Hi,
I had convergence issues with my Misubishi WT-42315 a month ago. I checked solder joint on convergence modules and resoldered pins 14-18 on the horizontal module. The picture looked perfect afterwards. I would note that on hte advanced convergence setup screen, the vertical lines seemed to have blue fringes even when the blue was centered. My TV is hooked up usinsg a DVI cable to a HD cable box (scientific Atlanta) and has been working perfectly. The other day I found the DRV manual and read about setting the box to work with widescreen TV's - 1080i format even on non-HD channels. I'm thinking the box was probably set up for this anyway. When I exited the setup wizard, the TV turned off. Now the TV won't power up , the miroprocessor is good and I get the shrot circuit protectiuon error code. I assume this was coincidence and that my IC's have gone bad. I have read that fuses might have been blown. I assume these are not glass tube type fuses. I have the service manual, what is the symbol for in-line fuses and will they be located on the main circuit board. If one or more needs to be relpaced, can I buy replacements at radio shack.
thanks in advance
mike
No these will be whats call pico type fuses. if you have an electronic schematic or service manualk, e-mail me a copy and I will have a look. [email protected]
Ok, I have the scoop on this set. First thing to check on the main board you sent is pins 4 and 5 on the convergence IC's. They should have 24 volts + and 24 volts -. If one or both of these voltage are missing, on the power supply board, off of pins 21 and pins 22 of T9a50 are two small fuses. I am not sure what types they are as I did not get any parts list with the schematics, but you can look these up with your manual. Ther are maked F9A04 and F9A05. These are the two 24 volt line fuses. If one oe both of these 24 volt sources are really low, disconnect the b+ and B- pins on the IC's to see if this brings them back up. If not, we will look into this further. Hope this helps. Good Luck
larry and I have been corresponding via email - just to get the readers up to date:
Mike : thanks - I tested voltage on convergence chip +24 was OK using ground pin. I have not thought about negative voltage in a while but I assume I test the -V by reversing the voltmeter leads - red to ground and black to pin 4
in the IC. is that right? IF so then no voltage on the negative side - I
will check fuses later and post my results. When I open it up and test fuses
is it proper to test resistance across the soldered fuse to see if it has
popped or are these not all or nothing fuses? and when U say disconnect the
b+ pins on the IC's you mean desolder pin number 4 on the STK modules. In
the parts page, the fuses are designated LF251 5A (-V) and LF251 10A (+V).
Larry: Yes you simply reverse the leads to measure negitive b+.
No disconnect all the pins that are red on the
schematic on those IC's and yes a fuse will measure a
short or open No inbetween.
I checked the resistance on the two fuses. the +24 volt 10A was ok. The -24 volt 5A showed no resistance - thus it has popped. I took a pic and showed a guy ar radio shack the fuse, he said it was a pig tail fuse. I had no idea what to look for - I have encled a pic of the offending F9A05 fuse. It is the green one.
If you can fit a small pigtail fuse in there go for it, but dont forget to replace both of the Convergence IC's first, then the fuse.
One last bit if advice needed. All the solder points are exposed from the under side of the light box. Since the TV has been unpluged for a week do I have to worry about residual electricity in the machine. The last time I resoldered the ic pins I grounded the anode leads. Is that necessary?
Is there any benefit to using silver bearing solder?
thanks for you help
No you should be ok as long as you do not mess around with the high voltage leads. Use the proper solder such as 80/20 or 60/40 is good. You can use lead free solder if your worried about the lead content.
After installing the fuse and the IC's I was hoping of coming back here to sign off with a thanks for all your help, but.....................
I found a pico fuse and installed everything today. It went smoothly. The TV turns on and stay on but the menu and picture is blue. How bad is that... and can I fix it?
Could the convergence modules I bought be bad. I actually bought two sets - one from MCM and one set from audio lab of GA. (five years from now when they go bad I'll have a backup set). The Audio Lab of GA were STK394-250A-E. I was told there were OEM and a lead free version. On the IC's it reads STK394-250A. These are the ones I used.
anything is possable but doubtfull that all the IC's are bad. it might be time to start looking at other componets in that circuit. or to call in a pro to assist you in this repair.
IC were good. Steve from ecoustics forum suggesetd tht nothing would cause my symptoms other than I had inadvetantly left something unplugged. IT turns out that simply sliding the light box in and out and turning it over to solder had slightly unplug a socket on the video board. After instering it the rest of the way - All is good. thanks for your help.
