Home Theater Forum and Systems banner
1 - 7 of 7 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter · #1 ·
Hey, first off thanks for any help that you guys can provide. This looks like a great board filled with people that know what they are talking about.

I have a Mitsubishi WS-B55 that my wife and I picked up from a co-worker of hers for $25 non-working. I was looking for a new project so I was into it! When I tested it, it did the from what I have read standard green light blinking for 70 secs or so. When you would press the power button you could hear a click and then another click about 2-3 seconds later. I did the error code test and came up with error 22. I did some searching and found that I should check the fuses. When I checked them everything was fine except F9A05 which I found was related to the convergence IC. I jumpered the fuse with a jumper that contained an inline fuse of the same value just to see if that would blow also, not knowing much about these tvs I was hoping it was an isolated power spike or something, and I know it is never good to jumper a fuse but I didn't really have much to loose and I used a fused jumper. Anyway that fuse also instantly blew. I then pulled the center most board out of the tv that contains the convergence IC (my set only has one) and the fuse that I mentioned above. I desoldered the convergence IC and then put the board back in the TV to see if the TV would start because I read if the convergence IC was bad it would boot without it. I again jumpered the F9A05 fuse (i know thats bad) and after it did its 70 secs of green light flashing after plugging in, it did start. It just did not have the convergence correction obviously.

So here is my question. Is this FOR SURE a problem with the convergence IC being it works without one installed? Are there any other things that could be bad? I have read that it is a good idea to check the resistors in the area of the convergence IC chip. They all look fine but I will be testing every component on that board that I can being the new convergence IC won't be here until at least Wednesday.

I am open to ANY and ALL ideas, questions, and suggestions.

I took pictures the whole time that I was working on this so if you need any pictures I have them.

Thanks!!!
 

·
Registered
Joined
·
4 Posts
Discussion Starter · #3 ·
Thanks that thread you reccommended is very informative. I am going to replace the fuse and the IC and hope for the best.

I did see a post about checking the 24v power supply. Do I check that at the point where the 2 wires are jumpered from the power supply board to the board that has the convergence ic on it? Do I test it hot?

And if I do get it running, do you adjust the convergence via the on screen commands?
 

·
Plain ole user
Joined
·
11,121 Posts
You test the power supply voltages at the ICs. Be sure to check the resistors.

The controls for convergence are described in the service manual and are operated by remote control in the on screen menus.
 

·
Registered
Joined
·
4 Posts
Discussion Starter · #5 ·
Ok I checked all the resistors that it recommends. When I check the 3.9 ohm resistors (example R8C30 which is rated for 3.9 ohm at 2 watts) I get a reading of 2.1 to 2.2 ohms each. I figured this was normal being they are parallel. Is this a normal reading for these? I just wanted to check so I don't fry the new IC that comes tomorrow.

Thanks again!!
 

·
Plain ole user
Joined
·
11,121 Posts
Yes, 2 3.9 ohm resistors in parallel would be half that resistance. Add a bit for lead resistance and you are probably fine.
 

·
Registered
Joined
·
4 Posts
Discussion Starter · #7 ·
I know it has been a couple of years since I last posted but I wanted to update with information that might help some people. After replacing the convergence IC on my tv everything worked fine up until yesterday. Before we left for a party yesterday the power went out. When the power came back on I noticed that the green timer button was blinking constantly. I didn't have time to mess with it and I figured it would be done by the time we got home later that night. Well I finally got around to using the TV today and the light was still blinking. After some searching google I found that it could be the 7 capacitors that are known to go bad on the DM board. I pulled the DM board and found that the capacitors I needed were 16v 1000uf. I was getting ready to order the replacement capacitors and I had an idea. I repair game consoles on a daily basis and have a bunch of spare broken xbox 360 motherboards laying around. After looking at the capacitors on the broken xbox 360 motherboards the closest capacitors I could find to the value I needed was 16v 1500uf. I desoldered them from the broken xbox 360 board and used them to replace the capacitors on the DM board and it worked PERFECT! They were a little bit taller than the capacitors that were originally on the DM board but they were the exact same diameter.

So in short, if you have a broken 360 motherboard around you might be able to use the capacitors on there to fix your TV. :) Also, the 16v 1500uf capacitors seem to work great!
 
1 - 7 of 7 Posts
Top