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Ohai!
Posted: Sun Mar 01, 2020 8:34 pm
by Brad
Brad from Cheltenham,
Been after a QL for a while. Just nabbed one, bare bones, no PSU even and no guarantee of even works
vanpeebles says I just need a 5v power supply? Any pointer appreciated!
Cheers.
Re: Ohai!
Posted: Sun Mar 01, 2020 9:31 pm
by vanpeebles
Welcome! A good search of fhe forum is needed, I’m sure someone tried something similar and broke a QL. You can trim down a 3 pin fan connector to fit the socket.
Re: Ohai!
Posted: Mon Mar 02, 2020 6:36 am
by Brad
Yeah there’s loads of info on here. Sounds tricky but doable, long as I’m careful.
Re: Ohai!
Posted: Mon Mar 02, 2020 8:45 am
by vanpeebles
viewtopic.php?f=2&t=1231&start=10&hilit=replacement+psu
Might be handy, you can also try a wanted post in the wanted section for a proper PSU.
Re: Ohai!
Posted: Mon Mar 02, 2020 8:55 am
by Pr0f
You need a power supply that can provide 9v DC with at least 2A, and 12-15V AC (this voltage is rectified and regulated in the QL to provide +12V and -12V for the serial ports, video circuitry and bias for the Microdrives)
Fan connectors do seem to work after a fashion
Re: Ohai!
Posted: Mon Mar 02, 2020 11:53 am
by tofro
Pr0f wrote:You need a power supply that can provide 9v DC with at least 2A, and 12-15V AC (this voltage is rectified and regulated in the QL to provide +12V and -12V for the serial ports, video circuitry and bias for the Microdrives)
That tranlates to
You can get away with 5V only, if you can live without serial ports, no microdrives, and RGB-TTL as video output.
Tobias
Re: Ohai!
Posted: Mon Mar 02, 2020 11:57 am
by Pr0f
tofro wrote:Pr0f wrote:You need a power supply that can provide 9v DC with at least 2A, and 12-15V AC (this voltage is rectified and regulated in the QL to provide +12V and -12V for the serial ports, video circuitry and bias for the Microdrives)
That tranlates to
You can get away with 5V only, if you can live without serial ports, no microdrives, and RGB-TTL as video output.
Tobias
You can't pipe 5V into the rear power connector directly - you will need to modify the 3 pin regulator socket to do that. But yes, if you remove the 5v regualtor on it's heatsink, you can apply 5 volt power there and run the QL board.
Re: Ohai!
Posted: Mon Mar 02, 2020 12:46 pm
by Brad
Might go the 5v route just to see if it powers up, keyboard works etc. Long term I'd like to have everything working just because I don't like having half working equipment.
Sounds like a minor board mod to do this though, which I wanted to avoid. If I put 9v into it in the normal fashion, will I get the 5v to where it needs to be, and avoid having to mod the board?