User avatar
A1-X1000
Toronto, Canada

Posted Fri Jul 19, 2019 8:47 pm

So wanting to replace my old and trusty original A4000 PSU with A4000 ATX PSU power adapter I purchased a micor-ATX psu that fits nicely into the A4000 PSU chasis BUT....

1-tried connecting micro-ATX and nothing..PSU not starting at all nor A4000 so tried another dull size ATX PSU and same thing
2- contacted Amigakit and they told me it was some 'sense' thing with newer PSU's but I had my suspicions
3- tried starting the PSU without connecting to A4000 and voila PSU started up no problem with following voltage readings:

Grey - +5.21v
Blue- -11.32v
Yellow- +12.14v
Red- +5.23v
4- let Amigakit know and they said these readings were fine and adapter was working ok but offered no help as to why it wasn't powering on my A4000

So long story over I turn this mystery over to my fellow amigans and hopefully I'm not the only one in the world this has happened too?&^! :-D :-P ..how come this kinda luck never happens when I buy a lottery ticket ;-) :roll:
Last edited by A1-X1000 on Sat Aug 10, 2019 9:18 pm, edited 1 time in total.

User avatar
Technoid

Posted Tue Jul 30, 2019 5:00 am

What brand and model is the atx psu's you have tried?
A1-X1000 wrote:So wanting to replace my old and trusty original A4000 PSU with A4000 ATX PSU power adapter I purchased a micor-ATX psu that fits nicely into the A4000 PSU chasis BUT....

1-tried connecting micro-ATX and nothing..PSU not starting at all nor A4000 so tried another dull size ATX PSU and same thing
2- contacted Amigakit and they told me it was some 'sense' thing with newer PSU's but I had my suspicions
3- tried starting the PSU without connecting to A4000 and voila PSU started up no problem with following voltage readings:

Grey (what you call purple)-+5.21v
Do you mean that the cable from the ATX PSU is grey and the cable on the adapter is purple?
Purple on the ATX connector is 5v vsb and that would confuse the heck out of your amiga, since it would get pwr_good signal and no voltages as soon as you flip the powerswitch on the back of the atx psu.
A1-X1000 wrote: Blue--11.32v
this is way low, the psu probably regulates from the 3.3 rail...
A1-X1000 wrote: Yellow-+ 12.14v
Red-+5.23v
4- let Amigakit know and they said these readings were fine and adapter was working ok but offered no help as to why it wasn't powering on my A4000
The adapter might be technically working buut these readings arn't "fine" :roll:
I really hate when you are expected to be an electrical engineer just because you have an amiga :cry:
A1-X1000 wrote: So long story over I turn this mystery over to my fellow amigans and hopefully I'm not the only one in the world this has happened too?&^! :-D :-P ..how come this kinda luck never happens when I buy a lottery ticket ;-) :roll:
I do have an amigakit atx to a4k adapter cable I haven't had time to test it, but it seems to be correctly wired ( i do wish it connected all voltage cables and not just one single) but I have experienced atx psu problems with a hacked square din atx cable.
When I initially made it I used a diffrent psu, and ran into problem because the newer was expecting 3.3 load.

Amiga HW goes insane in the membranes if it does not get more than 4.75v :p

User avatar
A1-X1000
Toronto, Canada

Posted Sat Aug 10, 2019 9:17 pm

Update:

got around to try a full sized ATX PSU tonight and readings as follows when not connected to anything again:

Grey -+5.11v
Blue--11.52v
Yellow-+ 12.21v
Red-+5.11v

and yet again like the micro-ATX PSU my A4000 won't boot up at all. Tried attaching an old 'real' hard drive to see if some extra load draw would kick it up but same thing.

User avatar
A1-X1000
Toronto, Canada

Posted Sat Aug 10, 2019 9:23 pm

Technoid wrote:
A1-X1000 wrote: Blue--11.32v
this is way low, the psu probably regulates from the 3.3 rail...

well with the full ATX PSU I got a better -11.52V but still not as good as I was hoping..

User avatar
Technoid

Posted Thu Aug 15, 2019 2:46 pm

Okay, heres the question that I assumed....

Do your amiga4k work with the original PSU?

User avatar
A1-X1000
Toronto, Canada

Posted Thu Aug 15, 2019 9:18 pm

Technoid wrote:Okay, heres the question that I assumed....

Do your amiga4k work with the original PSU?

ya was working fine & after trying the adapter the 1st time I got scared something blew so immediately hooked up my original PSU and thankfully she booted up :o ..that was a big relief

User avatar
Technoid

Posted Thu Jul 23, 2020 4:29 pm

Hey A1-X1000, did you ever sort you adapter cable problems out?

I finally got around to testing my amigakit atx ->A4000 adapter and my A4000 starts and works which reminded me of your problems.

User avatar
A1-X1000
Toronto, Canada

Posted Fri Jul 24, 2020 11:51 am

Technoid wrote:
Thu Jul 23, 2020 4:29 pm
Hey A1-X1000, did you ever sort you adapter cable problems out?

I finally got around to testing my amigakit atx ->A4000 adapter and my A4000 starts and works which reminded me of your problems.
glad you got it working ok... could never get my A4000 with that adapter to boot up my A4000 for whatever reason so still using my trusty original PSU which has been recapped....though my audio is all low and muffled now since that scary experience I noted above with the adapter...have to take some time to strip it down and investigate...think it s the pre-amp that blew? doubt its the capacitors since they were recently replaced but we'll see





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