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Power supply for QL

Posted: Mon Feb 25, 2019 10:11 am
by Jack_Free
Hello,

I'm looking for a QL-friendly power supply, including the end cap.
Alternatively, some idea of how to make this resource from the new components.
Thank you
Jack

Re: Power supply for QL

Posted: Mon Feb 25, 2019 3:40 pm
by drdivago
Hi Jack,

FYI I'm currently investigating into assembling two PSUs to power a QL, similar to an object which is currently on offer on eBay by a French guy https://www.ebay.co.uk/itm/Alimentation-secteur-power-supply-pack-pour-Sinclair-QL-Quantum-leap/283368071584?hash=item41fa0da1a0:g:8dcAAOSwrjVcWqip:rk:19:pf:0.

Ciao
Leo

Re: Power supply for QL

Posted: Mon Feb 25, 2019 4:40 pm
by Dave
That looks truly awful.

If you are comfortable soldering and identifying components, you can use a small PC power supply, remove the 12v regulator (IC37), -12V regulator (IC36) and 7805 (IC35), and solder a mini-ATX PSU outputs to the holes directly. It would cost about the same, and be a whole lot safer.

If you'd like more detailed instructions, I'd just need to know if you have an Issue 5 or Issue 6/7 PCB.

Re: Power supply for QL

Posted: Mon Feb 25, 2019 7:52 pm
by Jack_Free
that's really terrible, I might be afraid to join QL

Re: Power supply for QL

Posted: Tue Feb 26, 2019 1:42 pm
by drdivago
Hi,

Together with a friend we are looking at using the concept of using two PSUs to replicate the original outputs rather than the execution above (I agree it looks unstable and possibly dangerous...)

On the other hand I would like not to touch the QL board if possible, even if those changes are easily undoable.

Thanks

Ciao
Leo

Re: Power supply for QL

Posted: Thu Feb 28, 2019 2:41 pm
by Jack_Free
In any case, let me know how you are going.
A certain solution may be.
Would not it be wiser to use only trafo?
So how is it in the original PSU?

Re: Power supply for QL

Posted: Thu Feb 28, 2019 11:44 pm
by Dave
Jack_Free wrote:In any case, let me know how you are going.
A certain solution may be.
Would not it be wiser to use only trafo?
So how is it in the original PSU?


Designing a PSU that is going to be sold is a tricky business. There's a lot of regulations and certifications, and with power supplies they are not optional. You cannot self certify. The consequences of getting it wrong can be disastrous with people losing their homes or loved ones. That's why I won't do a power supply.

While it would be quite easy to do a copy of Sinclair's design, it simply isn't a very good system. Sure, it was cheap to make and it's held up REALLY well over 35 years. However, it is over-complicated, and it also forced design decisions onto the QL that just don't need to be made these days.

There's other ways to solve this problem.

Re: Power supply for QL

Posted: Thu Mar 07, 2019 12:01 pm
by Derek_Stewart
Jack_Free wrote:Hello,

I'm looking for a QL-friendly power supply, including the end cap.
Alternatively, some idea of how to make this resource from the new components.
Thank you
Jack

Hi Jack,

I have QL Power Supply, with a UK mains plug attached.

Price £10 plus postage

Send me a PM if you are interested.

Re: Power supply for QL

Posted: Thu Mar 07, 2019 8:02 pm
by Jack_Free
Thank you all for your help, I seem to have found out.
You can close the topic.
Thank you

Re: Power supply for QL

Posted: Thu Mar 14, 2019 10:33 am
by drdivago
Hi,

For those still looking for an original QL PSU, there is one on offer right now in eBay: https://www.ebay.co.uk/itm/sinclair-Ql-Power-Supply-9vdc-And-15-6ac/273757061075

Thanks

Ciao
Leo