Working on a sony PSOne video display with no documentation.

First problem was a tiny fuse of some sort; it was open. Shorted it with
a wire. From the way the power supply was behaving (pulsing on and off),
I decided that some component had shorted, ant that's what took the fuse
out.

By some judicious cutting of traces, I was able to isolate one component
that was shorted (it connecetd between the voltage bus and ground), and
by cutting one of the traces to it, the whole display fired up and
seemed to work just fine.

Now I need to know what that part is so I can replace it.

It looks like a black rectangular tantalum surface-mount cap, except the
the letters printed on it, and the component designator on the board by
it, aren't right.

There's one obvious tantalum cap on the board. Its designator is "CP1";
this thing is "DP1", and on it are some odd symbols followed by "133",
and below that the letters "ZHU".

If it were a capacitor, then one of the two would be "CP2", but this is
"DP1".

So I'm thinking "diode", but I have no idea what specs it should have.

Note again that the display is working fine without it, but still, I'd
like to get it fixed properly.

Any idea what it is?

thanks, Isaac

"Isaac Wingfield" wrote in message
...
Working on a sony PSOne video display with no documentation.

First problem was a tiny fuse of some sort; it was open. Shorted it with
a wire. From the way the power supply was behaving (pulsing on and off),
I decided that some component had shorted, ant that's what took the fuse
out.

By some judicious cutting of traces, I was able to isolate one component
that was shorted (it connecetd between the voltage bus and ground), and
by cutting one of the traces to it, the whole display fired up and
seemed to work just fine.


I would say that it is almost certainly a diode, and if it's right after the
fuse, on the main feedline coming in from the power supply, then its purpose
will be reverse polarity protection - and it's probably done its job. Ask
the owner if they tried a " wrong " power supply in it ...

Assuming that it is a diode, and even being a surface mount type, it should
have some kind of polarity marker on it, either a stripe at one end, or a
chamfer on the case, then any general spec surface mount silicon power diode
will do. It would probably be rated something like 100v, 1 amp. It
should be connected cathode to rail, anode to deck, so that it is not
conducting under normal circumstances.

Arfa
Now I need to know what that part is so I can replace it.

It looks like a black rectangular tantalum surface-mount cap, except the
the letters printed on it, and the component designator on the board by
it, aren't right.

There's one obvious tantalum cap on the board. Its designator is "CP1";
this thing is "DP1", and on it are some odd symbols followed by "133",
and below that the letters "ZHU".

If it were a capacitor, then one of the two would be "CP2", but this is
"DP1".

So I'm thinking "diode", but I have no idea what specs it should have.

Note again that the display is working fine without it, but still, I'd
like to get it fixed properly.

Any idea what it is?

thanks, Isaac

On Thu, 26 Jan 2006 20:22:12 -0800, Isaac Wingfield
wrote:

Working on a sony PSOne video display with no documentation.

First problem was a tiny fuse of some sort; it was open. Shorted it with
a wire. From the way the power supply was behaving (pulsing on and off),
I decided that some component had shorted, ant that's what took the fuse
out.

By some judicious cutting of traces, I was able to isolate one component
that was shorted (it connecetd between the voltage bus and ground), and
by cutting one of the traces to it, the whole display fired up and
seemed to work just fine.

Now I need to know what that part is so I can replace it.

It looks like a black rectangular tantalum surface-mount cap, except the
the letters printed on it, and the component designator on the board by
it, aren't right.

There's one obvious tantalum cap on the board. Its designator is "CP1";
this thing is "DP1", and on it are some odd symbols followed by "133",
and below that the letters "ZHU".

If it were a capacitor, then one of the two would be "CP2", but this is
"DP1".

So I'm thinking "diode", but I have no idea what specs it should have.

Note again that the display is working fine without it, but still, I'd
like to get it fixed properly.

Any idea what it is?

thanks, Isaac


Without seeing it I'd say it's a Varistor.

Basically it's a voltage dependent resistor, a kind of surge protector
- they invariably go short circuit.





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