JVC EM48FTR turns on quick but image takes time

[keysal]

I have a JVC (Amtran) EM48FTR that is starting to take a while for the picture to show after turning on the set.

The unit seems to power on fine and normal with sound and ability to change channels, inputs etc. but no immediate picture. After a few minutes there might be a flash or two of a garbled line and it shows image and looks great. The delay of image seems to be getting longer and longer.

I opened up the back and the caps on power supply and main board look fine. The power supply has some Sam yeong and a rubycon while the main board has a mix of TK and Jamicon.

Main board replacements oh Shop Jimmy look to be hard to find but they did pop up with the eprom chip replacement as a common fix.

My question: is there a known defect in those eproms that requires replacement or are there bad caps or other components on the board that are damaging the eprom?

2nd question is if I buy the shop jimmy eprom will it be pre flashed with the correct software or is that something I would have to do after replacement? I have scoured the web for firmware for that TV and come up empty.

Any other advice in getting this TV back up and running well would be greatl appreciated.
Thanks

[dick_barton]

Re: JVC EM48FTR turns on quick but image takes time

Have you tried freezing the EEprom to see if it starts up quicker?

[keysal]

Re: JVC EM48FTR turns on quick but image takes time

I put the set back together to try that trick and for now at least the picture comes on quickly, before I had a chance try the freeze. No idea what cured it or if it will stay that way but for now it's good. I'll try the freezing if it happens again.
Thanks

[dick_barton]

Re: JVC EM48FTR turns on quick but image takes time

Hope it stays that way for you.

[keysal]

Re: JVC EM48FTR turns on quick but image takes time

As luck would have it after putting the set back together and connecting everything up and with in a day it started doing the slow turn on and sometimes the picture would cut out. Back light and sound and controls all keep working just the picture.

So I pulled it back down and opened it up and sure enough the screen comes on quickly when turned on. But then I thought about the Roku stick this TV came with that I leave in the MHL HDMI port. I plugged it back in and the Image did the cut out thing. I tried the inverted can of air to freeze the eeprom on the on the main board but it didnt change anything. I have another TV with a bad AS15 chip on a Tcon board and I have felt how hot it can get so I pushed on the eeprom IC and a couple of other ICs on the board to feel its temperature. All of them felt fine with no heat but the picture came back!

Right now I'm watching a YOUtube video of 12VoltVids fixing an LG through the Roku stick on this TV and it seems to be working fine now.

Visually looking at the boards shows a sloppy manufacturing by AmTran compared to the Samsung and Philips/Magnavox boards I have also repaired in the past.

My thinking is that I might try and reflow the IC legs on the eeprom with a fine tip soldering iron. I think the solder connections may have a fine crack that makes it work /not work arbitrarily with the temp and why pushing on it made it work again.

For now I'll keep the set disassembled and working until I get it to a point where I can repeat and fix the problem.

Any other ideas that it might be or does anyone think Im way off base?

[dick_barton]

Re: JVC EM48FTR turns on quick but image takes time

Try the reverse and use a hair dryer and see if heating up any part of the power supply or main board speeds up the shutdown.

[keysal]

Re: JVC EM48FTR turns on quick but image takes time

Was able to get the no image at start up again while the TV was down and the back was open. I pushed on the ICs and nothing happened until I pushed on the LVDS cable connection on the tcon board then the image popped back on and was fine.

So I opened the chassis some more to get to the board. No metal plates covering this TCON just a plastic section that holds the Speakers mounts and the has the mount for the Stand to screw into. The stand mounting is really chintzy and I suspect there is a lot of chassis flex.

The TCON is a 13VNB_S60TMB4C4LV0.0 with a model number of E29118D4A12ZK. https://www.badcaps.net/forum/attach...1&d=1465867849

After removing the LVDS cable from the TCON board I looked at the pins and noticed this.https://www.badcaps.net/forum/attach...1&d=1465867849
https://www.badcaps.net/forum/attach...1&d=1465867849

This is the first time this TV has been opened and it looks to me as if the cable has a kink in the end. Also the flat ribbon of the LVDS has two folds to make a 90 degree turn from the main board to the TCON.

I put the Tcon back in and hooked it all up and the image comes on nice and quick. But now there is another development. When using the Roku stick I get a "HCDP unauthorized content disabled" image on the screen where the media should be. https://www.badcaps.net/forum/attach...1&d=1465867849

Am I correct in assuming something related to the Tcon or LVDS cable is responsible for the HDCP? I would have thought the main board but that wasnt touched.

The mystery continues.

[keysal]

Re: JVC EM48FTR turns on quick but image takes time

OK some quick research shows the HDCP is coming from the Roku stick. Problem solved.

[dick_barton]

Re: JVC EM48FTR turns on quick but image takes time

Glad to see you got it sorted.