Sony 34XBR800 - Screen goes bright red then off !!

Its most likely the picture tube that shorting. Some times (and I say SOMETIMES) this can be solved by tapping gently on the neck of the CRT with the TV closed (or open if u know what u're doing). This happens sometimes because the heater element while burning released conductive metal flakes and shorted the emitters to the heater element. Tapping on the tube can release those flakes and remove the short. BUT DO NOT TAP TOO HARD! YOU WILL BREAK THE NECK OF THE CRT AND REGRET IT FOREVER! Gentle and frequent taps taps are OK. This may solve your problem... so it's the first thing to try.

Another possiblility is the CRT video driver IC (TDA6120Q IC9001 On the CX board(the one on the neck of the CRT) for the red being short.. This has happened in some Hitachi TV's and can be the cause of the red video signal and shutdown. Try replacing it if tapping on the tube has no effect whatsoever.
Good luck!

This is my first post on this forum. I have the same issues on my TV and thought I should add to the discussion.

I was also about to give up on my KV-34XBR800 (purchased 3/2003). A couple of months ago, my set started having the "red burst" with the set shutting down and the standby LED blinking 7 times. I replaced IC6501 and IC8002 first during 2008 to resolve a 5-blink (?) and shutdown issue, and again this year (2011) in an attempt to resolve this red burst / 7-blink issue. In addition to replacing the ICs, I also replaced the large caps (C6590 and C6503) on the D board and a blown fuse on the A board. None of these fixed the issue (although replacing the blown fuse allowed me to turn the set on).

My co-worker suggested reflowing the solder joints at the flyback transformer on the D board and at the picture tube pins on the CX board. Just for good measure, I also touched up a few solder joints on the W board. The first 2 times I did this I saw some improvement but the red burst / 7-blink issue eventually returned. I tried again this past weekend (5 days ago), only on the flyback transformer solder joints (which I did only the first time) and the set has been working fine since. However, tonight I saw the color briefly shift greenish, then reddish, then back to normal. I also see that my horizontal convergence is off and I am now trying to figure out how to correct this.

At this point I hope to adjust the convergence (if I figure out how) then donate the set to charity, if it is still working. If the red burst returns, I'm told that it is a picture tube problem and is not worth replacing. In that case, I'll have it recycled.

I hope this helps! Good luck on your repair.

10-16-2011 Update: Unfortunately the red burst returned, so it appears that the problem is not with the solder joints. Yesterday I removed the back and the CX board and tried tapping on the CRT neck, as suggested by neccrttv in post #2 above, and will see if this resolves the red burst issue over the next week or so. It is possible that working on the set during prior attempts jostled the CRT enough that it caused it to work for a short period, usually a few days. I found an excellent reference (http://www.repairfaq.org/sam/crtfaq.htm#crtsht) explaining heater to cathode shorts in CRTs due to metal flakes and how this might cause the red burst. Failing this, I will try neccrttv's other suggestion of replacing the red video driver IC (IC9001) on the CX board.

Regarding the convergence issue, I was able to easily correct the dynamic convergence using the service menu and adjusting the appropriate D_CONV parameters, particularly CADJ. There is an excellent thread by KenTech ("THE SONY SERVICE CODES - Articles, Comments, Discoveries") that shows how to do this and other adjustments for various Sony sets. I was also able to adjust the color and reduce the "red push" on my set, which has been bugging me for years. This AVS Forum is truly a great place for learning to repair and maximizing the capabilities of my TV.

My KV-34XBR800 still has the "red burst" with the 7 blinks on the standby LED, even after I tried tapping the CRT neck several times. I tried this proposed fix twice over 2 weekends and each time the "red burst" (or early signs of it) returned within a week.

When I removed the CX board from the CRT 2 weeks ago I noticed that the contacts on the CRT socket and the CRT pins were a little oxidized. So last weekend I cleaned the pins with a contact cleaner/lubricant, in addition to tapping the tube. Unfortunately, this didn't seem to have much effect, and by the end of the week the red burst and 7-blink issues returned.

Towards the end of this past week I started seeing signs that the red burst was returning. I would get a brief flash of red or a few red lines, but not the entire screen and no shutdown. Then I would bump the TV with my palm and would see one or two partial red lines appearing in the picture. This made me think that I had a CRT short, or more specifically a heater-cathode (H-K) short, instead of a bad red video driver IC. This was not good since I wasn't sure how to fix a H-K short, or even if it could be corrected.

