PSU 6128 disc drive problem

[ComSoft6128]

OK I've blown a few fuses in my head this morning over this so help would be appreciated.
Switched on the 6128 (powered by PSU's) and tried to CAT a disc and get "Drive A disc missing: Retry, Ignore, Cancel"
- Aargh!
Tried a few other discs same result.
Bring out the backup machine - same result.
Bring out the second backup machine - same result.

So three duff drives?
Unlikely.
More likely the 12v PSU is at fault.

So I'm looking now for the "Gold Standard" of 12v PSU's - can anyone recommend the best one?

[ComSoft6128]

This?

https://www.amazon.co.uk/Meanwell-original-GST60A12-P1J-Reliability-Industrial/dp/B06WLNWQYY

[roy bates]

personally id probably get a duel rail supply
something that has 5 and 12 volts with decent protection

[ComSoft6128]

OK,

But would that one do the job?

[roy bates]

probably if your using two supplies for your 6128 and you suspect the 12 volt side is gone

if you had a multimeter,i suppose you could check if its faulty

[ComSoft6128]

No multimeter but when I removed it from the rats nest of cables under my desk I noticed the LED wasn't lit.

[roy bates]

yeah,probably more than likly dead,unless the fuse blew in the plug or the unit

[ComSoft6128]

Looking at another cheaper one I see this:

"The centre of the power plug is positive, the outer, negative." - is that suitable for the CPC?

[roy bates]

actaully it doesnt say what the polarity of the plug is,which is important

which on the 6128 is center ground and barrel is 12v and its a socket not a plug for the cpc drive

Looking at another cheaper one I see this:

"The centre of the power plug is positive, the outer, negative." - is that suitable for the CPC?

[GUNHED]

Attention!!! The plus and minus poles of the 12 Volt connector of the CPC are exchanged.
There is (somewhere) a Wiki page about that.

When I bought a 12 Volt supply I cut the cable and soldered both lines together vice versa.


However, even without 12 Volt you can use a 3,5" drive a port B (they only need 5 Volt), just to check if anything else is working. 

[roy bates]

actually an adaptor could be made for standard center pin positive 12 volt supplies,to adapt it

but,this may be beyond you with no tools

[eto]

Here are all the specs: 

https://www.cpcwiki.eu/index.php/Power_Supply_for_CPC_and_CPC_plus

As already mentioned, please remember that 12V is center ground!


I have used several power supplies for the 12V and never had any issues. I even "stole" the 12V from a LCD TV and it was totally fine, while using a 5V supply for the computer. 

A combined 5V/12V supply would e.g. be the Meanwell 35W RD35A. But it needs a custom case.

Every now and then you can find a PSU with 5V and 12V on Ebay, e.g. for some Laptop models, but of course also requires some soldering then. Just don't get the cheap ones for external drives. They most likely will not reliably deliver >2A on 5V.

[ComSoft6128]

Thanks Roy!

The PSU you recommended arrived this afternoon and the 6128 is working fine

[vasilisk]

Thanks Roy!

The PSU you recommended arrived this afternoon and the 6128 is working fine

care to share which one you bought? 

[ComSoft6128]

Sure, this one:

https://www.amazon.co.uk/Supply-Adapter-100V-240V-Switching-Camera/dp/B07S7PH77C

[ComSoft6128]

What seems odd to me is how the failure was gradual and initially mimicked (to me) dodgy discs.
Some discs worked some didn't.
I know very little about electronics so expected a PSU problem to be immediate and final.

[Bryce]

PSU's that are having problems keeping the voltage or current stable can cause many weird and wonderful effects.

Bryce.

[roy bates]

very true bryce,it doesnt have to drop by much at all,probably around 11-10.5 volts or there abouts

some pc supplies die that way as well,more noticably under load