Trinitron Sony tv

kennic · 26-09-2008, 19:44

when i turn on tv it takes a good 2 min for the picture to come on i can hear sound but no picture and the red green light that indicates red when changing channel is flashing on and off untill tv picture is on, tv about 6 years old, what could be the problem

zaeon · 26-09-2008, 20:58

Ageing Electrolytic capacitors in the Power supply is a possibility. As these fail the "Soft start" circuit holds off supplying the HT rail for the CRT's drive circuitry. Have a reliable engineer check the set over. Some early Grundig sets used to exhibit similar faults. One thing Sony got right with the Trinitron CRT sets was that they "under ran" the CRT gun assemblies, having the drive circuitry compensate for the lower gun current to obtain optimal picture results. But, as with many early Japanese product, the Electrolytic capacitors just aren't up to the job and "dry out"....Some Hitachi sets would go into "firework mode" and destroy all the PSU circuitry, silicon, Electros and resistors, all up in smoke and a bunch of "shattered" glass fuses, all needing replacing. Expensive repair that!

Nigel Goodwin · 27-09-2008, 10:08

You need to count how many times the LED flashes, it should flash a certain number of times, stop, and then flash again, this is an error code. You also need to tell me the model number, and I can check the code for you.

However, it sounds very much like AKB failure, this is the auto-greyscale circuitry, and almost certainly caused by the CRT been worn out.

bobzeee · 28-09-2008, 08:36

My Sony KV28 started doing this a year or so ago.

After googling around, I found out it was the CRT failing.
As the guns weaken, they are supplied with more current to balance them out (Auto Kine Bias), but if the current drawn goes over a certain limit, the picture is blanked (IK Blanking).

One workaround, if you are confident poking around inside the set and are aware of the shock hazards, is to locate the 'G2' potentiometer which is on the CRT board, and turn it up a little.
This will give you a few more months at most before it starts blanking again.

Mines is up full now, and it takes 5 mins before the picture appears, with another 10 minutes of blinking on and off.

Time for an upgrade...

26-09-2008, 19:44	#1
kennic Forum Member Join Date: Apr 2007 Posts: 408	Trinitron Sony tv when i turn on tv it takes a good 2 min for the picture to come on i can hear sound but no picture and the red green light that indicates red when changing channel is flashing on and off untill tv picture is on, tv about 6 years old, what could be the problem

26-09-2008, 20:58	#2
zaeon Forum Member Join Date: Jul 2008 Location: County Durham Posts: 311	Ageing Electrolytic capacitors in the Power supply is a possibility. As these fail the "Soft start" circuit holds off supplying the HT rail for the CRT's drive circuitry. Have a reliable engineer check the set over. Some early Grundig sets used to exhibit similar faults. One thing Sony got right with the Trinitron CRT sets was that they "under ran" the CRT gun assemblies, having the drive circuitry compensate for the lower gun current to obtain optimal picture results. But, as with many early Japanese product, the Electrolytic capacitors just aren't up to the job and "dry out"....Some Hitachi sets would go into "firework mode" and destroy all the PSU circuitry, silicon, Electros and resistors, all up in smoke and a bunch of "shattered" glass fuses, all needing replacing. Expensive repair that!

27-09-2008, 10:08	#3
Nigel Goodwin Forum Member Join Date: Apr 2006 Location: North Derbyshire Posts: 41,789	You need to count how many times the LED flashes, it should flash a certain number of times, stop, and then flash again, this is an error code. You also need to tell me the model number, and I can check the code for you. However, it sounds very much like AKB failure, this is the auto-greyscale circuitry, and almost certainly caused by the CRT been worn out.

28-09-2008, 08:36	#4
bobzeee Forum Member Join Date: Jul 2008 Location: Stoneybridge Posts: 122	My Sony KV28 started doing this a year or so ago. After googling around, I found out it was the CRT failing. As the guns weaken, they are supplied with more current to balance them out (Auto Kine Bias), but if the current drawn goes over a certain limit, the picture is blanked (IK Blanking). One workaround, if you are confident poking around inside the set and are aware of the shock hazards, is to locate the 'G2' potentiometer which is on the CRT board, and turn it up a little. This will give you a few more months at most before it starts blanking again. Mines is up full now, and it takes 5 mins before the picture appears, with another 10 minutes of blinking on and off. Time for an upgrade...

DS Forums

Trinitron Sony tv