Nonetheless, today (Saturday 10/30) I replaced the red video driver IC on the CX board (IC9001, Philips part number TDA6120Q/N2/S1). The thermal compound from the original IC/heatsink was still creamy so I re-used it. I managed to desolder the IC without disturbing the surface mounted components near some of the IC pins. I also tried to desolder the aluminum heat sink onto which the IC was mounted but was unable to do so, possibly because they were riveted to the PCB (?). This meant that I had to remove the IC from the heatsink while the heatsink was still attached to the PCB. This isn't a big deal for the red video driver IC, but might be more difficult if the green or blue video driver ICs have to be replaced. For good measure, I also gave the CRT neck a few good taps before replacing the CX board.

After replacing the IC, my family watched TV and played video games continuously for about 8 hours. So far, so good. Bumping the TV with my palm did not produce any of the prior effects. I'll know in a week or two if the problem is resolved, and will post an update then.

So it appears that replacing the red video driver IC on the CX board (IC9001, Philips part number TDA6120Q/N2/S1) resolved the red burst and 7-blink issues on my KV-34XBR800. The IC was replaced just over 2 weeks ago and I haven't had the issues return yet.

This was after several months of trying different things, including: replacing ICs IC6501 and IC8002 and capacitors C6590 and C6503 on the D board, replacing a blown fuse on the A board, reflowing the solder joints at several locations (particularly at the flyback transformer and at the CRT socket pins), applying a contact cleaner/lubricant at the CRT tube pins and connector contacts, and tapping the CRT neck multiple times over several weeks.

It is very possible that replacing the IC alone did not resolve the problem, that it was in combination with something else I did that corrected the issues. I also thought it was odd that the IC failed in a way that bumping the set caused red lines to appear, or that it sometimes took up to a week after I tried something before the issues reappeared.

At this point I am just glad that the set is working. I still have plans to give it to a charity, but probably not until I save up enough for a suitable replacement.

Thanks again to this AVS forum for all the help in resolving this issue, particularly to member neccrttv for the tip on replacing the red video driver IC.

Snevig - thanks for the parts numbers!


My set would come on for anywhere form 5 seconds to 10 minutes then shut off. I replaced the red IC this evening and so far it's been running for an hour with no hint of red screen.

My cousin replace the two chips from the earlier issue but since he lives a couple hours away I though I would give it a try. Granted my solder joints aren't as nice as his (can't tell his apart from the factory ones) it is working!

Thanks again!!

Glad to see this was only the TDA6120Q acting up. Glad u were able to repair your TV.

These IC's go bad in many TV's.. they are used as CRT board video drivers in Sony, Toshiba and many many other sets. Often people diagnose a short tube while the cause is the TDA6120Q.

This is a pic of the CX board. Of course i cant say if its the same as yours(it should be exactly the same cause your chassis is DA-4 and its exactly like this in the SM).. but whats important is that this board is located on the neck of the picture tube.


The ic named IC9001 is the one you must change. Its the one to the left on this pic. You have to desolder it.. it has 13 pins if i remember correctly. Once unsoldered.. u remove the screws on the IC itself, and remove the defective ic.
Verify that all holes for the pins are free and then insert the new IC through the clean holes and resolder it back on. Make sure theres enough thermal compound on the ic. Either take it from the old ic or if theres still on the heat sink, use that paste.

For where u can find it.. well many places sell it. Even Amazon sells it. Search for TDA6120Q. Theres Global Electronics in Canada... etc. lots of places sell it and its usually under 10$.

Great picture neccrttv! In the photo the red video IC (IC9001, 13 pins) is hidden from view, but is mounted on the outer (left) surface of the left heat sink. I'm no de-soldering expert and had to be very careful to not de-solder the small surface mount components near some of the pins when I de-soldered the IC.

I ordered the Philips TDA6120Q/N2/S1 IC from B&D Enterprises (bdent.com) for US$10.59. I ordered 2 so that I would have a spare. I also ordered some thermal compound but ended up reusing the stuff that was on the old IC and heat sink.

My TV is working great, except I now occasionally see a brief red flash on only a small portion of the screen. It doesn't happen often (at most once or twice a day) and it doesn't cause the set to shut down. I suspect there is still an underlying problem, but not severe enough to cause any real problems (yet).

Any ideas what causes this, and could this cause the IC to fail again?

