Old Sony CRT TV service mode ?

Thread Starter

ranatungawk

Joined Oct 30, 2008
172
This is 1990 - 91 Sony KV 2192M3 CRT TV , Has this a service mode ?
How do we know a TV has a service mode ?
 
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Yaakov

Joined Jan 27, 2019
3,755
Thanks. I got this. But there were no any information about a service mode. Have you any idea ?
Older TVs were serviced using bench top signal generators, they didn't have any internal diagnostics. It is exceedingly unlikely that, in the absence of any information in the service manual, this one would be an exception.
 

Thread Starter

ranatungawk

Joined Oct 30, 2008
172
B
Older TVs were serviced using bench top signal generators, they didn't have any internal diagnostics. It is exceedingly unlikely that, in the absence of any information in the service manual, this one would be an exception.
As far as i can remember, TV made after 93 had got a service menu and there were a remote-controller Key-combination to access it.
 

Yaakov

Joined Jan 27, 2019
3,755
Before the advent of reasonably powerful microprocessors in TVs, adding an internal diagnostics capability meant adding more hardware, not just software. It wouldn't be cost effective.

The service manual would certainly provide any information on such a feature, since that's what it is for.
 

Ramussons

Joined May 3, 2013
1,100
This is 1990 - 91 Sony KV 2192M3 CRT TV , Has this a service mode ?
How do we know a TV has a service mode ?
Not likely.
AFAIK, the Service mode in a TV is used to adjust the Scan Widths and Hor / Ver shift . besides other parameters of Intensity, White Balance....
This is required in a LCD / LED tv. In a CRT, these parameters are set by physically adjusting the Deflection coils and some Presets.
 

ronsimpson

Joined Oct 7, 2019
1,659
Has this a service mode ?
I don't remember that set but.....I did design work for Sony over years and some sets have a three pin connector hidden that talks "TTL level rs-232". (TX, gnd, RX) We used a old pc to talk to the micro computer. There never was a service mode. You would need to find the serial connection to the micro.
Your TV must be new enough to have a micro. !!
You would need to have the program to talk to the micro. or you need to know the commands.
I think the TVs talked a different language than the monitors.
My bad memory ..... there are one & two letter commands followed by a number. Unless you under stand V. Size, V. C-lin, V. S-lin, V-center etc you are just going to mess things up worse. Some of the big monitors had a 16 long V. linearity table. Maybe the table was 32 long. It has been too many years.
 

Thread Starter

ranatungawk

Joined Oct 30, 2008
172
Not likely.
AFAIK, the Service mode in a TV is used to adjust the Scan Widths and Hor / Ver shift . besides other parameters of Intensity, White Balance....
This is required in a LCD / LED tv. In a CRT, these parameters are set by physically adjusting the Deflection coils and some Presets.
I Need to fix the following screen shape issue.

1625716120001.png
 
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Thread Starter

ranatungawk

Joined Oct 30, 2008
172
I don't remember that set but.....I did design work for Sony over years and some sets have a three pin connector hidden that talks "TTL level rs-232". (TX, gnd, RX) We used a old pc to talk to the micro computer. There never was a service mode. You would need to find the serial connection to the micro.
Your TV must be new enough to have a micro. !!
You would need to have the program to talk to the micro. or you need to know the commands.
I think the TVs talked a different language than the monitors.
My bad memory ..... there are one & two letter commands followed by a number. Unless you under stand V. Size, V. C-lin, V. S-lin, V-center etc you are just going to mess things up worse. Some of the big monitors had a 16 long V. linearity table. Maybe the table was 32 long. It has been too many years.
Can i change the shape of the screen with the above presets ? (Please see the above pic)
 

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Yaakov

Joined Jan 27, 2019
3,755
There is probably a variable resistor that adjusts keystone somewhere on the PCB. They usually grouped them to make it easier but I couldn’t see most of them (according to the parts list) on the boards in that PDF due to poor quality.
 

Thread Starter

ranatungawk

Joined Oct 30, 2008
172
There is probably a variable resistor that adjusts keystone somewhere on the PCB. They usually grouped them to make it easier but I couldn’t see most of them (according to the parts list) on the boards in that PDF due to poor quality.
can this also comes due to an issue of the Yoke coil ?
 
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