Swapping PSUs among LC/Performas

[ArmorAlley]

Hi all

I need to get a new PSU for my Performa 475 (or, at least, I suspect that I do). I have an LCIII. Are the PSUs between the two interchangeable? The values written on them are a little different but, from what I have read, it seems that the LCIII PSU will work in the P475.

I would like to test the P475 PSU in the LCIII. Is this a bad idea? How about the LCIII PSU in the P475 until I can order one from uniserver?

Thanks for your help

aa

 

[Elfen]

For testing purposes it should be fine. But not for a swapping as a replacement. The LC 475 needs a little more current than the LC III, if you swap it the LC 475 will run hotter and burn out the PSU faster.

 

[ArmorAlley]

Hi Elfen,

Thanks for this. You confirmed my suspicions.

I also have a NewerTech QuadDoubler in there, so I may wait until I get a new PSU.

Many thanks

 

[Elfen]

Uniserver can tell you how to fix your PSU or beef it up (bigger caps and other things replacement). He also has a few PSU he mentioned that he has for sale. I forget where he posted that.

 

[djhaloeight]

I don't think it makes one bit of difference if you use the LCIII PSU in the 475. Both machines have the same case, same style internal peripherals, the only difference being the processor generation. From what I've gleaned on their specs, they both run at the same 50 watts maximum.

 

[djhaloeight]

Apple's own technical specification pages show they both use a maximum of 50 watts, while the 475 actually uses less amps.

LCIII: http://support.apple.com/kb/SP209

475: http://support.apple.com/kb/sp244

 

[uniserver]

I think this is a super cool article that talks about switch mode power supplies.

https://www.mikesarcade.com/cgi-bin/spies.cgi?action=url&type=info&page=psrepair.txt

 

[ArmorAlley]

Hi all,

Both power supplies are from Astec and have the following specs:

Mac | PSU Model Nr | Apple Part Nr | Output +5V -5V +12V

LCIII | AA16251 | 614-0003 | 3.75A 0.075A 0.78A

P475 | AA19140 | 614-0028 | 4.75A 0.075A 1.0A (and I wonder if the 475 in the machine name comes from the +5V ampage...)

 

[Juror22]

I think this is a super cool article that talks about switch mode power supplies.

https://www.mikesarcade.com/cgi-bin/spies.cgi?action=url&type=info&page=psrepair.txt

Now I have to try and fix my power supply… Thanks Uniserver

 

[Elfen]

(and I wonder if the 475 in the machine name comes from the +5V ampage...)

It does. (Verified it with my LC475. Its safe to assume that the Q475 is the same too.)