EBR73712701 YSUS No Vsc

[mmartell]

Re: EBR73712701 YSUS No Vsc

Nah I think I probably killed it messing with the Ysus. All the ribbons look clean.

Going to pull the scan ic tomorrow to get a part number.

[freakaftr8]

Re: EBR73712701 YSUS No Vsc

OK cool. Just to confirm everything else is cool with your Ysus Usually I heat up the IC in carefully remove it until I measure no shorts then you can plug sustain board back in as long is there are no pins touching each other and power it up. You're going to have a black spot where the IC is reemoved however you should have your data drive back and you should have the relatively good looking picture minus the area that you removed.

[mmartell]

Re: EBR73712701 YSUS No Vsc

That's exactly what I'm going to do - thanks for the feedback.

And btw, not a single broken, "for parts" buffer on ebay to snag a scan ic from. wtf ?

[tom66]

Re: EBR73712701 YSUS No Vsc

The scan ICs are pretty universal parts, in a lot of cases you can use the same scan IC used in a previous generation if it's got the same number of pins.

[mmartell]

Re: EBR73712701 YSUS No Vsc

I don't think I have any buffer boards around here. I have a few Samsung scan ic's but they're from a 720p set. Probably just buy a used but working board.

[tom66]

Re: EBR73712701 YSUS No Vsc

720p and 1080p buffer ICs are often similar,

1080p sets have 12 sets of 96 channel ICs for >1080 lines (some are unused)
720p sets have 8 sets of 96 channel ICs for 768 lines

[mmartell]

Re: EBR73712701 YSUS No Vsc

Ya I went looking for the ic's I have and came up empty...

But I did remove the shorted ic cleanly and made sure there was no pin bridging and reinstalled it. The result is ambiguous. Same missing voltages and no prime/ no pic. I removed it and ran it again with only lower buffer and got the expected prime and garbage on the lower half presumably where osd is.

Not sure if that result is merely a peculiarity of this set. At least I hope so.

[mmartell]

Re: EBR73712701 YSUS No Vsc

Found a single FE3407F same package and looks to be the same electrically. The legs are all jimmied up though. Will probably pop right away but will attempt to straighten the legs and get it installed. Fun fun fun.

[freakaftr8]

Re: EBR73712701 YSUS No Vsc

You should be able to run that TV with the shorted ICs removed. Unless there are other shorted ICs on that top buffer board as well.

[mmartell]

Re: EBR73712701 YSUS No Vsc

I don't believe there are any more shorts. Will check again though.

[mmartell]

Re: EBR73712701 YSUS No Vsc

As long as the ysus is ok. I'm on the verge of ordering a replacement board anyhow.

[mmartell]

Re: EBR73712701 YSUS No Vsc

Is there any convention to locating Pin 1 on an ic with respect to the writing on it ? This FE3407F scan ic I have has no visible marking and web info is scant.

I believe it to be the bottom left when reading the chip info but of that I am not certain.

[mmartell]

Re: EBR73712701 YSUS No Vsc

Well that was fruitless. Absolutely no change. I have to wonder if there's still something wrong with the ysus. But why does having only the lower buffer connected produce a pic ?

If the problem is indeed the upper buffer board then I'm a little concerned that it's quite possible to buy a dud replacement without it showing signs of a short yet still not working.

[freakaftr8]

Re: EBR73712701 YSUS No Vsc

I suppose. Anything is possible. Also have you considered a short in the panel I know it's far fetched however my assumption is would be alleviated if you were to try to run the buffer without the panel connected to the buffer. I've done this before however only on Samsung's I'm not sure what the outcome would be on LG

[mmartell]

Re: EBR73712701 YSUS No Vsc

Worth a try before I spend money on a buffer I think

[mmartell]

Re: EBR73712701 YSUS No Vsc

Ran the set with the buffers installed but the upper buffer panel ribbons NOT plugged in. Same result - no raster and no Vsc/-Vy.

When I run with the lower buffer only I have good -Vy and garbage on the screen but no Vsc because the upper buffer is not installed.

So,
either I have something on the buffer failing under load.

Or,
something failing on the Ysus when Vsc attempts to come up.

Will sleep on it.

[freakaftr8]

Re: EBR73712701 YSUS No Vsc

Huh odd. Imho If you see anything on the screen you have to have Vscan coming out of that board. Can you post a picture of what you're seeing on the bottom half of the screen?

[mmartell]

Re: EBR73712701 YSUS No Vsc

I'm sure that's a No Signal or such box floating around. I've since read a few accounts where very similar or same symptoms were solved with a new upper buffer so I'm going all in.

[freakaftr8]

Re: EBR73712701 YSUS No Vsc

Looks like a new upper buffer will solve your issue. Thasts a normal picture when data even and odd signals are not reaching buffer.

[mmartell]

Re: EBR73712701 YSUS No Vsc

Update: after some misadventure with USPS and receipt of a "working" (shorted!) upper buffer I finally took possession of working upper and lower buffer set.

I think messing with the set led me to kill a probable good upper and definitely good lower. It's possible I could have got away with touching up the joints under the transformer. Ah well, working now...

Thanks for the help.