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IBM 5150 not booting - power supply or motherboard needed? Any for sale...?

MartinToton

New Member
Joined
Aug 2, 2013
Messages
7
Location
Nottingham, UK
Hi All

My old IBM 5150 no longer boots up. It was working last week (its used on a weekly basis to drive some special hardware) but its not very happy at the moment.

When powered on the 'A' drive shows no signs of life and the monitor is 'white screen' (like it is when not connected to the PC) so its as though it is not being told what to do, so my first thought is the power supply has gone. The fan in the power supply which does spin, but other than that it shows no signs of life whatsoever, does the fan run off 'mains' before being transformed?

Does this sound like the power supply, or is it just as likely the motherboard?

Does anybody have a stash or working 5150 parts for sale to help resolve the problem?!

Many thanks

Martin
 

modem7

Veteran Member
Joined
May 29, 2006
Messages
7,858
Location
Melbourne, Australia
does the fan run off 'mains' before being transformed?
Depends on the power supply. If your power supply is the one supplied by IBM in the 5150, then the early versions of those power supplies were known for using a fan powered from mains AC voltage.

Does this sound like the power supply, or is it just as likely the motherboard?
Components other than those can be at fault too. For example, a short circuit in an expansion card.

Have you tried the diagnostic procedure at:
1. Goto http://www.minuszerodegrees.net/index.htm
2. Select link, 'IBM 5150 - Minimum Diagnostic Configuration'
 

GottaLottaStuff

Veteran Member
Joined
Apr 6, 2011
Messages
637
Location
Central Virginia, USA
Does it have a hard drive? A simple test is to unplug the motherboard power connectors and see if the power supply will spin the hard drive without the motherboard. If it doesn't have one, scrounge one up. It doesn't need a controller, it just has to physically plug in to the power supply to provide some load for it. If that makes any sense.
 

bjorn_and

Experienced Member
Joined
May 22, 2012
Messages
77
Location
Gothenburg, Sweden
I had really good use for this when I recently fixed my latest 5150 which I got almost for free as it was dead.

http://www.minuszerodegrees.net/5150_5160/MDC/minimum_diag_config.htm

Turned out to be just a shorted tantalum on the -12v line. The tantalum looked perfectly fine on the outside so I couldn't have found it just by looking.

Good luck!

Edit: I saw that following this guide was already suggested, so I just second that.

Björn
 
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