Toshiba cn36h97 TV

I picked up this tv for a song at a local thrift store. Worked well till I got a horizontal white line on the screen. Replaced the vertical drive IC and a number of caps. Then I had a full screen with a green raster with horizontal lines. I checked the voltages at the crt drive transistors at the collector to ground, and green was almost negligible. I swapped it with blue and got the same result in blue. I replaced all three transistors and now finally get a picture, minus green. I went into the system checks and have red, blue, and black where green should be. I noticed afterwards the green transistor was fairly warm but the other two were cool. Looks to me like a short caused a cascading into the vertical drive. Not sure where to go from here and hoping it is not the crt. Anybody have any suggestions?

Hello Handiman55, welcome to the forum I am happy you joined us.

The problem seems to be the warm green transistor? (cause you write you now have a picture)

Thanks for reply. I have a warm green power transistoron the crt board , as compared to the red and blue. There is also evidence of some browning of the circuit board around the green one. And no green in the picture. But I do now have a picture!

You could not replace the green power transistor? (I think I'm missing something, because you would probably have figured this out yourself as well)

I replaced the green transistor, as well as the blue and red. Prior to the changeout I checked the collector voltages and the green was almost 0. The other two were ok. After the change all three read the same with the crt board connected to the tube, and off, powered up. I then, just to be sure, changed the green again with the same results. I have the service manual so I can talk specifics if needed as far as part numbers and locations. The transistor in question is Q903.

this sounds like this tv might be a real problem,discription sound like to me a crt problem i see it all day long in hotel motel hospital sets rca ctc203s.if you have lightgreen schreen with white retrace line about one inch apart at a angle from upper right down to your left you have a shorted heater to cathode short.this tv also will do it in i have seen red purple dark blue its all picture tube problems.this is the reason it was in a second hand store.

Post edited by: hobbist, at: 2008/04/17 18:43

Thanks, you hit the nail on the head. I had this screen prior to changing the green transistor. I appreciate your explanation as to why, or what, went wrong. Now to dispose of this 200 pound monster! Again, thanks, I will not put any more effort into this one. Too bad it was a really good picture and a large screen. Miss it. Jim

been doing this kind of work in customer electronics and own a tv station for 31 yrs.plus appliances.also a transmission rebuilder and machinist for 12yrs.
presently employed in bio medical electronics senior chief engineer.

Post edited by: hobbist, at: 2008/04/17 21:25

Run a business called Anything Mechanical here. Fix most anything on the island. Done my bit with aircraft manufacture and now on my own. Now contemplating building a radial RC engine. Do a bit of machining etc too. Jim

i was just wondering where the island.i in north carolina 25 miles east of capital of nc.raleigh.

so you both are living real close to each other?

Other coast! Whidbey Island in Washington State

ten four i though you were from long island ny.i orginally from binghamton ny middle of the state just off us81 100 yrds.hope make out on that tv i personally would change the tube.refurbish should work fine.all my tv are analog i just bough a sansuai 27 analog because i use dish net work already ditigal to analog for 14yrs.stay in touch i will be here.jeffie ask me to help on issues if i know the answers.she a fine lady.