the screw hole - seems like they've trapped the cable when putting it back together (presumably the had it apart to try to fix the drive - and the inside of the case was super-clean - barely any dust at all for a 28 year old computer), and pushed the screw in right through it.

[kevin.c]

I just looked inside my cpc. The red wire is close to stepper motor, so in your cpc connector is not reversed for sure.
About MP-2. I think problem must be with old electrolytic capacitors and MP-2's power supply has no enough currant capacity. The disc's motor needs some more  power at start.