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General Category => Technical support - Hardware related => Topic started by: ComSoft6128 on 09:00, 17 June 22

Title: PSU 6128 disc drive problem
Post by: ComSoft6128 on 09:00, 17 June 22
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?
Title: Re: PSU 6128 disc drive problem
Post by: ComSoft6128 on 10:59, 17 June 22
This?

https://www.amazon.co.uk/Meanwell-original-GST60A12-P1J-Reliability-Industrial/dp/B06WLNWQYY
Title: Re: PSU 6128 disc drive problem
Post by: roy bates on 14:11, 17 June 22
personally id probably get a duel rail supply
something that has 5 and 12 volts with decent protection
Title: Re: PSU 6128 disc drive problem
Post by: ComSoft6128 on 14:12, 17 June 22
OK,

But would that one do the job?
Title: Re: PSU 6128 disc drive problem
Post by: roy bates on 14:16, 17 June 22
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
Title: Re: PSU 6128 disc drive problem
Post by: ComSoft6128 on 14:18, 17 June 22
No multimeter but when I removed it from the rats nest of cables under my desk I noticed the LED wasn't lit.
Title: Re: PSU 6128 disc drive problem
Post by: roy bates on 14:21, 17 June 22
yeah,probably more than likly dead,unless the fuse blew in the plug or the unit
Title: Re: PSU 6128 disc drive problem
Post by: ComSoft6128 on 14:30, 17 June 22
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?
Title: Re: PSU 6128 disc drive problem
Post by: roy bates on 14:31, 17 June 22
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
Quote from: ComSoft6128 on 14:30, 17 June 22Looking at another cheaper one I see this:

"The centre of the power plug is positive, the outer, negative." - is that suitable for the CPC?
Title: Re: PSU 6128 disc drive problem
Post by: GUNHED on 14:46, 17 June 22
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.  :)
Title: Re: PSU 6128 disc drive problem
Post by: roy bates on 14:49, 17 June 22
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
Title: Re: PSU 6128 disc drive problem
Post by: eto on 21:03, 17 June 22
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.
Title: Re: PSU 6128 disc drive problem
Post by: ComSoft6128 on 14:27, 18 June 22
Thanks Roy!

The PSU you recommended arrived this afternoon and the 6128 is working fine :)
Title: Re: PSU 6128 disc drive problem
Post by: vasilisk on 19:26, 19 June 22
Quote from: ComSoft6128 on 14:27, 18 June 22Thanks Roy!

The PSU you recommended arrived this afternoon and the 6128 is working fine :)
care to share which one you bought?  8)
Title: Re: PSU 6128 disc drive problem
Post by: ComSoft6128 on 05:31, 20 June 22
Sure, this one:

https://www.amazon.co.uk/Supply-Adapter-100V-240V-Switching-Camera/dp/B07S7PH77C
Title: Re: PSU 6128 disc drive problem
Post by: ComSoft6128 on 05:37, 20 June 22
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.
Title: Re: PSU 6128 disc drive problem
Post by: Bryce on 13:22, 20 June 22
PSU's that are having problems keeping the voltage or current stable can cause many weird and wonderful effects.

Bryce.
Title: Re: PSU 6128 disc drive problem
Post by: roy bates on 17:48, 24 June 22
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
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