intergrated tcon board ic rt6939 vestel polaroid p55up0277a

[Diah]

Re: intergrated tcon board ic rt6939 vestel polaroid p55up0277a

on my 17mb120 theres a u11 and a u13 ,but no u 12?
but on the circuit diagram u 12 ie shown.

are you sure ? on the downside did you check too.. look on number of it in schematic and look after all SPI with 8 pins

[arizanotlari]

Re: intergrated tcon board ic rt6939 vestel polaroid p55up0277a

i see,,, so you have DC to DC correct working before replace COF.

the signal which come from main boards via R440 100R connect to lvds socket pin30

Yes. Tvs all functions working correctly jus missing same panel pcb voltages.

[jimbofz]

Re: intergrated tcon board ic rt6939 vestel polaroid p55up0277a

on my 17mb120 theres a u11 and a u13 ,but no u 12?
but on the circuit diagram u 12 ie shown.

[Diah]

Re: intergrated tcon board ic rt6939 vestel polaroid p55up0277a

this set had 2 SPI U13 for MBOOT. at your case its function... and the other U12 for MFC this is i do suspected.. MFC the displaying of picture.. normally the SW of vestel before we do have 3 parts 1-MBOOT.bin 2-MFC.bin & 3-opertion firmware. if MFC corrupted no display as yours condition.

[Diah]

Re: intergrated tcon board ic rt6939 vestel polaroid p55up0277a

heres the pics ,
ive studied cct vbyone/lvds options
and found r440 shown as : L dim en pin 22
on the main board socket for lvds pin 22 is earth
and pin 30 doesnt appear to have any connections to it ?
after removing main board and tracing pin 30 ?
i must be missing something

could you locate on boards the U12 the MFC SPI 4Mb ?

[jimbofz]

Re: intergrated tcon board ic rt6939 vestel polaroid p55up0277a

Diah misunderstands me. Your panel is short circuited. I replace this ic but still not working. I send tv to panel repair workplace and they replace cofs.

https://yadi.sk/i/_6VKMJQ4rQYiAA This is circuit diagram of mb120.

i didnt realise that it was possible to replace cofs

[jimbofz]

Re: intergrated tcon board ic rt6939 vestel polaroid p55up0277a

for this cheap sets / mainboards don't have extra video processing ICs also usually all signal come from Main IC direct via LVDS to the panel.

if you could upload focused photos on the main boards and the LVDS sockets from up and down side if there any remark on the pins.

heres the pics ,
ive studied cct vbyone/lvds options
and found r440 shown as : L dim en pin 22
on the main board socket for lvds pin 22 is earth
and pin 30 doesnt appear to have any connections to it ?
after removing main board and tracing pin 30 ?
i must be missing something

[Diah]

Re: intergrated tcon board ic rt6939 vestel polaroid p55up0277a

Diah misunderstands me. Your panel is short circuited. I replace this ic but still not working. I send tv to panel repair workplace and they replace cofs.

https://yadi.sk/i/_6VKMJQ4rQYiAA This is circuit diagram of mb120.

i see,,, so you have DC to DC correct working before replace COF.

the signal which come from main boards via R440 100R connect to lvds socket pin30

[arizanotlari]

Re: intergrated tcon board ic rt6939 vestel polaroid p55up0277a

hi did you trace the source of the enable voltage from the main board? as Diah
sugested ?
ive studied the circuit and cant see where the enable comes from
can you help? thanks

Diah misunderstands me. Your panel is short circuited. I replace this ic but still not working. I send tv to panel repair workplace and they replace cofs.

https://yadi.sk/i/_6VKMJQ4rQYiAA This is circuit diagram of mb120.

[Diah]

Re: intergrated tcon board ic rt6939 vestel polaroid p55up0277a

for this cheap sets / mainboards don't have extra video processing ICs also usually all signal come from Main IC direct via LVDS to the panel.

if you could upload focused photos on the main boards and the LVDS sockets from up and down side if there any remark on the pins.

