Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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Old June 17th 04, 01:44 PM
Wayne Peacock
 
Posts: n/a
Default Sony Trinitron brightness problems or old age?

Hi all,

I have a sun GDM-5010PT 21' monitor that I have just fixed the power
supply for. Now the brightness is very dim and I need to up the screen
or sub-brightness. And yes the power supply rails all test OK.

I am aware there are no trimpots and most settings are controlled by
software (DAS from what has been listed in this group). How can I
increase the brightness without the software or would someone have the
protocol for the serial connection?

I am very capable of writing a program and wiring a cable for this if I
know what to write to the monitor. Can a resistor be changed etc?

What is the normal life of a trinitron tube? This monitor was made in
march 1998 and has likely been on for it's life. Could it be on it's
last legs

Thanks
Wayne Peacock






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Old June 17th 04, 01:52 PM
Sam Goldwasser
 
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Default Sony Trinitron brightness problems or old age?

Wayne Peacock writes:

Hi all,

I have a sun GDM-5010PT 21' monitor that I have just fixed the power
supply for. Now the brightness is very dim and I need to up the screen
or sub-brightness. And yes the power supply rails all test OK.

I am aware there are no trimpots and most settings are controlled by
software (DAS from what has been listed in this group). How can I
increase the brightness without the software or would someone have the
protocol for the serial connection?

I am very capable of writing a program and wiring a cable for this if I
know what to write to the monitor. Can a resistor be changed etc?

What is the normal life of a trinitron tube? This monitor was made in
march 1998 and has likely been on for it's life. Could it be on it's
last legs


Brightness half-life of a typical CRT is usually quoted as 15-20K hours.
If it's really been on for 5 years continuous without full power saving
mode implemented, could indeed just be a tired CRT.

Is there not even a screen/G2 pot on the flyback?

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Old June 17th 04, 02:07 PM
Wayne Peacock
 
Posts: n/a
Default Sony Trinitron brightness problems or old age?

Sam Goldwasser wrote:

Wayne Peacock writes:


Hi all,

I have a sun GDM-5010PT 21' monitor that I have just fixed the power
supply for. Now the brightness is very dim and I need to up the screen
or sub-brightness. And yes the power supply rails all test OK.

I am aware there are no trimpots and most settings are controlled by
software (DAS from what has been listed in this group). How can I
increase the brightness without the software or would someone have the
protocol for the serial connection?

I am very capable of writing a program and wiring a cable for this if I
know what to write to the monitor. Can a resistor be changed etc?

What is the normal life of a trinitron tube? This monitor was made in
march 1998 and has likely been on for it's life. Could it be on it's
last legs



Brightness half-life of a typical CRT is usually quoted as 15-20K hours.
If it's really been on for 5 years continuous without full power saving
mode implemented, could indeed just be a tired CRT.


Continuous with power saving. I would assume a normal day in the office!
7 hours per day etc. 'Typical life of CRT' is that the same as a
trinitron? or are trinitrons different.

Is there not even a screen/G2 pot on the flyback?


There are two adjustments on the flyback. But posts in the forums state
them as H & V focus? I have tried adjusting both and they just change
the focus.

Regards
Wayne

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Old June 18th 04, 06:56 AM
LASERandDVDfan
 
Posts: n/a
Default Sony Trinitron brightness problems or old age?

Continuous with power saving. I would assume a normal day in the office!
7 hours per day etc. 'Typical life of CRT' is that the same as a
trinitron? or are trinitrons different.


More or less, they are the same.

Trinitron tubes employ a different electron gun design than conventional
picture tubes as well as employ an aperture grille instead of a shadow mask.

But, Trinitron tubes are still cathode ray tubes. This means that the electron
guns will wear out through use in about the same amount of time as any other
picture tube, give or take a few years. A benefit could be that Trinitrons are
more efficient because of the aperture grille, but that doesn't change the
aforementioned fact.

There are two adjustments on the flyback. But posts in the forums state
them as H & V focus? I have tried adjusting both and they just change
the focus.


Unusual, but there have been stranger things.

There should still be a way to adjust the voltage level going to the picture
tube from the flyback.

However, continuous operation for over five years, even with power saving, may
wear out a picture tube. You may have to consider installing a CRT booster. -
Reinhart
  #5   Report Post  
Old June 18th 04, 03:14 PM
Nigel
 
Posts: n/a
Default Sony Trinitron brightness problems or old age?

Wayne Peacock wrote in
:

Hi all,

I have a sun GDM-5010PT 21' monitor that I have just fixed the power
supply for. Now the brightness is very dim and I need to up the screen
or sub-brightness. And yes the power supply rails all test OK.

I am aware there are no trimpots and most settings are controlled by
software (DAS from what has been listed in this group). How can I
increase the brightness without the software or would someone have the
protocol for the serial connection?

I am very capable of writing a program and wiring a cable for this if I
know what to write to the monitor. Can a resistor be changed etc?

What is the normal life of a trinitron tube? This monitor was made in
march 1998 and has likely been on for it's life. Could it be on it's
last legs


If it's anything like some Sony TVs, you might want to check the value of
the resistors on the tube base before consigning the whole thing to the
scrapheap. Do cold checks on anything above 100K to see if the values have
drifted - I've had plenty that do, causing picture effects not dis-similar
to tube wear. Of course, this doesn't negate the other useful responses
you've had thus far.


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Old June 18th 04, 07:24 PM
Wild Bill
 
Posts: n/a
Default Sony Trinitron brightness problems or old age?

I think the only kludge/last ditch effort I've heard of for getting a little
more life from a dim display was to look for a series resistor in the
filament/heater circuit (and lowering it's value slightly).
This might not be a viable fix on these newer models.

Cheers
WB
................

"Wayne Peacock" wrote in message
...
Hi all,

I have a sun GDM-5010PT 21' monitor that I have just fixed the power
supply for. Now the brightness is very dim and I need to up the screen
or sub-brightness. And yes the power supply rails all test OK.

I am aware there are no trimpots and most settings are controlled by
software (DAS from what has been listed in this group). How can I
increase the brightness without the software or would someone have the
protocol for the serial connection?

I am very capable of writing a program and wiring a cable for this if I
know what to write to the monitor. Can a resistor be changed etc?

What is the normal life of a trinitron tube? This monitor was made in
march 1998 and has likely been on for it's life. Could it be on it's
last legs

Thanks
Wayne Peacock









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