You have been directed to this web page because it has been determined that there is a short circuit on the +12 volt line of your 5150/5160 motherboard.

We know that the short circuit is on the motherboard because you were earlier instructed to remove all expansion cards from the motherboard.

It is very highly likely that the tantalum capacitor on the +12 volt line of your motherboard is the component that has become short circuit.
Faulty tantalum capacitors is a very common problem with the 5150 and 5160 motherboards.

Visually inspecting the tantalum capacitors may (repeat: may) reveal the faulty capacitor.
In some cases, the faulty tantalum capacitor may only have a small black eye/hole, as pictured below.



But the faulty tantalum capacitor may have absolutely no visual indication of failure.


5150 motherboard (PC) - type 16KB-64KB

This is the early version of the 5150 motherboard. It is marked "16KB-64KB CPU"
On this motherboard, sitting on the +12 volt line are: all RAM chips, and five tantalum capacitors.
Any of those may have gone short circuit, however history suggests that the short is most likely in one of the five tantalum capacitors.
Click here to see a photo that shows the five capacitors.
On this motherboard, the four of the five that are grouped together, are very important to the operation of the RAM on the motherboard.
I suggest that you replace all five capactors with new ones. The capacitors are of value: 10µF/16V
They need to be inserted correctly - positive leg into positive hole and negative leg into negative hole. Click here to see a photo.


5150 motherboard (PC) - type 64KB-256KB

This is the later version of the 5150 motherboard. It is marked "64KB-256KB CPU"
On this motherboard, only one component is on the +12 volt line, and that component is a tantalum capacitor.
Click here to see a photo that shows the capacitor.
The capacitor is not critical to the operation of this motherboard, and this motherboard can operate without it.
Remove the capacitor either by desoldering, or by using a pair of sidecutters to cut the capacitor off the board.
Your motherboard should work after the capacitor has been removed.

Should you later wish to solder in a replacement capacitor (the ideal situation), then click here for replacement details.


5160 motherboard (XT)

On a 5160 motherboard (of both types), only one component is on the +12 volt line, and that component is a tantalum capacitor.
Of the many tantalum capacitors on this motherboard, it is the one labelled C56
The capacitor is not critical to the operation of this motherboard, and this motherboard can operate without it.
Remove the capacitor either by desoldering, or by using a pair of sidecutters to cut the capacitor off the board.
Your motherboard should work after the capacitor has been removed.

Should you later wish to solder in a replacement capacitor (the ideal situation), then click here for replacement details.