Home Theater Forum and Systems banner

1 - 20 of 27 Posts

·
Registered
Joined
·
15 Posts
Discussion Starter #1
Hi Lcaillo, I am working on my old Rear Projection TV Mitsubishi VS-5043 for Convergence problems that it has had for some time now. I was actually given this TV by my father about 8 months ago because he got tired of having to hit it to get it back into convergence and went and bought himself a new Phillips flat screen. Ignorant as we were, my fiance and I were happy to continue smacking it around because the picture was so good when it snapped back in line.:duh: Now I fear we have allowed the problems to get worse. Last week it refused to cooperate, no matter how much we slapped it around, it would no longer straighten up, nor would the red cross hair so much as budge when asked from the convergence setup. So I decided it was finally time to figure out the real problem. After digging around on the web, I finally came upon your wonderful forum (something I wish I had done 8 Months ago) and saw where you had told someone to re flow the solder connections to the STK's. Well I did that,and in the process also found a blown inductor on the board which I replaced, and actually got control back of my red cross hair. However my convergence is still not fixed, and leaves a really wicked drop shadow on all on screen displays. I assume that one of my STK'S must have finally bitten the dust. Could you please point me in the right direction of a vendor that would have a kit of all the common replaced convergence parts for my particular TV and hopefully some instructions? If it helps the amps are STK391-020 and it uses 3 of them. I am a little worried because I found the one 10uH inductor smoked in half Next to the middle STK on the board and am afraid more components may be harmed(although none are apparent). I have recently been layed off from my employer of 9 years, and cash is tight, so calling in the experts is not an option. I have a multimeter, and a soldering iron, and am pretty good at following directions, when all else fails. Any help you could offer would be greatly appreciated.:hail:
 

·
Plain ole user
Joined
·
11,121 Posts
I don't know of any kits for this set. ACME or B&D are my preferred vendors, but PACPARTS is another good one who supports our forums. The inductor likely burned due to a bad output IC. Verify all of the voltages at the ICs before you install new ones.
 

·
Registered
Joined
·
15 Posts
Discussion Starter #3
Thanks for the quick reply, i have already removed the heat sink in preperation of replacing ic's would it be harmful to power up long enough to check voltages? how do i know what voltages should be where?
 

·
Plain ole user
Joined
·
11,121 Posts
You can run most any set with the chips removed to check the voltages.

Yes, Acme in Orlando.
 

·
Plain ole user
Joined
·
11,121 Posts
Refer to the schematic.
Posted via Mobile Device
 

·
Registered
Joined
·
15 Posts
Discussion Starter #12 (Edited)
Sorry, I have been searching for a free one, cause I just don't have the funds, at the moment. I did receive my parts today and went ahead and removed the ics, and checked all the voltages at the ics holes to ground on the board after removal, against each other and I recorded the voltages for future reference. They are all pretty much the same voltages pin per pin, ic slot to ic slot. So without schematics, I believe the voltages are ok. However after checking voltages, I installed the new ic's I received from ACME, and I still have the drop shadow. I analyzed the image carefully and it appears that my green image is hour glass shaped pulling in on either side in the middle. on the 5 point convergance setup the center crosshair is fine but each corner setup the green crosshair skews off towards the middle( and if my assumptions are correct the middle ic controls green and that is where the 10mH inductor blew.)I am still worried that something else on the board was harmed when the 10mH inductor blew, but I have so far been unable to find any obvious bad components. I have checked every fuse, and pico fuse i can find, but all read good to the meter. :help: Also when I installed the ic's I used
Arctic Silver heat sink compound lightly applied, and double and triple checked all my solder connections, and am absolutely positive there are no cold solder joints or solder bridges. and nothing is unplugged. I really miss my TV, but do not want to run it till it is fixed. what do i do now? heres some pics too...



all your help is greatly appreciated:yes:
 

·
Plain ole user
Joined
·
11,121 Posts
Your problem will require some troubleshooting. If I was servicing the set, I would refer to a schematic to become familiar with the circuit before I would know where to look for potential problems. As suggested in the sticky, I do not recommend trying to fix a problem without having the documentation. $16 is not a lot to spend to get a manual.
 

