Prev: TV chassis E90PH96-02
Next: Mitsubishi cs-2710ra vertical problem
From: Andy Cuffe on 11 Aug 2006 16:40
I have a Sony 24" GCM-FW900 monitor with a power supply that keeps
shutting down. It will run for anywhere from 10 seconds to 20 or 30
minutes before shutting down.

All the voltages in the power supply look fine with no ripple. The
power simply shuts off with no change in the output voltages before
shutdown. I've confirmed that the power supply is at fault by
swapping it with a known good power supply.

I've swapped all the major power supply components between the good
and bad one with no change (including the MCZ3001 control IC,
transformer, +220v rectifier, +12v regulator, +220v feedback
reference, optoisolator, output FETs and the timing cap for the
MCZ3001). All the caps test fine for ESR. All resistors measure
fine. Nothing is running hot. It's not at all sensitive to
vibration, or flexing of the board. I've even tried disabling the
over current and over voltage protection with no change.

Does anyone know where I can find a data sheet for the MCZ3001D power
supply control IC? I need to find out exactly what conditions can
make it shut down.
Andy Cuffe

acuffe(a)gmail.com
From: Bob Parker on 12 Aug 2006 01:57
On Fri, 11 Aug 2006 13:40:28 -0700, Andy Cuffe <acuffe(a)gmail.com>
wrote:

>I have a Sony 24" GCM-FW900 monitor with a power supply that keeps
>shutting down. It will run for anywhere from 10 seconds to 20 or 30
>minutes before shutting down.
>
>All the voltages in the power supply look fine with no ripple. The
>power simply shuts off with no change in the output voltages before
>shutdown. I've confirmed that the power supply is at fault by
>swapping it with a known good power supply.
>
>I've swapped all the major power supply components between the good
>and bad one with no change (including the MCZ3001 control IC,
>transformer, +220v rectifier, +12v regulator, +220v feedback
>reference, optoisolator, output FETs and the timing cap for the
>MCZ3001). All the caps test fine for ESR. All resistors measure
>fine. Nothing is running hot. It's not at all sensitive to
>vibration, or flexing of the board. I've even tried disabling the
>over current and over voltage protection with no change.
>
>Does anyone know where I can find a data sheet for the MCZ3001D power
>supply control IC? I need to find out exactly what conditions can
>make it shut down.
>Andy Cuffe
>
>acuffe(a)gmail.com

Hi Andy,
All I was able to find was a schematic of a Sony
KV-27FV300/29FV300/32FV300/36FV300 power supply with this chip in the
middle, and an internal block diagram of the chip.
If either will help (probably not), I'll send 'em to you.

Bob


From: Electric dabbler on 16 Aug 2006 18:57

"Bob Parker" <bobp.deletethis(a)bluebottle.com> wrote in message
news:nbrqd29pp3o8u690kbl7er4ph25hh41qfi(a)4ax.com...
> On Fri, 11 Aug 2006 13:40:28 -0700, Andy Cuffe <acuffe(a)gmail.com>
> wrote:
>
>>I have a Sony 24" GCM-FW900 monitor with a power supply that keeps
>>shutting down. It will run for anywhere from 10 seconds to 20 or 30
>>minutes before shutting down.
>>
>>All the voltages in the power supply look fine with no ripple. The
>>power simply shuts off with no change in the output voltages before
>>shutdown. I've confirmed that the power supply is at fault by
>>swapping it with a known good power supply.
>>
>>I've swapped all the major power supply components between the good
>>and bad one with no change (including the MCZ3001 control IC,
>>transformer, +220v rectifier, +12v regulator, +220v feedback
>>reference, optoisolator, output FETs and the timing cap for the
>>MCZ3001). All the caps test fine for ESR. All resistors measure
>>fine. Nothing is running hot. It's not at all sensitive to
>>vibration, or flexing of the board. I've even tried disabling the
>>over current and over voltage protection with no change.
>>
>>Does anyone know where I can find a data sheet for the MCZ3001D power
>>supply control IC? I need to find out exactly what conditions can
>>make it shut down.
>>Andy Cuffe
>>
>>acuffe(a)gmail.com
>
> Hi Andy,
> All I was able to find was a schematic of a Sony
> KV-27FV300/29FV300/32FV300/36FV300 power supply with this chip in the
> middle, and an internal block diagram of the chip.
> If either will help (probably not), I'll send 'em to you.
>
> Bob
>
>
Hi Andy,

The manufacturer is Shindengen
http://www.shindengen.co.uk/index.asp?page=semiconductors

Sadly no data sheet, it is very commonly used in Sony CRT TV's and I've even
seen it used in a couple of LCD models.

As far as I remember it has three protection mechanisms:

Pin 1 is used for under voltage lockout (ac line voltage)
Pin 8 (VCC) is monitored for excessive voltage. >18V rings a bell but I
wouldn't swear to it
Pin 9 (OCP) monitors current accross the sense resistor(s) on the primary
side.I've never had much luck moitoring Pin 9 as the voltage waveform here
is tiny.


