Stacy nano psu upgrade

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Gitbizy
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Joined: Mon Aug 09, 2021 4:22 pm

Stacy nano psu upgrade

Post by Gitbizy » Fri Sep 03, 2021 11:49 pm

I completed the work today on my Stacy 4144. Removed the J17 header and soldered in wires to

2 +5
4 +12
5 -12
10 gnd
Ran these to a nano PSU with an adapter board that allows me yo turn the PSU on and off
When I power the Stacy I get a white screen and no floppy activity

Please note-I don’t know for certain that my monitors and the monitor to DB9 adapter are working properly but I am going by floppy activity and nothing happens when I power on the Stacy.

Since I don’t have the LCD monitor hooked up due to the psu swap hard to know if I’m getting an actual boot up.

First question.
I have seen people state they have powered the Stacy via the floppy connector. Correct me if I’m wrong but the floppy connector only has 5 and gnd. The 12v looks unconnected in the schematic.

Can someone confirm that this approach works, just 5 and gnd via floppy?

Secondly, I connected the nano pico psu to the j17 pins above.
Pins 1-3 all tie to +5 and I ran the wire to 1. 9-11 are grounds and I ran the ground from the psu to 10.

Do I need to run the power to all 3 inputs and ground to all 3 grounds?

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Darklord
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Re: Stacy nano psu upgrade

Post by Darklord » Sat Sep 04, 2021 4:23 pm

I used a Pico for a while, hooked up to the 2nd set of floppy leads on my STacy
and it worked fine. +5 and ground were all that were needed, IIRC. I got this
information from Alan H. at Atari Forum. When I say "fine", I mean I was using
it to drive a color monitor from the external video port on my STacy, not the
original LCD.

There are 2 sets of floppy leads because there actually was a STacy model
with 2 internal floppies instead of 1.

About powering the original LCD. I tried that with the Pico and failed. All I
got was a black screen. I wasn't intelligent enough to figure out how to get
the Pico to do the negative -20 (or was it -12?) that's in that circuit. Really
weird stuff there, IMHO.

HTHs.
Welcome To DarkForce! www.darkforce.org "The Fuji Lives.!"
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derkom
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Re: Stacy nano psu upgrade

Post by derkom » Sat Sep 04, 2021 4:55 pm

Gitbizy wrote:
Fri Sep 03, 2021 11:49 pm
I have seen people state they have powered the Stacy via the floppy connector. Correct me if I’m wrong but the floppy connector only has 5 and gnd. The 12v looks unconnected in the schematic.

Can someone confirm that this approach works, just 5 and gnd via floppy?
Correct that +12V on the FD connectors is not connected to anything. But you don't need it. I can confirm, as @Darklord has, that the Stacy can run fine (with external monitor) when powered solely with +5V via the FD connector.
Do I need to run the power to all 3 inputs and ground to all 3 grounds?
By "all three inputs", do you mean all three of the +5V pins or all three of +5V, +12V, and -12V? All the +5V pins are tied together, so you don't technically need to power all of them, as long as your PSU can provide enough current over just one. Just the same, I did connect all three when I did my own picoPSU connection. The pico has the pins available, so why not use them?

If you were referring to the three separate voltages, then no, you really only need the +5V to get the Stacy running (with external monitor). I don't know if the +12V is used for anything other than the +12V line on the monitor out, and I don't know if -12V is used for anything at all. Just the same, I hooked it up.

Do note that if you're using something like an ubeswitch or exxos's VGA adapter on the monitor output, those boards do need the +12V on that port.

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derkom
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Re: Stacy nano psu upgrade

Post by derkom » Sat Sep 04, 2021 4:58 pm

Darklord wrote:
Sat Sep 04, 2021 4:23 pm
I wasn't intelligent enough to figure out how to get
the Pico to do the negative -20 (or was it -12?) that's in that circuit. Really
weird stuff there, IMHO.
I think your real difficulty there would be the 85V AC @ 590Hz that the EL backlight needs. Good luck! :lol:

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Darklord
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Re: Stacy nano psu upgrade

Post by Darklord » Sat Sep 04, 2021 6:25 pm

derkom wrote:
Sat Sep 04, 2021 4:58 pm

I think your real difficulty there would be the 85V AC @ 590Hz that the EL backlight needs. Good luck! :lol:
Yeah, as I mentioned, never got that part to work... Oh well... :)
Welcome To DarkForce! www.darkforce.org "The Fuji Lives.!"
Atari SW/HW based BBS-Telnet:darkforce-bbs.dyndns.org 520

Gitbizy
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Joined: Mon Aug 09, 2021 4:22 pm

Re: Stacy nano psu upgrade

Post by Gitbizy » Wed Sep 15, 2021 4:56 pm

Good news... I was able to get the Stacy to power up after I hooked up the +5 and GND via the floppy connector. Now I can breathe a sigh of relief that I didn't fry the Stacy.

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Darklord
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Re: Stacy nano psu upgrade

Post by Darklord » Thu Sep 16, 2021 4:42 pm

Gitbizy wrote:
Wed Sep 15, 2021 4:56 pm
Good news... I was able to get the Stacy to power up after I hooked up the +5 and GND via the floppy connector. Now I can breathe a sigh of relief that I didn't fry the Stacy.
Congratulations!

PS Where's the pictures? We *love* pictures man! :)
Welcome To DarkForce! www.darkforce.org "The Fuji Lives.!"
Atari SW/HW based BBS-Telnet:darkforce-bbs.dyndns.org 520

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