IBM PC 5150 disk drive causing power supply to not work

[solarpv]

I have been checking out a few IBM PCs I have. I found when I powered up the power supply seemed dead.
when I disconnected the disk drive the computer powered up. I have 4 IBM full height disk drives that cause this.
Anyone know why?
Thanks

 

[Chuck(G)]

Are you using the original 62.5 watt 5150 PSU? What else to you have in the boxes? If you disconnect the motherboard and connect only the hard drive up to the PSU, does it spin up?

 

[solarpv]

Hi,
These are original setups that worked in the past. There are no hard drives. Just 2 full height floppy drives. I took the drives out of the non- working unit and tested them in a working unit.
When I put them, one at a time, in the working unit, the power supply did not turn on. When removed the computer worked fine. I tested them as drive A with a terminator resister installed.

 

[modem7]

Maybe each of your four faulty floppy drives has a short circuit in it, overloading the power supply. Four is a lot!

Your "IBM PC 5150" and "4 IBM full height disk drives" suggests to me that the drives are rebadged Tandon TM100-2's.
If that is the case, read the 'Short-circuit capacitors' section of [here].
Over many years, I have had the one of the two capacitors go short circuit on several of my TM100-2's, and recently, member tonata discovered the same with one of his TM100-2's.

 

[solarpv]

Hi,
Thanks for the reply. I did inspect the capacitors visually and did not see any thing burnt. That's as far as I can go with that. I do not plan to solder and replace the part. I was just curious what caused the problem and if there was an easy fix. I will probably give these 4 drives to anyone that wants them locally. I think shipping them will be to expensive.
I have 2 working 5150s with 2 drives each and now 2 spare working floppy drives.