EIII Powersupply

[tychogrey]

Hi there,

does anyone know which powersupply I can use for my EIII?
The old one is out of stock.
I live in Germany, so a trader in Europe was fine.

M.

[ddvdave]

I found this power supply from Arrow Electronics:

http://www.arrow.com/item/detail/sl-power-electronics/gpc80cg

It has the correct voltages (+5, +12, +15, -15), however it is an all-switching PSU.

This post seems to imply the EII needs a linear PSU for the +/-15v lines:

I now know the difference between switching and universal power supplies, and why the audio portion of the EII power supply needs to be linear, and everything else is switched. So....

It seems strange that this guy http://www.synther.org/emulator2.html was able to use an all-switching PSU in his EII. (MeanWell T-60C). I would have assumed that any analog components would require a linear PSU regardless if it's in EII or EIII.

Can anyone shed more light on the EIII PSU requirements? Will a switching PSU work for the +/-15v analog power?

-Dave

[kdk]

As long as there's enough filtering on a switching PSU to get rid of line noise, shouldn't it work?

Every sound card in a computer has a switching power supply, right?

[ddvdave]

As long as there's enough filtering on a switching PSU to get rid of line noise, shouldn't it work?

Yes that's true. In fact, I think 80sboy may have been mistaken in his assessment. The EIII uses only a switching PSU:

EIII uses a switching power supply. We do not repair these supplies at the factory...

However, it can also depend on the load. If the EIII isn't drawing enough power from the PSU, the PSU might not have enough load to function properly. Switching PSUs have both minimum and maximum load specifications. The Arrow Electronics PSU has only a 1A minimum current draw requirement on the 5V line. No other requirements on the other outputs.

The Condor 130C PSU 80sboy tried initially may have been oversized. It has a 3A minimum on the 5v line and is a 130W PSU.

If I have time, I will take an ammeter to determine exactly how much current is drawn (on average) by each of the PSU lines, to better determine what rating of PSU will be optimal.

-Dave

[ddvdave]

I am still searching for a new PSU that will work in the EIII (or EII). From the label on the original EIII PSU, the specs read:

+5V/15A
-15v/1A
+15V/1.5A
+12V/5A

Max output power: 150W.

So this means the PSU in the EIII is a 150W PSU.

The closest thing I have found is the Power-One MAP110-4015, however I cannot find any suppliers for this and it is marked "Obsolete" at Mouser Electronics (Online/USA).

I have called Power One and left a message inquiring about the availability of this particular PSU. If I hear anything positive back, I'll respond to this thread.

-Dave