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IBM 5150 Line Voltage

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bobba84

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Hi guys,

I've bought a 5150 that is arriving from the U.S. next week. (I'm in Australia).

Due to the different line voltage, I was wondering if there is an internal jumper or anything to easily change the power supply to suit 240V?

If not, I'll have to use a transformer.

Thanks!
Bobby.
 
Well it can't be switched, but there was both 220-240V and 110-120 5150's.

I'd expect the change required is just a case of replacing a transformer(s) but finding the exact parts might be tricky. If it was me, I'd probably pull the 220V supply out of another machine - an old clone that's died. That way you'll be able to use the monitor power socket (handy if you plan to use an IBM 5151) without needing a 110V display.
 
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SpidersWeb said:
Well it can't be switched, but there was both 220-240V and 110-120 5150's.

I'd expect the change required is just a case of replacing a transformer(s) but finding the exact parts might be tricky. If it was me, I'd probably pull the 220V supply out of another machine - an old clone that's died. That way you'll be able to use the monitor power socket (handy if you plan to use an IBM 5151) without needing a 110V display.
Click to expand...

Just remember that if you get a switchable 120V/240V power supply, that does not affect the monitor power socket -- that will always match whatever your local line voltage is.
 
Early US 5150s used line-powered AC fans, so voltage there is important. As far as the SMPSU itself, I haven't looked, but I suspect that there's a way to wire them for 220V operation--most power supply makers usually provided some way to do this--but you're going to need to change that fan in any case.
 
Chuck(G) said:
Early US 5150s used line-powered AC fans, so voltage there is important. As far as the SMPSU itself, I haven't looked, but I suspect that there's a way to wire them for 220V operation--most power supply makers usually provided some way to do this--but you're going to need to change that fan in any case.
Click to expand...

With a shaded-pole AC motor, the frequency of the line power is what determines the speed of the fan, not voltage. So if you take an electric fan motor designed for 60 Hz 120V AC power and run it on 50 Hz 240V AC power, it will be running more slowly... and smoking, due to the double voltage burning up the coils! :eek:
 
With a shaded-pole motor, it's a combination of both voltage and frequency--or more properly, a combination of voltage, frequency and load that determines speed.

However, there's the matter of winding resistance, so you can't put 3 KV 60Hz AC on a fan rated for 120V 60Hz and expect it not to go poof. Putting 220V 50Hz on a 120V 60Hz fan will smoke the fan--the overvoltage is more of a factor than the 10 Hz frequency difference. If you look at old linear PSUs, you'll find that they're usually rated for 50/60 Hz--many use split primaries that can be connected in series or parallel.

On the other hand, I have taken 110V 25Hz motors and run them successfully on 240V 60Hz. Yes, they do run much faster.
 
Thanks for the feedback guys!

I'm thinking it's not worth it, as I don't want to modify it from it's original form too much. I was hoping it would be a simple wire or jumper change, but it doesn't sound like that is the case.

I've obtained a 110v converter to use. :)

Bobby.
 
I have one further question... Will running the 5150 at 50Hz matter? I have a step down that will convert 240v to 110v but it doesn't change the frequency?

Bobby.
 
I think most SMPS in PC's don't care, My 5150 and 5160's are rated 50/60 Hz, check the rating on the back of your machine. You could keep a look out for a 240V 63W 5150 PSU or a PSU out of a 5160 or 5162 will fit also.
 
Chuck(G) said:
Early US 5150s used line-powered AC fans, so voltage there is important.
Click to expand...
I don't think it has to do with "early", but with the manufacturer of the PSU. My European IBM PC 5150 from 1985 also has an AC-driven fan. It's the same PSU you can see in one of my blog entries on my website (http://www.retro-net.de/48.html) and was made by "GRESHAM LION".
 
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Could be--I remember going to the local IBM business office to order a half-dozen 5150s to be sent overseas and being told that the export model wasn't ready and that operating the US/Canada model on a step-down transformer would violate the warranty. That might have been marketing policy, but we went ahead and shipped the domestic ones overseas anyway. They worked fine.

Old hard disks like the Shugart SA1000 and SA4000 would have been a very different matter as they had AC motors in them.
 
Thanks guys. I do have a spare 5160 power supply, but it's the model with the loud, high rpm fan. I might run the 5150 supply alone and check the output voltages, and decide from there.

Bobby.
 
I have two US-spec 5150s that I've run for a decade on a step-down transformer via 240VAC/50Hz. That's not the problem - the problem is if one day you (or someone else) forgets to use it because you are so accustomed to IEC plug cords going straight into the wall. Same applies to the 5151 and 5153 displays. Here's my $0.02:

a) I've looked at modifying the PS design and consulted with my work colleague who is an EE and well-versed on the subject of switchers and the outcome is that although the main power flow path is easy to convert, the primary-side electronics would require a crude voltage divider added which may or may not work well. If I had a spare to experiment with I would try it as I personally think it would work.
b) I've considered swapping the internals from a common dual-voltage Baby AT supply. What stopped me is that I'm very reluctant to damage the authenticity of the PCs, especially given that these examples are pristine. The long, thin DC power wires coming out of the PS box would be a giveaway.
c) I have two small step-downs that I was hoping to attach the the back panels, but there's no room and it's an ugly mod.
d) The 5151 monochrome monitor is easy to convert and I've documented that about a year ago in another post. The 5153 CGA monitor is designed like a cheap common television and is not easily modified.
 
paul said:
The 5153 CGA monitor is designed like a cheap common television and is not easily modified.
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There's so much empty room in the 5153 that you can easily put a step-down transformer inside and re-wire the power connector to the step-down transformer. ;)
 
My 5151 is 240v. I'll have to be damn careful not to plug it in to the 5150's PSU.

What I might do is put a sticker or something over the IEC out connector. That way I shouldn't make that mistake.
 
Just use another power cord with the 5151 that plugs directly into the 240V in the wall. That way it won't have the right connector and you can't make a mistake. It's an idiot proof solution. :)
 
Stone said:
Just use another power cord with the 5151 that plugs directly into the 240V in the wall. That way it won't have the right connector and you can't make a mistake. It's an idiot proof solution. :)
Click to expand...

I've got a 5151 where someone has put one of those plugs on it, and it's actually quite annoying lol
There is no switch on a a 5151 to turn it off or even a light to let you know it's running. Quite easy to leave the thing turned on for days without even realizing :(
 
I've got rackmount power strips with female IEC connectors that are used for both 240 and 120V. The only difference is the plug on the end of the main power cord. Can you say poof?
 
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