[jimbofz]

Re: intergrated tcon board ic rt6939 vestel polaroid p55up0277a

You are right. Thanks for information.

hi did you trace the source of the enable voltage from the main board? as Diah
sugested ?
ive studied the circuit and cant see where the enable comes from
can you help? thanks

[jimbofz]

Re: intergrated tcon board ic rt6939 vestel polaroid p55up0277a

What is the resistance reading on HVADD and VONE against ground?
So now you have 1.8V, 3.3V, and 1.05V that you did not have before in post #1? What did you change?

well i was concerned that there was 250ohm to deck across the 4 caps in parallel i removed them ,
same
so removed the coli marked 6r8
same
i looked at other connections at rear of panel only to find there are LINKS inside the pcb ,not just twin sided print these links appear as pin sized dots ,when i used fibre pencil on them and checked resistances between various points i found a connection that was oc
vertually impossible to see even with my head up magnifier .
also if you shine a light through the board you can just make out these links .
once i soldered the pin sized links i then ran a fine wire to make a good contact ,it makes me wonder these links are so fine that what current they could handle would be minimal.
now that i have some voltages i now have the coil 6r8 dropping .4v across it from 1.4v to 1v so im beginning now to suspect the ic

[budm]

Re: intergrated tcon board ic rt6939 vestel polaroid p55up0277a

What is the resistance reading on HVADD and VONE against ground?
So now you have 1.8V, 3.3V, and 1.05V that you did not have before in post #1? What did you change?

[jimbofz]

Re: intergrated tcon board ic rt6939 vestel polaroid p55up0277a

Hi.
Some questions
1 can you check the tensions on the points indicated?
2 Can you check if you have short circuits on the points indicated?
3 can you please insert a picture of the panel tag?
4 you can put a retro tv label photo please

after replacing removed components and checking all cap values ,i now have the following voltages on the red arrows you put on the pic ,starting from left to right 1.07v then 12v and earth across cap
next the cap below the 220 coil12v
the cap on left of 4 caps in parallel vone .25v
the cap to right of chip rt6939 12v
and finally the cap above the220 coil voffe .24v

so on the marked test points i now have:voffe .14v bad
vone .25v bad
1.8v good
3.3v good
vcc1.05v good
hvadd ov bad
hvdd 12v good .
do you have any idea how to find the enable pin for the ic ,
i assume it must go high to turn on the ic and start the vone and voffe voltages?

[arizanotlari]

Re: intergrated tcon board ic rt6939 vestel polaroid p55up0277a

arizanotlari DC to DC Enable work within signal come from main boards to switch it ON.

if you have the schematic of the MB would be helpful to trace the signal source

You are right. Thanks for information.

[jimbofz]

Re: intergrated tcon board ic rt6939 vestel polaroid p55up0277a

thank you for your reply, very much appreciated. So my "capacitor" is actually a fuse so it should have 0 resistance

remote is the original one, is not a replacement/universal type.

ok it was worth a shot ,in that case you could have a faulty main board for two reasons;

1 the problem with remote functions
2 the enable on for these ics is from the mainboard according to post from diah
he has helped me in the past and he is very knowledgeable.

[nos_feratu]

Re: intergrated tcon board ic rt6939 vestel polaroid p55up0277a

the component circled in yellow is not a cap its a fuse ,its confusing as it looks like a cap bur slightly bigger and grey in colour whereas the caps are usually beige ,with regards to your fault are you using the original remote control as some will opperate in/out sby ,but may not have correct codes for as example volume ,just a thaught.

thank you for your reply, very much appreciated. So my "capacitor" is actually a fuse so it should have 0 resistance

remote is the original one, is not a replacement/universal type.

[Diah]

Re: intergrated tcon board ic rt6939 vestel polaroid p55up0277a

Hi.

Vestel chassis have scart output (cvbs out) but this line not worked. You can not connect another tv.

I replace this ic 1 month ago but tv not worked.


Panel is faulty if backlight working.

arizanotlari DC to DC Enable work within signal come from main boards to switch it ON.

if you have the schematic of the MB would be helpful to trace the signal source

[arizanotlari]

Re: intergrated tcon board ic rt6939 vestel polaroid p55up0277a

Hi.

Vestel chassis have scart output (cvbs out) but this line not worked. You can not connect another tv.

I replace this ic 1 month ago but tv not worked.


Panel is faulty if backlight working.

[Diah]

Re: intergrated tcon board ic rt6939 vestel polaroid p55up0277a

i use scart i/p as it will auto select scart (as i cant see any on screen menu) then i can set vol mute ,and go in and out of sby ect

i think yours set and the other threat one of same panel the issue at main boards..

same to yours idea by using scart but this time use it as out put from the tv to to other one,, to check if you can see the menu. or any channel sign.

edit.. of course yours scart cable socket should have at least output at one end.