Coby TFTV4028 - Main board failure.

[kano donn]

Symptoms - Unable to turn on. Plugged in would display single blue light at middle bottom.

Assumed issues with main board. Looked for replacement board - Unable to find/Sold out.

Noticed multiple other folks had same issues and ended up replacing the 1000uF caps on main and power supply.

On main board, Middle cap was baddly damaged. Replaced with similar 1kuF at 35v.

Tv turns on and stays on.

Success \o/

[jccarter]

Re: Coby TFTV4028 - Main board failure.

i have one of these sets, it has recently failed, all of the electrolytic caps appear to be fine
however
c305 & c309 are melted beyond recognition,
it may have also damaged c101 from the heat/burn mark

is there any way i can get the values from those three locations on the power boardd please? anyone?
thanks!

[remaker]

Re: Coby TFTV4028 - Main board failure.

There are 3 different mainboards for the TFTV4028, depending on the panel and inverters used - maybe even different LVDS as well.

Coby 002-FV40-2813-00R for AU Optronics T400HW03 panel
Coby 002-FV40-2812-00R for Samsung LTZ400HF21-W01 panel
Coby 002-FV40-2810-00R for Samsung LTA400HM02 panel

They are all slightly different.

Good photos of that at shopjimmy.com, though.

I've been meaning to make a table of power supplies, inverters and mainboards that appear in a "TFTV4028" There are at least 3 different TVs in that model number.

The power supplies also vary: Megmeet MLT198TX and VP290UG02.

I have had two different models of this TV, and they both failed :-)

I may test the caps listed above.

[nutt318]

Re: Coby TFTV4028 - Main board failure.

I have the same tv Coby TFTV4028 and now its completely stopped working and now looking for some help. Some time last year if the power would go out and a few minutes later come on the tv wouldnt turn back on. The blue light was on but it simply wouldnt turn on. I left it unplugged for around 24hrs and plugged it back in and it worked great.

It stopped working again when we lost power and the power came one, same issue, left it unplugged for a day or two and plugged it back and and it worked.

Well now it wont come back on, when a power cord is plugged in the blue light comes on but the power button is useless. I saw a post about the main power board probably died, so I saw that shopjimmy.com had a replacement so I ordered it. I just got it installed and its still has the same issue, so it looks the the main power supply board is fine.

Looking at the main motherboard I dont see the usual signs of bad caps (swelling/leaking). I'm not seeing a marking for C305, C309 or C101.

Anyways could someone point me in the correct direction? Should I just replace some caps or can i test them?

Thanks!

[selldoor]

Re: Coby TFTV4028 - Main board failure.

Post good clear pictures of the front and back of the power supply board and close up of connectors then we can suggest a few tests.
With the new main board does the on/off still not work?
Please can you update your profile with country and mains voltage.

[nutt318]

Re: Coby TFTV4028 - Main board failure.

I'll get some pictures taken when I get home in a few hours.

The new board I bought is the power supply board, after installing it the TV still acts the same as it did before with the old power supply board making me think its an issue with the mainboard.

Also I updated my profile, I'm in the US.

Thanks!

[nutt318]

Re: Coby TFTV4028 - Main board failure.

I've finally got some pictures, hopefully you guys can point out what may be the issue.

http://imgur.com/a/CRIhO

Thanks

[nutt318]

Re: Coby TFTV4028 - Main board failure.

Any ideas on what I should try?

[xredhawk]

Re: Coby TFTV4028 - Main board failure.

change all caps on power supply, this tv looks the same as Polaroid

[hmendez86]

Re: Coby TFTV4028 - Main board failure.

bit confusing i have a coby tftv4028 main board is 2810, but the panel it is 400hw03 v.0 which i think the main board of 2813 should work....any suggestions ...