Good luck fixing it.

Philip


From: Andy Cuffe on 17 Aug 2006 16:33
On Wed, 16 Aug 2006 23:57:58 +0100, "Electric dabbler"
<no.spam(a)microsoft.com> wrote:

>> Hi Andy,
>> All I was able to find was a schematic of a Sony
>> KV-27FV300/29FV300/32FV300/36FV300 power supply with this chip in the
>> middle, and an internal block diagram of the chip.
>> If either will help (probably not), I'll send 'em to you.
>>
>> Bob

Thanks for the tip. I found some information a Sony training manual
for a TV using the same power supply IC. It gave some good pointers,
but nothing that helped in this case.


>Hi Andy,
>
>The manufacturer is Shindengen
>http://www.shindengen.co.uk/index.asp?page=semiconductors
>
>Sadly no data sheet, it is very commonly used in Sony CRT TV's and I've even
>seen it used in a couple of LCD models.
>
>As far as I remember it has three protection mechanisms:
>
>Pin 1 is used for under voltage lockout (ac line voltage)
>Pin 8 (VCC) is monitored for excessive voltage. >18V rings a bell but I
>wouldn't swear to it
>Pin 9 (OCP) monitors current accross the sense resistor(s) on the primary
>side.I've never had much luck moitoring Pin 9 as the voltage waveform here
>is tiny.
>
>
>Good luck fixing it.
>
>Philip
>
All those voltages were fine right up to and even shortly after shut
down. I ties the OCP pin to ground, so that should have completely
disabled OCP.

Next I replaced the two 1kV 330pF caps going from D to S on the output
FETs (C641,643). So far the power supply has been running fine, but
only time will tell. The same caps worked fine in the other power
supply, but the stress of de-soldering could have temporarily fixed an
intermittent short, or open in one of the caps.

I'm almost out of parts to replace in this thing! I'm just glad I had
a working supply to swap parts with.

Interestingly, the bad supply was manufactured using lead free solder
and the good one uses regular. The first thing I did was to re-solder
pretty much everything in the power supply (including the caps in
question).
Andy Cuffe

acuffe(a)gmail.com
From: Electric dabbler on 18 Aug 2006 14:05

"Andy Cuffe" <acuffe(a)gmail.com> wrote in message
news:e3k9e2hqehfdl9dphkdpfcq6ppjp214075(a)4ax.com...
> On Wed, 16 Aug 2006 23:57:58 +0100, "Electric dabbler"
> <no.spam(a)microsoft.com> wrote:
>
>>> Hi Andy,
>>> All I was able to find was a schematic of a Sony
>>> KV-27FV300/29FV300/32FV300/36FV300 power supply with this chip in the
>>> middle, and an internal block diagram of the chip.
>>> If either will help (probably not), I'll send 'em to you.
>>>
>>> Bob
>
> Thanks for the tip. I found some information a Sony training manual
> for a TV using the same power supply IC. It gave some good pointers,
> but nothing that helped in this case.
>
>
>>Hi Andy,
>>
>>The manufacturer is Shindengen
>>http://www.shindengen.co.uk/index.asp?page=semiconductors
>>
>>Sadly no data sheet, it is very commonly used in Sony CRT TV's and I've
>>even
>>seen it used in a couple of LCD models.
>>
>>As far as I remember it has three protection mechanisms:
>>
>>Pin 1 is used for under voltage lockout (ac line voltage)
>>Pin 8 (VCC) is monitored for excessive voltage. >18V rings a bell but I
>>wouldn't swear to it
>>Pin 9 (OCP) monitors current accross the sense resistor(s) on the primary
>>side.I've never had much luck moitoring Pin 9 as the voltage waveform here
>>is tiny.
>>
>>
>>Good luck fixing it.
>>
>>Philip
>>
> All those voltages were fine right up to and even shortly after shut
> down. I ties the OCP pin to ground, so that should have completely
> disabled OCP.
>
> Next I replaced the two 1kV 330pF caps going from D to S on the output
> FETs (C641,643). So far the power supply has been running fine, but
> only time will tell. The same caps worked fine in the other power
> supply, but the stress of de-soldering could have temporarily fixed an
> intermittent short, or open in one of the caps.
>
> I'm almost out of parts to replace in this thing! I'm just glad I had
> a working supply to swap parts with.
>
> Interestingly, the bad supply was manufactured using lead free solder
> and the good one uses regular. The first thing I did was to re-solder
> pretty much everything in the power supply (including the caps in
> question).
> Andy Cuffe
>

Hope you found it with the caps. I've had that thing happen to me, very
annoying when the faulty component fixes itself.


Philip


 | 
Pages: 1
Prev: TV chassis E90PH96-02
Next: Mitsubishi cs-2710ra vertical problem