IBM autoswitch powersupply?

[per]

I recently aquired a computer using a powersupply with the IBM number of 62X1139. This computer is from America, and the rear of the computer says it takes "Range 115" from 100V to 125V AC. However, the PSU itself got markings for both 110V and 220V AC.

(It's not my unit that is pictured, but it's similar)

Does this suggest that it supports autoswitching between 110V and 220V AC, or is it just a default label used on both the 110V AC versions and 220V AC version? There are no switch anywhere on the PSU, and I haven't been able to open it up to check if there are a switch inside.

The last time I encoured this problem (that time with a third-party PSU), I decided to test out 220V AC, and the PSU blew up. I don't want this to happen again, so I would like to ask if any of you can confirm that it does support 220V AC before trying it out.

 

[Ole Juul]

It is of course common to see 220 ratings on parts. However, on that label it certainly looks like it is intended for actual 220v input. Is there a movable wire inside the box?

 

[MikeS]

I would definitely not assume that it's an autoswitching supply; the label on the PSU would suggest that it's 110/220 capable, probably selected with an internal jumper wire, while the case label indicates that it is (or was) set for ~110V operation. Open it up and look inside.

 

[per]

It is of course common to see 220 ratings on parts. However, on that label it certainly looks like it is intended for actual 220v input. Is there a movable wire inside the box?

I'm still not convinced that it's autoswitching. I bet there is a wire inside, but I don't have the required security-screw screwdrive required to open it.

I have confirmed that it works with the step-down coil I have. In lack of an American PSU cable, I had to attach a cable directly to the "sukkerbit"* in the coil.

(* A norwegian term for a special kind of parallel splice joint on electric wires, that directly transelates to "sugar-bit" or "cube of sugar". The name derives from the fact that the joint is usually white of color, and almost a perfect cube in the case of a double-joint. Here is an example of one with 12 parallel joints: http://shopher.no/images/Sukkerbit_12pk_400x.jpg)

 

[Chuckster_in_Jax]

I'm still not convinced that it's autoswitching. I bet there is a wire inside, but I don't have the required security-screw screwdrive required to open it.

I have one of those IBM power supplies made by Astec (not that model though). You will need a Security Torx bit to open it up. Here in the states there is a company called Harbour Freight that sells an entire set of them for around $10.

 

[Chuck(G)]

Autoswitchers usually specify a voltage range, something like "90-270VAC" with both ends of the range outside of the usual nominal distribution voltage. That's not what you have.

 

[Dwight Elvey]

Hi
Just grind the head off the screw. Screws are replaceable.
If you find the jumper wire, be sure to mark the case that
you've done it. Many of the older supplies will blow if
set for 220 and run at 115v( been-there-done-that ).
Dwight

 

[nige the hippy]

I usually run a hacksaw a few times over the heads to put a slot in, then take it out with a "primitive" screwdriver.
A tamperproof torx set would be a worthwhile investment though, for many reasons, only some of them "Compaq".