The underlying cause of the video driver TDA6120Q going bad is due to the picture tube having a momentary short. It is always possible u will see flashes of red (or any other color) still because the IC gave away because of these flashes . But what i can say is that it can last a long time, even with the flashes. These sony tubes are very touchy.. its the construction of them that is very bad. I've seen some tubes last a couple years after having the TDA going out. Occasional flashes are ok as long as it doesnt shut down. But what i can say is that when it does shutdown, most of the time it takes the TDA6120Q with it.

And yeah, you have to be careful desoldering these IC's.. its very easy to accidentally touch the surface mount resistors and capacitors and lose them... they are very small, and u won't be able to determine their value unless you have a service manual.

Any suggestions on how to repair or "discourage" the picture tube from having these momentary shorts (aside from not using it)? Or are all Sony tubes in the KV34XBR800 and similar sets doomed to fail in this way?

It depends.. if its a short from the cathodes to the heater.. the best way is to isolate the heater from the rest of the circuit. We do that often here but its kinda of a secret
What we do is that we cut the print to the heater and supply the heater from a wire that does a couple of loops around the flyback transformers coil. Usually one or two loops generates enough voltage by static discharge of the electric field to light up the heater to its normal voltage.. useful in lots of cases.

Im not gonna go too much in detail on this, its pretty dangerous but i can say it has saved many TV's with a Heater Cathode short.

Congrats to Tendoboy for a successful repair!

Unfortunately I have some not so good news. My KV34XBR800 started showing brief red flashes a couple of weeks ago, and this week the red burst with shutdown and 7-blinks returned. After the 1st time this happened, I unplugged the set, then tried it again and it happened again (not sure how long; my wife was watching).

The 2nd time it failed was a few days ago. Today I removed the back and CX board then tapped the tube neck with a screwdriver handle.

I checked for shorts between the pins on the tube and found them only between G1-1, G1-2, G1-3 (less than 1 ohm) and between H1, H2 (less than 5 ohms). I think these pins are normally shorted, so my short must be intermittent.

After I replaced the CX board and the back cover, I turned on the set and everything worked fine for the entire night. I'll see how long this fix will last.

My plan is to tap the tube neck when I start to see the brief red flashes so that I can prevent the red video driver IC from getting damaged by the intermittent shorts.

Is anyone else having a recurrence of this problem?

I just replaced IC9001 (red video driver, IC TDA6120Q/N2/S1) for the 2nd time, and my KV34XBR800 appears to be working once again. The 1st time I replaced IC9001 was early November 2011 (see my posts above). About 3 months later the red burst with shutdown and 7-blinks returned.

I was usually able to get the TV to work again by removing the cover and CX board then gently tapping the tube neck with a screwdriver handle. I typically tapped the tube radially in different directions for about 10 minutes while I listened for the "ringing" of the tube internals, then checked for shorts with a multimeter before I replaced everything.

When I first did this after replacing IC9001 the 1st time, the TV worked for about a month. Over time, however, the time between tapping the tube neck and having the red burst/shutdown/7-blinks issue return reduced from a month to a couple of weeks, then to days, then finally to hours. When I finally resigned to de-soldering and replacing IC9001 for the 2nd time, the time between tapping and failure was less than 1 hour.

I believe I've done the repairs that I'm able to do with this TV, and now it's time to move on. I suspect it is only a matter of time before the problem will return again, so I am on the hunt for a replacement. It's a shame that I will have to give up this set as I am quite pleased with the picture and sound quality. On the other hand, this TV is huge and it will be nice to replace it with a more modern and space-saving flat panel (larger screen size, of course).

Thanks to this AVS Forum and other forums I was able to extend the life of this TV several years at minimal cost. Special thanks to neccrttv for the advice on tube tapping, the red video driver IC replacement, and other suggestions.

Its a shame.... those Sony tubes arent what they were..... too many of these failing. Ive recently worked on a 1979 Zenith. Its not even cable compatible lol but the tube is in perfect shape even after 33 years of constant 2-3 hours of use each day. It doesnt even shear when the contrast is at the maximum and precision is still perfect. The woman noticed that her LCD TV (a horrible Toshiba on SD cable mind you) had a far worse image than her 33 year old TV.... and the worse of it all is that the Zenith has a brighter image and can be viewed at any angle.

I do hope you find a good replacement.... id always suggest finding a good sized PC monitor (35/36") but with plasma TV's nowaday im sure you will find an adequate replacement.

