How to short a ps/2 keyboard fuze ?

  • Thread starter Thread starter JK
  • Start date Start date
J

JK

Hi

I have a motherboard (bought second hand) with a faulty ps/2 keyboard
port. I can use an usb keyboard, but

How do I repair this ? I have heard that a small fuze is located
inside the ps/2 box. Is that right ? hos does the fuze look like ?

A links to pictures ?

Thanking you in advance

best regards

John
 
JK said:
Hi

I have a motherboard (bought second hand) with a faulty ps/2 keyboard
port. I can use an usb keyboard, but

How do I repair this ? I have heard that a small fuze is located
inside the ps/2 box. Is that right ? hos does the fuze look like ?

A links to pictures ?

Thanking you in advance

best regards

John
Click to expand...

I would have doubts on it being a fuse. The first problem I would say would
probably be the keybaord.. if it works on other boards then it's not the
keyboard.
If it's not the keyboard then I would say it's the drive circut. To be
honest I dont even know if it's fused. If the computer is actually able to
start then I would leave it alone, cause that fault could drive signals in a
continual fashion and cause the board to not work properly.

Chances are it's the drive chip or maybee even a short somewhere (clean up
the mobo around the pins on the backside & check the underside of it where
they connect for damage)
 
I have a motherboard (bought second hand) with a faulty ps/2 keyboard
port. I can use an usb keyboard, but

How do I repair this ? I have heard that a small fuze is located
inside the ps/2 box. Is that right ? hos does the fuze look like ?
Click to expand...

Replace the word "inside" with "right next to", and you'll be happier.
It often looks like a small resistor, though it may be square or flat too.
Mine has "fuse" stencilled on the board right next to it.
A links to pictures ?
Click to expand...

What's the motherboard brand/model/revision?
 
Replace the word "inside" with "right next to", and you'll be happier.
It often looks like a small resistor, though it may be square or flat too.
Mine has "fuse" stencilled on the board right next to it.


What's the motherboard brand/model/revision?
Click to expand...

gigabyte bx2000+

but this asus group is so active.

Maybe you are able to see this picture:

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=3482783395&sspagename=STRK:MEWA:IT&rd=1

A guy repaired an asus a7v133a for me with the same problem. He said
he just shorted a fuze.


best regards

John
 
JK <(please reply said:
gigabyte bx2000+

but this asus group is so active.

Maybe you are able to see this picture:

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=3482783395&sspagename=STRK:MEWA:IT&rd=1

A guy repaired an asus a7v133a for me with the same problem. He said
he just shorted a fuze.


best regards

John
Click to expand...

On an Asus motherboard, these kind of fuses are used:

http://www.wickman-fuses.com/html/pptcsm.html

They are called Polyfuses, and this is a positive temp coefficient
material that open circuits when it gets hot, then goes closed
circuit when it cools off. It is a fuse that shouldn't need
replacement.

The surface mount ones shown on the URL above, have little semicircular
dimples on each side, and that feature helps to identify them from
other simple rectangular SMT devices on the motherboard.

There might be two polyfuses near the PS/2 and parallel port
connectors on your board. I think one polyfuse protects the two
PS/2 ports and a second one might protect the parallel port. You
can test the fuses with an ohmmeter, and they should read close to
zero.

Repairing one, by soldering a wire across it, is asking for
trouble. Your PSU has probably 20 amps available on +5V, and
if the keyboard cable ever shorts out, without proper fuse
protection somewhere in the circuit, then a copper track on
the motherboard will be burned black, and your keyboard port
will never get power again.

Looking at some old motherboards here, the polyfuse next to the
PS/2 port is labelled 1X1 or 110, implying it is a 1.1 amp part.
The dimensions I measure are around 2.8mm x 4.5mm, and an 1812
is the closest match to those dimensions.

http://www.wickmann.com/products/SMD1812.pdf

Apparently, you can order online from here:

http://www.wickmannusa.com/html/order.html

I suppose a Polyfuse could wear out, but look for other signs
of visible damage, like burned tracks or the like. If some other
component that draws +5V on the motherboard has burned its supply
track, that could deny power to the keyboard and mouse.

Good luck,
Paul
 
On an Asus motherboard, these kind of fuses are used:

http://www.wickman-fuses.com/html/pptcsm.html

They are called Polyfuses, and this is a positive temp coefficient
material that open circuits when it gets hot, then goes closed
circuit when it cools off. It is a fuse that shouldn't need
replacement.

The surface mount ones shown on the URL above, have little semicircular
dimples on each side, and that feature helps to identify them from
other simple rectangular SMT devices on the motherboard.

There might be two polyfuses near the PS/2 and parallel port
connectors on your board. I think one polyfuse protects the two
PS/2 ports and a second one might protect the parallel port. You
can test the fuses with an ohmmeter, and they should read close to
zero.

Repairing one, by soldering a wire across it, is asking for
trouble. Your PSU has probably 20 amps available on +5V, and
if the keyboard cable ever shorts out, without proper fuse
protection somewhere in the circuit, then a copper track on
the motherboard will be burned black, and your keyboard port
will never get power again.

Looking at some old motherboards here, the polyfuse next to the
PS/2 port is labelled 1X1 or 110, implying it is a 1.1 amp part.
The dimensions I measure are around 2.8mm x 4.5mm, and an 1812
is the closest match to those dimensions.

http://www.wickmann.com/products/SMD1812.pdf

Apparently, you can order online from here:

http://www.wickmannusa.com/html/order.html

I suppose a Polyfuse could wear out, but look for other signs
of visible damage, like burned tracks or the like. If some other
component that draws +5V on the motherboard has burned its supply
track, that could deny power to the keyboard and mouse.
Click to expand...

Thank you Paul. I now have an idea of the components.

I have last night bought second hand in my country an asus p3b-f with
a promise ata66 controller as a replacement for this motherboard. I
think that might work perfectly and the asus board leaves me more
overclocking freedom with a celeron 1200 tualatin (slot-T adapter), it
has also STR. I am thinking of 12x124 or 12x133 (with a suited
graphics card).

The gigabyte will maybe never be used any more. If yes, then with just
a 450 MHz P3 and with an usb keyboard (that I have). Since I do not
intend to buy more sdram, adapter and celerons tualatin.
So I have now 2 slot-1 board on funery: abit be6-ll with swollen
capacitors and now this gigabyte with faulty ps/2.

best regards

John
 
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