A dead CRT was brought to my shop by a friend of mine. He said that this TV suddenly stopped working. I could see a stand by light but there is no high tension sound, no audio and no picture.
I took the cover off and scanned the area for bad capacitors and found no bad ones. I plugged it in and started testing voltages in the power section area. There was 300 volts reaching the main capacitor and there was 24, 110, 10 volts coming out on the secondary diodes in the secondary power section.
There was 110 volts reaching the HOT in the high tension area. Everything seems to be in order which brought a thought to my mind, that TV is in good working condition, it just needs a remote control to turn it on. The guy did not bring the remote control with the TV and when I called him, he said that the remote control is missing and he was using the channel buttons on the front of the TV to turn it on.
I un-hocked the buttons board from the main socket and cleaned it and made sure they are in good working condition. Tried it again but no luck. I called a friend of mine to ask him if he has a remote control for this TV but not locate one. I started thinking what this guy told me about the TV set. He said that because the remote control was missing, he used the channel buttons to turn it on. What if the problem was not the remote control but the EPROM computer chip? May be that chip was locking the signal causing the TV not to work.
There was a small tiny EPROM chip 24C08A located near the power section. I have exactly the same number in my shop. Soldered it out and replaced it with a used one. The moment I pushed the power button and hit the channel button, the TV came on. Usually it needs to re program the chip but since it was used, it worked fine.
That put a smile on my face. I called the guy and told him that the TV is working now. He asked me to find a remote control for it because he was planning to give this TV to his grand mother. I called the remote guy and asked him about a remote control for this TV and he said that I can use any made in china remote control to turn made in china TV sets.
I found a remote control in my shop, an old one actually and it was written on it, Fuji Japan (RS09-M449)but I know for a fact, it was a china made remote control and to my shock, the remote actually worked on this Grundig TV set. I was really happy to see that. The TV is working fine, the remote is working fine and the customer was happy to get both.