Advice with Toshiba TN55V71 picture shrinking?

[jeffrey776]

I have a Toshiba TN55V71 and the picture is pulling in / shrinking? Leaving a 3 to 4 inch band of black around the outer edge this is intermittent and tends to come and go maybe 4 times in a 2 hour period.
I have already replaced the convergence amps this was approx. 3 months ago.
Any advice would be appreciated.
Thank You
I am a gaming machine technician and this falls outside my regular focus of expertise.
Again thanks all info welcome.

 

[jeffrey776]

More information: I have been told that when switching channels the screen returns to full scale then reverts back to what I described above. Also I'm told that the sides vertical are more of a pincushion shape. Does any of this help?

 

[Toe Cutter]

Its not clear to me what type of display technology this Toshiba uses. CRT? From your description I would guess bad solder joints. If CRT, then look around the horizontal and vertical deflection circuits.

 

[tunedwolf]

Probably a dodgy power supply, the STK modules are famous for trouble. Just be careful that the supply doesn't pop a lamp. Check the 160V rail for fluctuations etc. After thinking about it, you might be best to get an experienced tech to sort this one for you, mistakes on rear projection sets are usually very costly.

rgds

 

[jeffrey776]

Probably a dodgy power supply, the STK modules are famous for trouble. Just be careful that the supply doesn't pop a lamp. Check the 160V rail for fluctuations etc. After thinking about it, you might be best to get an experienced tech to sort this one for you, mistakes on rear projection sets are usually very costly.

rgds

Thanks, It's just as the economy is now, I don't want to run out and buy a new hi-def television. I was hoping to get another year out of this one. I'll check the 160v rail and see how that goes. Much thanks to those of you who responded to my question.