·
Registered
Joined
·
15 Posts
Discussion Starter #14 (Edited)
Ok, I Acquired the manuals, but I'm not really sure what I am looking at. I went ahead and attached them to this post for you to take a look at if you would be so kind. (who knows, maybe you could use them yourself in the future) Maybe then you could point me in the right direction....I feel sure this should be a simple fix, but I guess I'm an even simpler troubleshooter, LoL........I'm more of a computer geek than a TV geek, if it were my computer doing this it would be a simple software adjustment. Again, I can't thank you enough for the help.
 

Attachments

·
Plain ole user
Joined
·
11,121 Posts
Thank you, but I have the paper copies of the manuals. I also subscrib to several services where I can download most manuals, but I do not redistribute them becuase it violates my contracts and copyright laws. I cannot do specific research and provide specific step by step trouleshooting for the forum. This is clearly beyond the scope of the forum which is intended to provide general information and common symptom repair relationships.

Read the convergence repair sticky very carefully. The first ten posts give a good explanation of the common problems, how the circuits work, and what to check for. You have to have supply voltages and the related parts have to be intact. The schematic will show the layout of the circuit.

A great deal of time goes into creating and udating this information and responding to posts with general advice. If you need step by step help beyond this, you may not be a good candidate for a DIY project at this level and should consult a professional. Not everyone can fix their own set. I (and many other professionals) do this for a living and cannot be expected to walk you through every step and teach you troubleshooting skills long distance. Contact me personally off forum if you need to contract my time.
 

·
Registered
Joined
·
15 Posts
Discussion Starter #16
Well I still thank you for your help getting me this far. If you are ever in Tulsa, send me a message and my fiance and I will buy you dinner.(Maybe I'll be employed again by then, and can take you out for a steak 80) ) I will continue to beat my head against this thing until I figure it out or blow it up.:yes: I will post my findings, if I figure it out in case it can help someone else with hourglass shaped green image. Keep up the good work sir.:T
 

·
Plain ole user
Joined
·
11,121 Posts
Don't get frustrated. Take your time and be methodical. Power supplies are the first things to verify. If you don't understand something in general about the process, just ask. I can't go figure it out for you but am very happy to help you understand the basics. Read and re-read that convergence repair sticky (first 10 posts) and make sure you understand how the circuit works. It is just a six channel amplifier with big op-amps in those ICs. Not rocket science. You have inputs and outputs, feedback, a few related caps and resistors and power supplies.
 

·
Registered
Joined
·
15 Posts
Discussion Starter #18
All of my voltages appear to be spot on, and all the resistors I have checked that pertain to that circuit seem fine. I don't have an o-scope or function generator, or even an LC analyzer, however the capacitors, when checked with a digital multi-meter give the appearance of working, ie they seem to "charge" while trying to read resistance. I have checked resistance from each leg of each STK to it's nearest trace neighbor, to be sure there was no damage to the board from failure/replacement, and all check good. Also there is absolutely no visual sign of any component failures on top or bottom of the board. Now that i have replaced the STK's and the one burnt inductor, could it be in any way possible that this green hourglass image is something I can correct in the factory level setup menu's listed in the manual? If so what would this problem be called? I am working on getting a hold of a copy of the Digital Video essentials dvd, so that I will have a source signal to feed it while testing. At present it looks like it will take a couple of days to acquire. Could you recommend any other video "test signal" resources? I hesitate to start making changes in these factory setups, if that in no way could help. But if it comes to that I will, making sure to record all original settings first......I ain't giving up yet.............:paddle:
 

·
Plain ole user
Joined
·
11,121 Posts
I would have assumed that you tried to correct the problem in the service mode for convergence. That is what it is there for. YOu should look at the values on the parameters in the convergence mode and if any of them are at 127 you may have corrupt data in the EEPROM. If this is the case, record all data and you will need to do an EEPROM reset in the OPTION menu. Then all adjusments will need to be reset and convergence and geometry will have to be done from scratch. This is a BIG deal so DO NOT do it unless sure that it is needed.
 

·
Registered
Joined
·
15 Posts
Discussion Starter #20
Thank you, that's where I will go next. I didn't go there first because of the blown inductor, I wanted to be sure there were no other burned out components. I was afraid I'd make a simple fix into a simple nightmare if I started adjusting for bad components. I am fairly convinced now that the circuit is good so i will start going through this process next. I am still trying to get a hold of the video essentials DVD, may get it hopefully tomorrow. Is there any other reference resources you could point me to for going through the convergence and geometry setup? I am definitely gonna owe you a steak dinner when this is over........:hail:
 
1 - 20 of 27 Posts
Top