Mike
Glad to hear you figured out your problem!
Hey larry - all is fine with the TV - since you were so helpfull before might i ask a digital camera question. I plugged in a transfermer to my digital camera - not one specified by the camera manufacturer - lower voltage by half a volt but it might have had higher amps. anyway the transformer probably blew a fuse - no power when plugged in and now no power when i use charged batteries. if the fuse blew for the plug in would that affect the battery circuit. I have a circuit diagram.
Did you check the polerity of the transformer before you plugged in the camera, ie the plus and minus leads on the camera and the transformer. Also was it a DC transformer. if the +or the - was wrong the camera blue a fuse, a circuit protector or a protection diode they put into electronics in case this happens. In eather case you will need to send the camera in for repairs as most of these cameras have no replacement parts available except the boards. Is this camera worth this? if it is, my best advice is to send it in for repair. Good Luck and let us know how you make out with this.
polarity was ok, yes a dc transformer. based on the diagrams would a blown fuse make the batteries not function. could more things a diode perhaps - have gotten fried. i had to purchase a set of pico fuses wehn i fixed the tv. i plan on bypassing the fuse to see if it fixes the camera -
thanks for your help
mike
i wonder if u can even see the circuit diagram
Do not jump out the fuse!!!! you will burn up something if the fuse is open. Check the zener diode there if the fuse is open.
how would i check the diode? is the diode the triangular shaped thing in the circuit diagram?
Yes it is, you have to check it with a multimeter, in the resistance scale it should read one way on low ohms but not the other way.
hi there im just have this problen with my mitsubishi wt42315 it does not turns on eviritig star wen im turn on the tv and the picture just shork and then does not turns on im was thinking about maivy is the str394-250 but im dont know sombody can help mi please
You most likely need to replace the convergence IC's you can get the proper kit of convergence parts at tvrepairkits.com. They have all the correct parts for your set!
i have problems with the mitsubishi wt-42413 rear proj tv..ok so it shuts off after a while of being on then i have to wait like 30 min to turn it back on when its cooled down...i checked the error while it was off and the code was 24 the tv kept shutting off with the same error each time. ok so now i left it on all day while the cable was on and it shut off. so i thought maybe in 30 it would turn back on.. but i guess not.. the error code is 24 now.and i let it sit for 24 hours unplugged. tried to plug it back in and try it but now luck . same thing,..and now its error 24 and wont turn back on without instantly shutting off without showing picture..the tv was replaced by a tech guy a few years back when a friend owned it. and i looked at the IC's and they are the exact same except the numbers on the top right corner of the chip they are both stk394-250 sanyo.i have the service manual and took the tv apart and resoldered the IC's and applied new paste but i guess that wasnt the problem.. i was thinking about getting new sanyo IC chips and new capacitors and checking the fuses... my multi meter is on its way .. LARRY or somebody please help i like this tv it has great picture .. i can send u the sevice manual through email.. if so please email me at [email protected] thanks alot.
The best advice I can tell you at this point is to go to tvrepairkits.com and order the complete convergence kit for your model of TV set, no need to search and order multiple parts from different sources and pay multiple shipping fees! The kit comes with original Sanyo STK ICÂ’S , not those cheap aftermarket or china made ICÂ’S full pictorial directions, the thermal paste, resistors, the correct Pico fuses, AND free live on-Line tech assistance in case you run into a problem with the repair. They ship out 2 to 3 day Priority mail, the next day in most cases,
try replacing the ic's as the first procedure as I have seen many of these ic's go bad after they had a bad connection on them as it stresses out the ic big time!!!!!!!!!!! LARRY
DILLON
ok thanks alot thats what im thinking about doing this weekend... is there a way you can email me the capacitor replacement guide for this model cause i wanna do that while im at it to..and one more thing since i have already ordered my stk's off of ebay that are the same exact model# and brand can you tell me the resister specs that are included with the kit thats on the site you sent me ? like whats size K and that , any help would be apriciated being that i didnt ket the kit you sent the link for so i dont have a guide.. unless anyone has a guide for the model i have . mitsubishi wt-42413 thanks alot ..
are you positive the ic's are original stk ic's?????? if they are not you will be sorry and to save a few bucks you that is just crazy!!!!! always get the original convergence ic's and original caps go to tvrepairkits.com for original capsand ic's.that cost less than a few bucks are not or i cannot see how they could be original ic's as they are pretty expensive nowadays!!!!
Larry D
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