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-   -   Sony F500R CRT (https://www.diybanter.com/electronics-repair/265515-sony-f500r-crt.html)

No Name November 24th 08 02:54 PM

Sony F500R CRT
 
A few months ago I located a "new old stock" Sony F500R CRT.
It was bought as a spare for a corporation but had never been used
since its manufacture date of November 1999.

When I first started using the set, the picture was absolutely perfect,
until my nephew decided to see what the "auto restoration" feature
was for on the monitor. Zip, zap, the picture flung around and then
resettled back down. No harm, or so I thought.

Ever since, when I power on the monitor, the brightness is overdriven
and I cannot get a pure black level. If I set the brightness to zero it's
pretty close. After about ten minutes the brightness decreases rather
rapidly, and I have to manually adjust it back upwards to achieve a
proper black level, and it stays fine until it's powered off again, and
I have to repeat the same cycle all over again.

My two questions are,

1. What is the likely cause of this problem? Bad caps, or is there
an internal way to reset whatever the "auto restoration" function did?

2. If the likely problem is bad components, is anyone reading this in
the Bay Area of California, and would you like to make some money
repairing it for me? I can't say money is no object but I'm willing to
pay several hundred in labor costs to get the monitor thoroughly
tested and repaired correctly.

Thanks.





Jerry G. November 29th 08 09:06 PM

Sony F500R CRT
 

I don't know what unit this CRT goes with, but I can offer a possible
suggestion.

Look on the high voltage transformer assembly, or on the HV
multiplier, or on one of the CRT drive circuit boards. Look for an
adjustment called CRT bias, or Screen, or G2. Mark the position of
the pot so that you can move it back. Try the adjustment.


Jerry G.


On Nov 24, 9:54*am, wrote:
A few months ago I located a "new old stock" Sony F500R CRT.
It was bought as a spare for a corporation but had never been used
since its manufacture date of November 1999.

When I first started using the set, the picture was absolutely perfect,
until my nephew decided to see what the "auto restoration" feature
was for on the monitor. *Zip, zap, the picture flung around and then
resettled back down. *No harm, or so I thought.

Ever since, when I power on the monitor, the brightness is overdriven
and I cannot get a pure black level. *If I set the brightness to zero it's
pretty close. *After about ten minutes the brightness decreases rather
rapidly, and I have to manually adjust it back upwards to achieve a
proper black level, and it stays fine until it's powered off again, and
I have to repeat the same cycle all over again.

My two questions are,

1. What is the likely cause of this problem? *Bad caps, or is there
an internal way to reset whatever the "auto restoration" function did?

2. If the likely problem is bad components, is anyone reading this in
the Bay Area of California, and would you like to make some money
repairing it for me? *I can't say money is no object but I'm willing to
pay several hundred in labor costs to get the monitor thoroughly
tested and repaired correctly.

Thanks.



Powermac November 30th 08 03:52 AM

Sony F500R CRT
 
On Nov 29, 4:06*pm, "Jerry G." wrote:
I don't know what unit this CRT goes with, but I can offer a possible
suggestion.

Look on the high voltage transformer assembly, or on the HV
multiplier, or on one of the CRT drive circuit boards. Look for an
adjustment called CRT bias, or Screen, or G2. *Mark the position of
the pot so that you can move it back. Try the adjustment.

Jerry G.

On Nov 24, 9:54*am, wrote:



A few months ago I located a "new old stock" Sony F500R CRT.
It was bought as a spare for a corporation but had never been used
since its manufacture date of November 1999.


When I first started using the set, the picture was absolutely perfect,
until my nephew decided to see what the "auto restoration" feature
was for on the monitor. *Zip, zap, the picture flung around and then
resettled back down. *No harm, or so I thought.


Ever since, when I power on the monitor, the brightness is overdriven
and I cannot get a pure black level. *If I set the brightness to zero it's
pretty close. *After about ten minutes the brightness decreases rather
rapidly, and I have to manually adjust it back upwards to achieve a
proper black level, and it stays fine until it's powered off again, and
I have to repeat the same cycle all over again.


My two questions are,


1. What is the likely cause of this problem? *Bad caps, or is there
an internal way to reset whatever the "auto restoration" function did?


2. If the likely problem is bad components, is anyone reading this in
the Bay Area of California, and would you like to make some money
repairing it for me? *I can't say money is no object but I'm willing to
pay several hundred in labor costs to get the monitor thoroughly
tested and repaired correctly.


Thanks.- Hide quoted text -


- Show quoted text -


Hit the reset button on the monitor (after it has warmed up for 30
minutes), then get into the menu and do a auto restore.
I think the restore function needs to have the contrast and brightness
at a default setting to work sometimes. I had the brightness problem
on my 420GS and doing the above steps fixed it.



Andy Cuffe December 1st 08 03:55 PM

Sony F500R CRT
 
On Mon, 24 Nov 2008 06:54:17 -0800, wrote:


Ever since, when I power on the monitor, the brightness is overdriven
and I cannot get a pure black level. If I set the brightness to zero it's
pretty close. After about ten minutes the brightness decreases rather
rapidly, and I have to manually adjust it back upwards to achieve a
proper black level, and it stays fine until it's powered off again, and
I have to repeat the same cycle all over again.


If anything, the auto restore should fix any brightness problems, not
cause them.

This behavior is normal for Sony monitors. Every single one I've seen
starts out overly bright, but settles down after about 10 minutes.
When fully warmed up, the brightness should need to be set to around
30 if everything is working correctly. The easiest way to set the
brightness is to open a full screen DOS box, and adjust it so that the
raster lines in the black area are just slightly visible in a dark
room.
Andy Cuffe



No Name December 1st 08 08:59 PM

Sony F500R CRT
 
"Andy Cuffe" wrote in message ...
On Mon, 24 Nov 2008 06:54:17 -0800, wrote:


Ever since, when I power on the monitor, the brightness is overdriven
and I cannot get a pure black level. If I set the brightness to zero it's
pretty close. After about ten minutes the brightness decreases rather
rapidly, and I have to manually adjust it back upwards to achieve a
proper black level, and it stays fine until it's powered off again, and
I have to repeat the same cycle all over again.


If anything, the auto restore should fix any brightness problems, not
cause them.

This behavior is normal for Sony monitors. Every single one I've seen
starts out overly bright, but settles down after about 10 minutes.
When fully warmed up, the brightness should need to be set to around
30 if everything is working correctly. The easiest way to set the
brightness is to open a full screen DOS box, and adjust it so that the
raster lines in the black area are just slightly visible in a dark
room.
Andy Cuffe



What's confusing is, my monitor did not behave this way until my nephew
did the image restoration function. The monitor never required brightness
adjustment.

I tried the reset button/image restore sequence suggested by another
poster, it didn't help.



Andy Cuffe December 1st 08 09:58 PM

Sony F500R CRT
 
On Mon, 1 Dec 2008 12:59:15 -0800, wrote:


What's confusing is, my monitor did not behave this way until my nephew
did the image restoration function. The monitor never required brightness
adjustment.

I tried the reset button/image restore sequence suggested by another
poster, it didn't help.


It's possible that the brightness was low enough that it wasn't
noticeable even when it was first turned on. I'm willing to bet that
the brightness level ended up being too low once it warmed up. Many
people have the brightness set too low, and don't notice the missing
shadow detail, or even prefer the high contrast look. Now that it's
correctly adjusted, it's too bright when it's cold.

I've worked with dozens of these monitors, and every single one has
been noticeably too bright when first turned on. I've seen this
problem mentioned on discussion forums too. As long as you can get
the correct brightness after warm up, the monitor is working properly.
Andy Cuffe




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