I have a 6128 and am using it with the RGB SCART connector and 5v supply. Works fine and the disk drive works fine , there is nothing feeding the 12V power supply. I did get a 12V psu thinking i needed it, but in fact it makes things worse!
Whats going on here?! without the 12v supply it works fine, with the 12v supply it wont read discs , keeps disc searching or resets quickly.
Are you plugging the 12v into the 5v power connector? That’s a good way to quickly fry your 6128.
Can you share a picture of your 6128 setup?
The 12v plug goes into the CPC monitor.
If you’re using an external PSU, have you checked that it’s the right polarity?
On the CPC I think (please correct me if I’m wrong) that the 12v and the 5v have opposite polarities.
yes its a correct PSU for the 12V (bought the other day)
So it seems strange that it works with just the 5V supply connected 
The computer itself and the disk drive circuits should work with 5v only, the 12v is for the disk drive motor as far as I know.
Do you have another disk drive at hand to test? Maybe the motor on the one you’re testing is either broken or needs some love.
Moved to the correct category
The original disk drive won’t properly work with 5V only. My first guess: It’s either a replacement drive (maybe from a Plus 6128) or someone added a 5V/12V converter inside the CPC.
We can help if you add a picture of the drive and the insides of the CPC.
I think it has to be the disks thats the issue. Just unlucky that three disk games i tested had issues. I put the disk drive in a different machine and same issue. Then fired up Red Arrows on disk and worked perfectly (without the 12V connected).
Run diagnostics on my machine and no problems with ROM or memory.
The disk drive motor shows 5 Volt on the back of the motor
Can’t believe I never noticed that! This is the 6128 I have had since 1989 ,got it from my uncle and don’t think he would have changed anything.
Hi MagicKnight
what is the EME number on the Side of the drive - Just curious ??
Keep Safe.
Ray
Really interesting. Seems this is using a 5V motor which to my knowledge was only used on the Plus. We might need to update some pages
Can you please share a picture from the side of the drive with the exact model number?
here you go. One good thing is i can remove the 12V cable seeing as i dont need it any more or indeed ever did!
And this is a 3-wire cable to the drive, right? So the 12V are no longer fed into the drive at all…
The EME-157 is indeed a 5V only drive and until now it was not documented that it had also been used in some CPC 6128. I added it here now: Amstrad FDD part - CPCWiki
Yes it’s 3 wire.
I got a new copy of F-16 combat pilot and it loaded up fine, so it was the disk.
The marking on the case indicates it was built in 1988. That seems a bit early for 5V-only floppy drives, that’s not even a cost-down motherboard. But why go to the trouble of replacing the drive but leave the 12V cable in place? This is Amstrad: Every penny counts! Weird.
To not confuse the customer maybe?
It might also have been a replacement for a malfunctioning drive but then the cable would still be 4 wire.
But there seems to be some variation. I just acquired a German Amstrad (not Schneider) CPC 6128 and instead of the typical floppy cable with its red, green, grey wires it’s a standard grey flat cable with no wires separated. It also doesn’t look like a replacement.
