Adjusting monitor focus: Sun/Sony GDM-5010 PT
 

Most Trinitron screens I've worked with have had the focus controls
behind two obvious holes in the cabinet, towards the back on the left
side. However, this screen doesn't seem to have those.

Can anyone point me in the right direction?

Please post here or email to steve_wechsler(at)yahoo.com

Thanks,

Steve

"Steve" wrote in message
oups.com...
Most Trinitron screens I've worked with have had the focus controls
behind two obvious holes in the cabinet, towards the back on the left
side. However, this screen doesn't seem to have those.

Can anyone point me in the right direction?

Please post here or email to steve_wechsler(at)yahoo.com

Thanks,

Steve


Take the cover off, they're still there on most monitors.

Open the back cover, and look on the flyback transformer. There may be two
or three pots. One will most likely be the beam focus, and the other(s) will
be the focus adjustment.

In some sets, the focus control is on the CRT circuit board.

Before touching anything, read carefully what the adjustment does. Use only
a plastic or Teflon tip (non conducting) tool to adjust these pots. Using
the fingers can be risky, if you are not used to this type of work. If you
use a conductive type tool to do the adjustment, and you slip, there is a
very good possibility to do circuit damage, as well as possibly get hurt.

If the monitor or TV sets requires the focus to be touched up, this is a
sign that either the CRT is going weak, or that there is something failing
in the high voltage section.

--

JANA
_____


"Steve" wrote in message
oups.com...
Most Trinitron screens I've worked with have had the focus controls
behind two obvious holes in the cabinet, towards the back on the left
side. However, this screen doesn't seem to have those.

Can anyone point me in the right direction?

Please post here or email to steve_wechsler(at)yahoo.com

Thanks,

Steve

Most newer Sony's use an external Digital Alignment System (DAS)
connected to a computer to make these adjustments. (Expensive). You
might try and trace out the circuit grom the screen (G2) pin on the CRT
neck board. There should be a large value resistor in the circuit.
Changing the value of this resistor will often change the screen
voltage and brightness. You have to experiment a little to find a good
value. I use an resistor box and start at the highest value and then go
down until I find the best brightness. Then I solder a fixed resistor
in the circuit.
Hope this helps....
John

wrote in message
oups.com...
Most newer Sony's use an external Digital Alignment System (DAS)
connected to a computer to make these adjustments. (Expensive). You
might try and trace out the circuit grom the screen (G2) pin on the CRT
neck board. There should be a large value resistor in the circuit.
Changing the value of this resistor will often change the screen
voltage and brightness. You have to experiment a little to find a good
value. I use an resistor box and start at the highest value and then go
down until I find the best brightness. Then I solder a fixed resistor
in the circuit.
Hope this helps....
John


You'd think someone would have hacked together a hobby version of the DAS,
how hard could it be to do it with a cheap microcontroller? Of course you'd
have to find access to a real DAS unit/software to analyze the protocol it
uses.

In article .com, wrote:
Most newer Sony's use an external Digital Alignment System (DAS)
connected to a computer to make these adjustments. (Expensive). You
might try and trace out the circuit grom the screen (G2) pin on the CRT
neck board. There should be a large value resistor in the circuit.
Changing the value of this resistor will often change the screen
voltage and brightness. You have to experiment a little to find a good
value. I use an resistor box and start at the highest value and then go
down until I find the best brightness. Then I solder a fixed resistor
in the circuit.
Hope this helps....
John

Focus is adjusted using the traditional pots. Here's the extract from
the n31s_fcs.stp file that drives DAS for the GDM-5010:

BEGIN
SCREEN "FOCUS ADJUSTMENT" 15 1 65 22
message full_screen "Perform the focus adjustment:\
a) adjust the [F2] focus pot for best vertical focus.\
b) adjust the [F1] focus pot for best horizontal overall focus.\
c) repeat [F1] and [F2] as there is some interaction."
BUTTON CANCEL
BUTTON OK
END

G2, however, is adjusted using DAS control.

Mike.