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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: RetroNinja on May 13, 2023, 05:43:21 PM

Title: A2000 power supply, what's good enough?
Post by: RetroNinja on May 13, 2023, 05:43:21 PM

Hello,
I have an A2000 power supply that measures less than than what it should. Referring to https://retrowiki.net/doku.php?id=rw:comp:amiga:power (https://retrowiki.net/doku.php?id=rw:comp:amiga:power) my
+5v = 4.84v   :(
+12v = 11.45v   :(
-12v = -11.18v   :(
-5v = -5.07v  :)
My testing involves attaching an old SCSI drive to the power supply so there is a load to start it. When testing with a different power supply my voltages are where they should be (with HDD attached).

So, are these dangerous voltages? Are they within acceptable norms?

I expect to add a memory card A25000 (2MB) and maybe swap 1 FDD for a gotek, maybe an A2091 w/ZuluSCSI in the future. Of course as I write this I've kinda made up my mind that I'll replace it. Regardless, what's the standard take on the voltages?

Thanks!

Title: Re: A2000 power supply, what's good enough?
Post by: mechy on May 13, 2023, 09:37:34 PM

Low voltages are not dangerous and these power supplies do not usually go high voltage and damage anything.
The +5 is the main voltage and preferably need to be close to 5v.... 4.92 is about as low as i like to see it. +12 i like to see 11.9+.
recapping might help the psu,but there is adjustment inside for +5,but if memory serves it will also affect +12,so check both when adjusting.

Title: Re: A2000 power supply, what's good enough?
Post by: sheepz on June 06, 2023, 09:57:22 AM

Hi

I recapped my A2000 PSU, I was had as like yors everything was within 10%.

Mine had a TF536, CD rom and ZuluSCSI on my Hardframe SCSIO controller and had no issues.

Regards

Barry

Title: Re: A2000 power supply, what's good enough?
Post by: Pat the Cat on June 13, 2023, 02:44:52 PM

Quote from: RetroNinja on May 13, 2023, 05:43:21 PM

So, are these dangerous voltages? Are they within acceptable norms?

I expect to add a memory card A25000 (2MB) and maybe swap 1 FDD for a gotek, maybe an A2091 w/ZuluSCSI in the future. Of course as I write this I've kinda made up my mind that I'll replace it. Regardless, what's the standard take on the voltages?

Thanks!

Not dangerous, if a component doesn't have the voltage to operate properly, it just won't work very reliably. Components vary individually on the tolerances, some are a more fussy than others, so some Amigas would work at that voltages and some would not.

There are electrolytic capacitors everywhere. Even in the power supply. They age, and that's why it's low.

A recap of the PSU at least should restore ll the values back up.

A gotek takes less power than a floppy. Not an issue to do that. A2091, well... Probably OK. Depends how much service it's already had, partly.

Where you would likely have problems is fitting something like an 040 accelerator. Notoriously greedy and hot running,.