Thank you guys for all the info. I'm having a bright green and then off within 5 secs. Here's a video showing a similar problem, I would appreciate any input, Thank!

http://www.youtube.com/watch?v=iM5vZu7b-E0
Edited by iTQAN - 9/17/12 at 6:50am

.Most likely the same thing as posted before except that its probably the green crt video driver thats gone bad. Refer to previous posts but it would be IC9002 (middle one) that you have to replace. It would also be a TDA6120Q.

Thank you neccrttv, I'll give it a try and keep you guys posted.

I got the monitor fixed by replacing the RED and the GREEN TDA6120Q. Also I found a faulty small carbon 2.9 ohm resistor between the input of the 200 volts and pin 10 of TDA6120Q. As soon as I replaced the resistor with a good one the unit came back to life. Thank you everyone for the help.

I am currently repairing my in-law's 34XBR800 that had the identical problem posted by the orginal poster. Much to my chagrin, replacing the TDA6120Q video amplifier did not fix my problem. The root cause however turned out to be real easy to repair; bad solder joint for the red drive on the CN9001 connector, pins 1 and 2. Wish I'd done a few more minutes worth of troubleshooting, I'd have fixed this thing a week sooner instead of waiting for parts and it would have been free.

Now to haul this beast back to the in-law's house...

another thing to try if you think it's a heater to cathode short is unplug CRT board noting which are heater and cathode pins.what you do is setup a 100 watt mains filament bulb in a holder and connect it in series between both heater pins that have to be connected together and the shorted cathode pin of the tube.plug into mains and turn on.be careful don't touch anything while its on.bulb will light if there's a short and go off if it burns the short open.if bulb goes off turn off at mains .plug crt back on to tube reassemble and try.
Edited by blownvp - 1/2/13 at 6:43am

Sony KV-35XBR48
I had similar problem, but with the green screen with scanning lines.
As the TV warmed up, there were consistantly worse flashes of green.
Sometimes after 10 minutes, it would stop, and tv back to normal.
Other times TV would shut down, by itself.
After touching up all solder joints on pcboard, on back of tube,
and later tapping picture tube neck,
I did some research here and another site.
I finally figured out it was the famous Cathode to Heater short.
Was getting tired of knocking the tube neck with a wooden stick every few days.
Having had some knowledge of electronics, it was time to do major surgery.
Before I modified anything, using my cheap digital meter,
I measured the ac heater voltages, which were wacky,
depending on which polarity I connected probes.
Took note of both measurements. Unplugged TV power cord.
Then I cut the heater traces on the pcb, so the original heater power was disconnected.
I then wound insulated wire two turns through the FlyBack ferrite Transformer.
It's really three turns if counted from the outside of core.
I soldered one end of this new winding to the .5 ohm resistor,
(that was there already going to one heater pin),
and soldered the other end to other heater pin.
Double checked my work. Took a deep breath, plugged in tv and turned on.

Amazing. No sparks, no blowups. I carefully measured heater voltage.
It was about .5 volts less than original, but picture good.
I decided to add one more turn on FBT.
Did it. Picture is as good as before, in fact even better.
There are no more flashes of green, and the extra 15 % voltage boost to the heaters,
has made white lettering sharper, and brighter. It may shorten the picture tube life somewhat,
but after 16 years, even one or more years better than nothing.
Very happy. Thanks neccrttv!

Me back again.
Still no flashes. I do notice one thing about the dynamics of the picture.
Does not seem to be regulated anymore.
I guess, because of the floating heater voltage.
If there is a white background picture all over, as in ads,
the whole screen will be light grey, instead of white.
As the picture changes to regular indoor/outdoor movie shots, it looks normal,
if not more dynamic,(more whites and blacks).
Anyway, can't complain too much.
Tube tv's look better to me, at least for lower resolution 4\3 ratio.

I eventually will buy a replacement LCD tv, to replace this tube tv.
Too bad LCD can't get rid of ugly color tint\ washed out changes, viewing from sides.
Yes LCD's have a sweet spot for price, and a sweet spot for optimum viewing:(

I am curious why you chose to do that kind of repair instead of swapping out the TDA6120Q chip? Looks like your issue is the the same except you change the green one. There is the red , green and blue accompanied by the heatsink. I just did this repair on my 34xbr960 and it runs flawlessly again. Make sure you do a solid solder on each pin if you ever want to try out this route. Good luck.