Home Theater Forum and Systems banner

1 - 17 of 17 Posts

·
Registered
Joined
·
9 Posts
Discussion Starter #1
I successfully repaired the convergence problem on my set. After repair I aligned the convergence and the picture was good. While going thru the cable menu I noticed that the left side of the tv, the lettering on the menu was misaligned. I went back in the convergence mode to try and repair the misaligment with no success. We continued watching the tv which had no real noticable problem while watching programs. The missalignment was mostly apparent while in the menu mode using the cable box. Not being satisfied I went back into the convergence mode to try and repair the unit and while I was adjusting the green grid, I got the extreme out of alignment lines, meaning it went way out of alignment then the picture went blank. Now all I get is the red power light in the front. I should have let well enought alone but that's a little late now.
 

·
Registered
Joined
·
9 Posts
Discussion Starter #3
I must of tried to do an extreme alignment, bringing in the edges and it must of driven the signal to high. Could I have damaged the convergence chips or blown a fuse?
 

·
Plain ole user
Joined
·
11,121 Posts
It is certainly possible. Any system adjusted to the extreme is subject to damage. It is difficult to comment and speculate, as I have never heard of anyone experiencing this.

As I point out in the convergence sticky, one should never continue adjusting when little or no effect is realized. You are likely driving the chips harder and harder, perhaps causing overheating or you may drive the convergence generator beyond its range.
 

·
Registered
Joined
·
9 Posts
Discussion Starter #5
If one or both of the convergence chips went bad would that cause the convergence to become missaligned or could it be possible when both fail the picture goes blank?
 

·
Registered
Joined
·
9 Posts
Discussion Starter #6
I checked the pico fuses on the board and they were good, do you recommend I replace the 2 convergence chips?
 

·
Registered
Joined
·
9 Posts
Discussion Starter #8
No sound, no picture, pc board leds inside set are on, front panel red indicator light is on, that's it.
 

·
Registered
Joined
·
9 Posts
Discussion Starter #10
I ordered two more convergence ics and replaced the ones that were in there and I got sound and a picture. The original ics must have shorted out and the tv shut down to prevent further damage. I went into the convergence mode for alignment and everything was pretty good except the horizontal green. The lines were good in the center but as it went to the top and bottom they were bowed too much to bring in. I am assuming that the green horizontal circuit still has a problem. I am going to check the resistors in the green horizontal circuit, would you know which ones they are?
 

·
Registered
Joined
·
9 Posts
Discussion Starter #11
Ok, tv is up and running again. The reason for the green horizontal lines being bowed was because something was shorting out R62 which is the resistor in the green horizontal circuit. I ended up changing the chip that controls the green horizontal circuit and resistor and all is well. I do still however have one horizontal green line that I can't not get straight on a couple of crosshatch squares near the bottom left. I have decided to live with it because it doesn't seem to have any effect on the picture.
 

·
Registered
Joined
·
4 Posts
Well after 12+ years my hitachi 43fdx01b took a break. my red vertical went all wavy and occilated/fluttered.
all other convergence stayed dead on. Never hearing of such an issue I attempted to adjust service convergence. did it a few times many years ago after moves.

I could not however adjust that red! it would spaz out. I did a dumb thing before investigating on the net and fiddled with the focus/screendrive- i believe i returned it back to original poss.

Long story short- I ordered the sanyo stk 394-160e (2x) and all six resistors. replaced all. (none of the resistors were off spec. turned tv on....red vertical was still wavy and spazy at top but not fluttering. I managed to adjust convergence near ballpark ;but was nowhere done when when poof image turned off!

Now set clicks on (red light in front) all leds on boards lit....but chirp sound every second coming from def power supply transformer area. red led on def supply also seems to pulse a bit. Pulled board out and rechecked everything again with magnifier lens- all looks good.
unplug 120v to def supply- sound stops, unplug all other harnesses from board except power from board - noise there.
Could I have another problem? after all unless I "stored" the bad red convergence why should it have looked like that? Did my chips blow? Did i push them too hard with the convergence adjustment? Do the 160s pull more power than the 110s?
I can get stk392-150 (STK392-150 NTE 7178 ) locally...shipping of 394-160e from states takes a week.
Am I better off with the 150s?

Any suggestions ? I really like this old 4X3 relic....but don't want to spend a fortune either.
there's no magic focus on this model so I can't hit the ballpark quick. am I better off to do it in stages?
my screendrive looks fine- should I start by lowering it first?

I guess I just don't understand what could be wrong or what happened...(especially since I hear about known issues of Horizontal output transistors etc. shorting power supplies) if this is even true?

Any suggestions/help would be apreciated. I trust what i've reed on this forum...you guys seem to have a bunch of repair experience.
 

·
Plain ole user
Joined
·
11,121 Posts
Pull the chips, check all of the fuses. If the set runs with the chips out and any bad fuses replaced you have a bad IC.
 

·
Registered
Joined
·
4 Posts
Yes, it was a bad chip.

Yesterday I pulled the board out. I figured the power supply was "rebooting" from a short over and over-hence the noise. (for lack of a better discription).

I checked a few values around the board; checked the power supply and rectifier bridge.All good. My main supp caps were discharged so I figured a short. I took a gander at switching out one of the 160s with one of the old 110......figured the set would at least light up if it was a shorted chip .
Through fuzzy logic: I chose to swap out the red ctrl 160. (50/50 chance of being right). after all i was taxing the red convergence when It blew- if that makes any sence. I never marked the 110s when I pulled them out...so I also had a 50/50 chance of putting in the good one.

The set turned on......but I chose the wrong 110! My red is spazzed out like before the repair....oh well...I was playing the odds!

Gonna swap the 110s for a test. If I can get motivated! If it works fine I'll get some 150s tomorrow...can't find 160s around here....only 150s. And after my experience with 160s....I don't trust my US supplier selling originals.
 

·
Registered
Joined
·
4 Posts
Good news! just finished swapping the 110s... All is sweet! took a while to adjust the covergence Since I mixed it up good the first time the chip blew ....but it is done.

Should I bother getting 150s? I am now running 1 160e and 1 of the old 110s. I know it's not ideal; or recomended. But i'm getting tired of pulling that board out.


On a side note: 2 of the anode silicone boots at the fb split (age). No arc or anything....I figure they are just dust boots to prevent arc tracing from contaminants entering towers. Is this right? How critical is this? Can I find these somewhere....a tv repair shop? Maybe similar in some scrap tv? ....
The casualties of war...
 

·
Registered
Joined
·
4 Posts
well that repair lasted about 20 minutes... and vertical red is off again. turned power off then on and puff. The resistors are all good. Seems a little to coincidental that its always red going. gonna have to check the whole circuit path for red amp. something must be off. Can the two chips being different cause any problems? i figure unlikely cause both H and V for red are on the same chip The power to both chips seems to come from the same supply path so i figure that shouldn't be the problem (spikes).
I'm using z9 (gc 10-8108). heat sink compound....it scored very high in tests done by overclockers etc. almost same as arctic silver.
I'm a bit stumped.... I picked up a 392-150 last friday (they only had one left ) but still havn't installed it. Im at the limit of the budget that i would like to spend on this old set. a new flat is cheap and takes up less realestate in the house.

From past experience....has anybody seen a similar recurring problem like this? any suggestions welcome. could the problem be somewhere else?
 

·
Plain ole user
Joined
·
11,121 Posts
Check the resistors and dc offset. Seen too much offset and trying to compensate with convergence correction do it. Could also just be bad chips, bad connection, or a bad yoke.
 
1 - 17 of 17 Posts
Top