Hello all, I have replaced convergence IC's previously on my Sony rear projection TV with no problem; however, I recently replaced the convergence IC's on my parents Mitsubishi VS-60607 rear projection TV with no improvement in the convergence. Attached are links to a few pictures illustrating the convergence problem. I am able to adjust the convergence manually through the advanced menu as well as the service menu; however, I'm unable to achieve the needed alignment. I've de-soldered the IC's once already and re-soldered them to try and eliminate a poor soldering job and I'm now hoping that I could get some guidance as to what else I need to consider when looking to fix this TV. It appears that I have a sever issue with the convergence and have had "foldover" mentioned to me a couple times as well. I've also taken pictures and created a short slide-show to help others access and repair their TV located below. The only symptoms of the problem is convergence as displayed in the pictures below. The TV does not power off at any time or display any other errors. Any help would be greatly appreciated.
VIDEO OF REPLACING IC's (watch in HD to read captions)
Any help would be greatly appreciated!!!
CVinje
Remarkably, I was browsing the Craigslist ad in my town and low and behold, somebody was giving away the exact same model TV as the one with the convergence problem I mentioned above. This model would not power up; however. So after picking it up and swapping the entire boards with the convergence IC's and everything and powering up the TV, everything was looking fine and I was able to achieve proper convergence! I tested all of the resistors around the IC's on the "bad" board - using the schematics from the service manual to determine which resistors were in-line with the IC circuits and they all tested fine - I even took to the time to compare them with the values of the resistors from the known good board and everything matched. From what I can determine, there are no pico fuses on this TV (I'm no expert, so I'm not sure, but I don't think there are any per the service manual)?
I'm stumped and don't know where to go from here with that other TV. I'd like to get it working as well, and am greatly enjoying the challenge at troubleshooting it; however, I might be in over my head. So, I hope to get some additional guidance on what my next step should be as well as what I could do to troubleshoot the no power problem. The big problem with that board is the the convergence seems so far off that the grid pattern displayed does not even line up with the top of the TV. I'm used to, and assuming I should have, a set grid that would provide me with a proper convergence to move the red and blue grids to meet. It seems as though that would be green in this situation; however, the green grid is completely skewed and not even in line with the physical top of the screen, leaving me with nothing to align any of the colors to. Do I need to use an external grid to align everything, or is there something else failing here that I'm missing beside the convergence IC's.
Is there a way to test for proper voltage reaching each pin of the convergence IC's?
Would it be prudent to desolder the now known "good" IC's from the working board and replace the one's I purchased from MCM Electronics and see if perhaps I received defective chips from them?
Any help would again be greatly appreciated.
CVinje
Thanks!!
Thank you kindly for the compliment. I'm trying to do my part in learning my share before asking questions and expecting this to be easy.
As I mentioned in my earlier post, the second TV I got had a power up problem that I have not yet begun to troubleshoot; however, by taking the entire board with the convergence IC's and placing that in the TV I originally had with the convergence problem I started with I was able to obtain proper convergence! Thereafter, I tested the resistors in circuit and compared the values between the two boards and everything seemed to match. Visually, the capacitors seem OK, unfortunately, I don't have an ESR meter to test them so I'm looking at trying to find a way to test those with my millimeter. Thereafter, there are a couple transistors in the circuit I'll test as well. I won't be able to begin working on this set for a few days, but my plan is as follows:
1) Reinsert and connect the "bad" convergence board.
2) Double check the ability to adjust the colors up/down & left/right to try and eliminate the chips as the problem.
3) Dependent on the results from step 2:
If Colors All Move: Troubleshoot the problem by using the service manual and adjusting focus / skew / tilt, etc. There's a pretty extensive process that might be able to correct the apparent gross misalignment of the reference (green) grid.
If Any Color Immobile: Begin tracing the circuits via the schematics and locate all associated resistors (to include surface mount (smd) resistors) and test with multi-meter. At this point I'd consider even taking them out of circuit by desoldering them to ensure my test results are accurate. Also, closely examine the capacitors in circuit. Finally, test the transistors as well. Depending on those results, complete the testing by taking voltage readings at the associated pins on the convergence IC's either by removing them completely and testing or temporarily soldering wire leads to the pins while the IC's are still installed.
4) If the service manual adjustments to try and correct the reference (green) grid fail, I'll start at step 3, part 2.
One of the assumptions I'm making is that since I was able to achieve convergence with a different board without having to adjust the deflection yokes or lens positions for focus, I can ignore that as a problem when attempting to get this other board to work? Not sure if that's a correct assumption though.
I must admit I'm greatly enjoying this challenge and hope to be able to learn as much as I can from this opportunity. Hopefully I don't get too frustrated and will be able to take something away from this. Thanks to anyone and everyone that provides assistance online regarding these types of topics.
CVinje
seeing your grid pics, the first thing that came to mind was the yokes got bumped, or somebody tried to adjust convergence in service menu before replacing the bad ic's.
You may have to spend some quality time with the manual on setting up the geometry. See if the manual shows the grid dimensions, find the center of the screen by making an X across with string, and go from there, green first.
While you have the board out check for signs of coolant leaks beneath the crt rack, check the whole board for cracked solder joints.
Sounds very prudent - I have looked at the board under bright light and a magnifying glass and also looked for coolant, have not seen any problems on either board. I've begun to suspect the same problem - yokes adjusted or convergence really modified; however, would that still be as likely the cause of the problem since I was able to achieve proper convergence when using the signal board from the other TV (with different IC's and everything)? This TV was moved while on it's side in the back of a truck for some distance - not sure if that is the cause of the problem though. What stumps me about the yokes or any physical problem is that I was able to achieve proper convergence with the other board (the green reference grid was even straight). I'll post the results when I get some time to work on the TV in a few days.
Thanks very much for your reply!