Greetings, I had a lot of fun repairing my old RCA 60" Convergence correction problem - thanks to this forum... Its been a while and that TV is still working as good as new!
Now to the new adventure... We purchased a Toshiba 72MX196 in 2006, while many others had trouble with their Toshiba DLP, ours did not have much problem until just before this Christmas!
The picture was getting a tiny bit dimmer so I ordered original (claimed by seller) lamp but sellers sent aftermarket, it work a bit but need a few restart to light up. I questioned the seller and they told us to return saying it was their supplier mistakes. I re-install original lamp, it work fine but this time it need a few re-start too to light up. A week later, it just refused to light up anymore. When turned on, I got solid Blue LED, then when it refuses to start, the Yellow LED (Lamp) flash 3 times every 3 seconds, pause a bit and did this for 5 times, a total of 15 flashes. The error codes in the manual does not show this sequence and calls to Toshiba C/S is almost useless, just said replace lamp.
I ordered original lamp (made by Phoenix) from Discount for $125, did the same "no light up re-start" thing so opened up the back cover, remove the light engine assembly (very carefully) to get a visual at the Ballast Driver (RUBYCON RPB-5468BA Toshiba P/N V71A00000100). This part is not available anywhere except some electronic company in Hong Kong.
I checked the usual resistor that burned out on other similar ballast but every thing seems at par. I re-flow some solder of heavier pins and re-install the ballast. plug in power and Yellow LED Blink a few more times before powering up. Hit power on remote, Blue LED came on, in a few seconds, I have dim picture for about 60 seconds and poof! no light. While the TV tried to restart, I went to the back of the TV (with cover still off) to look at what is going on - the lamp light up yellowish color, no too bright and start to brighten up to white light immediately, but within 5 seconds, the lamp shut off again. This tells me the lamp is getting power from the ballast driver but what is shutting it down? I by passed the overheat sensor with same result.
I read from the other forum all sort of things that others (with older DLP) are doing to fix the ballast driver and many are successful. At $4000, this is a very expensive TV but, today's 70" LCD can be had at $2000 so I don't thing I am going to sink much money into this TV.
It would be interesting though to find out what ticking... anyone with experience repair ballast driver place chime in... I took lots of photo on this repair and I will post it as soon as possible.
Cheers for the coming new year,