help id'ing a diode from a Toshiba laptop (see pic)

[Carl]

Picture here:

http://www.flickr.com/photos/44152487@N00/323329166/

I burned this one up by supplying it -19V (mistakening reversed the
polarity when fixing/resoldering a break in the power cord connector
-doh!)

Perusing the digikey catalog, I assumed it was a toshiba semiconductor
schottkey diode CMS01.

It had an S1 inscribed on it. Even though the dimensions were'nt quite
the same, I gave it a shot.

I've since shorted the 2 CMS01's, so that tisn't it. The CMS01 worked
fine until the laptop drew more current on AC power; it worked fine
allowing the battery to be charged; and on low power app's.

Can anyone help id'ing this component?

Its in parallel with (2) k-ohm resistors on a 19V P15 toshiba notebook.
You can see a good shot of it in the pic.

Advice much appreciated,

Carl
neo0x6@gmail.com

 

[Franc Zabkar]

On 15 Dec 2006 13:48:12 -0800, "Carl" <neo0x6@gmail.com> put finger to
keyboard and composed:

Picture here:

http://www.flickr.com/photos/44152487@N00/323329166/

I burned this one up by supplying it -19V (mistakening reversed the
polarity when fixing/resoldering a break in the power cord connector
-doh!)

Perusing the digikey catalog, I assumed it was a toshiba semiconductor
schottkey diode CMS01.

It had an S1 inscribed on it. Even though the dimensions were'nt quite
the same, I gave it a shot.

I've since shorted the 2 CMS01's, so that tisn't it. The CMS01 worked
fine until the laptop drew more current on AC power; it worked fine
allowing the battery to be charged; and on low power app's.

Can anyone help id'ing this component?

Its in parallel with (2) k-ohm resistors on a 19V P15 toshiba notebook.
You can see a good shot of it in the pic.

Do you mean PC1 and PC2? If so, I'm guessing they are capacitors, one
electrolytic, one ceramic. The diode looks like it might just be an
ordinary rectifier. It's job would be to short circuit the input in
the event of a polarity error. However, AFAICS this should take out
the fuse (?) at PF1 (Littelfuse 12Amp?).

Advice much appreciated,

Carl
neo0x6@gmail.com

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

 

[Carl]

Franc,

Thanks for the reply. The 12Amp fuse did survive ok.

What happened on the polarity error was that this diode literally
fried/smoked (I'm glad I had a pic saved of the board). I plucked it
out in little broken pieces.

Can you help with best make/model/specs for a good replacement of this
type rectifier?

The power supply specs are 19V ~ 6.3A

Thanks again for your time,
Carl
neo0x6@gmail.com

http://www.flickr.com/photos/44152487@N00/323329166/


Franc Zabkar wrote:

Do you mean PC1 and PC2? If so, I'm guessing they are capacitors, one
electrolytic, one ceramic. The diode looks like it might just be an
ordinary rectifier. It's job would be to short circuit the input in
the event of a polarity error. However, AFAICS this should take out
the fuse (?) at PF1 (Littelfuse 12Amp?).

Advice much appreciated,

Carl
neo0x6@gmail.com

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

 

[Franc Zabkar]

On 16 Dec 2006 12:18:40 -0800, "Carl" <neo0x6@gmail.com> put finger to
keyboard and composed:

Franc,

Thanks for the reply. The 12Amp fuse did survive ok.

What happened on the polarity error was that this diode literally
fried/smoked (I'm glad I had a pic saved of the board). I plucked it
out in little broken pieces.

Can you help with best make/model/specs for a good replacement of this
type rectifier?

The fuse rating seems odd, so I can't suggest a suitable diode. In any
case you need to find out why your Schottky rectifiers are failing.
Assuming you've corrected your polarity error, then the PIV rating
(30V) of the CMS01 should be more than enough for this circuit, unless
I've misunderstood the workings. Is D1 connected between 19V and
ground?

The power supply specs are 19V ~ 6.3A

Then maybe I'm wrong about the 12A fuse. Also, PC3 appears to be the
main bypass cap, not PC1 or PC2. The latter probably provide HF
bypassing.

Thanks again for your time,
Carl
neo0x6@gmail.com

http://www.flickr.com/photos/44152487@N00/323329166/


Franc Zabkar wrote:

Do you mean PC1 and PC2? If so, I'm guessing they are capacitors, one
electrolytic, one ceramic. The diode looks like it might just be an
ordinary rectifier. It's job would be to short circuit the input in
the event of a polarity error. However, AFAICS this should take out
the fuse (?) at PF1 (Littelfuse 12Amp?).

Advice much appreciated,

Carl
neo0x6@gmail.com

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

 

[Carl]

Franc Zabkar wrote:

On 16 Dec 2006 12:18:40 -0800, "Carl" <neo0x6@gmail.com> put finger to
keyboard and composed:

Franc,

Thanks for the reply. The 12Amp fuse did survive ok.

What happened on the polarity error was that this diode literally
fried/smoked (I'm glad I had a pic saved of the board). I plucked it
out in little broken pieces.

Can you help with best make/model/specs for a good replacement of this
type rectifier?

The fuse rating seems odd, so I can't suggest a suitable diode. In any
case you need to find out why your Schottky rectifiers are failing.
Assuming you've corrected your polarity error, then the PIV rating
(30V) of the CMS01 should be more than enough for this circuit, unless
I've misunderstood the workings. Is D1 connected between 19V and
ground?

PC1, PC2, and the diode all are between +19V and ground.

I am also curious about the purpose of this diode, and if I can power
the laptop safely without it. This would be my assumption if its just
for reverse current protection.

The Schottky's may be failing because of the current? They are rated
at 3A (max).

They may be failing due to heat? Rated at 100deg C. (125 max)

In any case, I am up for a best educated guess on replacement specs.
You mentioned an ordinary rectifier.

Also note the situation in which the Schottkys failed... they worked
fine on powering the battery, and if the notebook was idle, but when
running some intensive apps, pop- it shorted.

The power supply specs are 19V ~ 6.3A

Then maybe I'm wrong about the 12A fuse. Also, PC3 appears to be the
main bypass cap, not PC1 or PC2. The latter probably provide HF
bypassing.

Thanks, this is a bit of a puzzle,

Carl
neo0x6@gmail.com

 

[Franc Zabkar]

On 17 Dec 2006 14:19:29 -0800, "Carl" <neo0x6@gmail.com> put finger to
keyboard and composed:

PC1, PC2, and the diode all are between +19V and ground.

I am also curious about the purpose of this diode, and if I can power
the laptop safely without it. This would be my assumption if its just
for reverse current protection.

The Schottky's may be failing because of the current? They are rated
at 3A (max).

The diode is reverse biased. In this state it should draw no current.
That's the puzzle. You need to sort this out before you can safely
leave it out.

I have no relevant experience with laptops, but in automotive
equipment I have often seen a reverse biased 1A 1N4001 rectifier
across the supply. Such equipment is usually protected by an external
2A fuse or thereabouts. The purpose of the diode is to sacrificially
protect the device in the event of a battery polarity reversal.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.