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Lisa 1.8a PSU clone by Warmech

mvwijland

New member
I am building the Lisa 1.8a PSU Clone as designed by Warmech and I have a question. I have sourced all items as mentioned on the site: https://github.com/warmech/lisa-hardware/tree/main/LisATX - Pico ATX PSU Replacement

My question is, and i hope somebody has also created this replacement PSU, how to connect the Pico ATX to the board? Is it soldering the bottom of the pico ATX one-on-one to the board?

If any one as also created this power supply, i would very much appreciate a number of pictures? Also of the components that are covered by the Pico ATX/
 

macmike

New member
Hi, yes i build this clone too. I put in a ATX-Connector (male) in the big PCB. Then you have to desolder the two ATX Connectors out of the Pico ATX and put in the big one from the opposite side. The 4-Pin connector is useless.
I will send you some pictures tomorrow.

Regards,Michael
 

mvwijland

New member
Hi, yes i build this clone too. I put in a ATX-Connector (male) in the big PCB. Then you have to desolder the two ATX Connectors out of the Pico ATX and put in the big one from the opposite side. The 4-Pin connector is useless.
I will send you some pictures tomorrow.

Regards,Michael
Great, thanks, pictures much appreciated.
 

macmike

New member
Hi,

i must correct my answer. I changed the connector in the Pico-ATX because it don´t fit in the one i used on the Lisa-PCB.
Please take a look at the pictures.

Regards, MichaelLisaPS1.jpg
 

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mvwijland

New member
Oke, great, this helps me a lot. I will finish the power supply. and hopefully the Lisa will come back to live.
 

mvwijland

New member
@macmike
Hi,

i must correct my answer. I changed the connector in the Pico-ATX because it don´t fit in the one i used on the Lisa-PCB.
Please take a look at the pictures.

Regards, MichaelView attachment 72248
Thanks MacMike for helping me out. I just finished building this PSU and tested the 33, 5, -5, 12 -12 rails and all looks good.
But then I checked the schematic and saw a -100V and +300V.

Are these currents that come from the videoboard in the Lisa?
 

stepleton

Well-known member
But then I checked the schematic and saw a -100V and +300V.

Are these currents that come from the videoboard in the Lisa?
Those are for video focus and contrast. The Lisa PSU does not make them --- those voltages just go into the PSU, pass through a pair of potentiometers that stick out the back of the Lisa so that the user can make an adjustment, and then they go right back out of the PSU. It's wholly unrelated to anything else the PSU does and there is no electrical connection to the "regular" PSU bits.

I'm sure the good folks at DataPower got a chuckle out of it when they first saw this as part of the spec for the 1.8A supply.
 
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