unknown IC on Westinghouse LCD power supply board

R

Rick

Guest
This is re: Westinghouse LCM-17v8 LCD monitor.

Found several reports of maybe 2 or 4 capacitors popping on the power
supply boards for this monitor. The one I have popped 6 capacitors and
blew the fuse. Ok, that's all readily replaceable.

What concerns me is the PCB is darkened around 4 IC's on the board as
well - possibly thermal damage. The IC's are a standard 8 pin DIP
package, 3 of them marked P605 (over) BD6L2P, 1 marked P605 (over)
BD6L2B The trademark on the IC's is a script letter "A" - obviously not
AMD.

Google can't find a thing on this IC part number. I'm stumped on the
manufacturer. Any idea what that these IC's are? I don't want to bother
replacing the caps and fuse on the board until I can figure out what
these IC's do. I sure don't have a replacement option for them at this
point. :cool: The power supply board was manufactured by Delta Electronics.

Rick
 
On Sat, 07 Mar 2009 20:24:17 -0500, Rick <rickajho@rcn.com> put finger
to keyboard and composed:

The IC's are a standard 8 pin DIP
package, 3 of them marked P605 (over) BD6L2P, 1 marked P605 (over)
BD6L2B The trademark on the IC's is a script letter "A" - obviously not
AMD.
Click to expand...
The logo belongs to Alpha & Omega Semiconductor, Inc.

The part number is AOP605. It is an N-Channel Complementary
Enhancement Mode Field Effect Transistor, 30V, 7.5A.

BD6L2P and BD6L2B are actually date/batch codes.

Here is the datasheet:
http://www.aosmd.com/pdfs/datasheet/AOP605.pdf
http://www.datasheetarchive.com/pdf-datasheets/Datasheets-28/DSA-557650.pdf

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.
 
On Sun, 08 Mar 2009 13:42:54 +1100, Franc Zabkar
<fzabkar@iinternode.on.net> put finger to keyboard and composed:

On Sat, 07 Mar 2009 20:24:17 -0500, Rick <rickajho@rcn.com> put finger
to keyboard and composed:

The IC's are a standard 8 pin DIP
package, 3 of them marked P605 (over) BD6L2P, 1 marked P605 (over)
BD6L2B The trademark on the IC's is a script letter "A" - obviously not
AMD.

The logo belongs to Alpha & Omega Semiconductor, Inc.

The part number is AOP605. It is an N-Channel Complementary
Enhancement Mode Field Effect Transistor, 30V, 7.5A.
Click to expand...
Sorry, it's a dual N-channel and P-channel MOSFET.

Available from Digikey for $0.87:
http://parts.digikey.com/1/parts/1502429-mosfet-n-p-ch-compl-30v-8-pdip-aop605.html

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

On Sun, 08 Mar 2009 13:42:54 +1100, Franc Zabkar
fzabkar@iinternode.on.net> put finger to keyboard and composed:


On Sat, 07 Mar 2009 20:24:17 -0500, Rick <rickajho@rcn.com> put finger
to keyboard and composed:


The IC's are a standard 8 pin DIP
package, 3 of them marked P605 (over) BD6L2P, 1 marked P605 (over)
BD6L2B The trademark on the IC's is a script letter "A" - obviously not
AMD.

The logo belongs to Alpha & Omega Semiconductor, Inc.

The part number is AOP605. It is an N-Channel Complementary
Enhancement Mode Field Effect Transistor, 30V, 7.5A.


Sorry, it's a dual N-channel and P-channel MOSFET.

Available from Digikey for $0.87:
http://parts.digikey.com/1/parts/1502429-mosfet-n-p-ch-compl-30v-8-pdip-aop605.html

- Franc Zabkar
Click to expand...
Thanks Frank! I was at Digikey - how did I miss that?

It looks like a fairly robust part and I'd expect to see a certain
amount of thermal discoloration around those IC's on the circuit board.
The owner swears the damage occurred during a single power on attempt -
says she got nothing at all when she turned the monitor on after it had
been powered off for about a week. No smoke, didn't hear anything.

Unlikely the MOFSET's are damaged since the capacitors - and the fuse -
on the power supply board blew? Any thoughts? (Damned cheap electrolytic
capacitors...)

Rick
 
On Sun, 08 Mar 2009 07:39:59 -0500, Rick <rickajho@rcn.com> put finger
to keyboard and composed:

Unlikely the MOFSET's are damaged since the capacitors - and the fuse -
on the power supply board blew? Any thoughts? (Damned cheap electrolytic
capacitors...)

Rick
Click to expand...
Since the fuse blew, and assuming it wasn't just "tired", I'd be
looking for shorted components. That's how MOSFETs usually fail, IME.

Having said that, I've seen many posts where replacing capacitors and
picofuses was all that was required.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.
 
On Mar 8, 8:39 am, Rick <ricka...@rcn.com> wrote:
Franc Zabkar wrote:
On Sun, 08 Mar 2009 13:42:54 +1100, Franc Zabkar
fzab...@iinternode.on.net> put finger to keyboard and composed:

On Sat, 07 Mar 2009 20:24:17 -0500, Rick <ricka...@rcn.com> put finger
to keyboard and composed:

The IC's are a standard 8 pin DIP
package, 3 of them marked P605 (over) BD6L2P, 1 marked P605 (over)
BD6L2B  The trademark on the IC's is a script letter "A" - obviously not
AMD.

The logo belongs to Alpha & Omega Semiconductor, Inc.

The part number is AOP605. It is an N-Channel Complementary
Enhancement Mode Field Effect Transistor, 30V, 7.5A.

Sorry, it's a dual N-channel and P-channel MOSFET.

Available from Digikey for $0.87:
http://parts.digikey.com/1/parts/1502429-mosfet-n-p-ch-compl-30v-8-pd...

- Franc Zabkar

Thanks Frank! I was at Digikey - how did I miss that?

It looks like a fairly robust part and I'd expect to see a certain
amount of thermal discoloration around those IC's on the circuit board.
The owner swears the damage occurred during a single power on attempt -
says she got nothing at all when she turned the monitor on after it had
been powered off for about a week. No smoke, didn't hear anything.

Unlikely the MOFSET's are damaged since the capacitors - and the fuse -
on the power supply board blew? Any thoughts? (Damned cheap electrolytic
capacitors...)

Rick
Click to expand...
You know the caps need replaced, they were lossy and possibly one
shorted, pull them all off and check for shorts. Also check the
transistors for shorts, if the caps were bad enough it could have
blown one but no need to assume one way or the other, if they are you
will find it with a multimeter. If it's a matter of ordering all the
parts in a timely fashion you could go ahead and order those too, then
wait to see if you need to replace any. Since they were getting quite
hot, inspect the traces to them in case those started to delaminate
from the board.
 
On Sun, 08 Mar 2009 07:39:59 -0500, Rick <rickajho@rcn.com> wrote:

Franc Zabkar wrote:

On Sun, 08 Mar 2009 13:42:54 +1100, Franc Zabkar
fzabkar@iinternode.on.net> put finger to keyboard and composed:


On Sat, 07 Mar 2009 20:24:17 -0500, Rick <rickajho@rcn.com> put finger
to keyboard and composed:


The IC's are a standard 8 pin DIP
package, 3 of them marked P605 (over) BD6L2P, 1 marked P605 (over)
BD6L2B The trademark on the IC's is a script letter "A" - obviously not
AMD.

The logo belongs to Alpha & Omega Semiconductor, Inc.

The part number is AOP605. It is an N-Channel Complementary
Enhancement Mode Field Effect Transistor, 30V, 7.5A.


Sorry, it's a dual N-channel and P-channel MOSFET.

Available from Digikey for $0.87:
http://parts.digikey.com/1/parts/1502429-mosfet-n-p-ch-compl-30v-8-pdip-aop605.html

- Franc Zabkar

Thanks Frank! I was at Digikey - how did I miss that?

It looks like a fairly robust part and I'd expect to see a certain
amount of thermal discoloration around those IC's on the circuit board.
The owner swears the damage occurred during a single power on attempt -
says she got nothing at all when she turned the monitor on after it had
been powered off for about a week. No smoke, didn't hear anything.

Unlikely the MOFSET's are damaged since the capacitors - and the fuse -
on the power supply board blew? Any thoughts? (Damned cheap electrolytic
capacitors...)

Rick
This is a common problem with these monitors. Cheap capacitors, poor
Click to expand...
ventilation, and suddenly you have a failure. The ususal chain of
events is the caps degrade, resulting in high ripple. Then things
deteriorate from there. I've had many that require only cap
replacement. In one case, the only other problem was a blown fuse in
the inverter. Common symptoms include turning on, then off again;
backlight turns off, then on, backlight won't turn on, fuse blown,
etc.

There is a lot of information on the problem at
http://www.badcaps.net/forum/forumdisplay.php?f=28

Recommendation is to replace ALL electrolytic caps in the power supply
and inverter with Panasonic FC, Nichicon PM or equivalent. You
already mentioned Digi-Key. I was thrilled recently to discover they
no longer have a handling charge for small orders. The caps to redo
two monitors cost less than $10 - delivered.

PlainBill
 
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