Trying to repair a bigscreen TV

Thread Starter

strantor

Joined Oct 3, 2010
6,782
...What do you have to hook up for a signal source........broadcast / cable / satellite / vcr ?? I ask this 'cuz the menu in your good picture is only an onboard feature of the unit, and comes up briefly when called for.....
Are you saying there is a difference between the menu and "X" signal source? I don't understand how that works. maybe I will be enlightened when I plug in my cable and it looks different from the menu.
 

PackratKing

Joined Jul 13, 2008
847
Are you saying there is a difference between the menu and "X" signal source? I don't understand how that works. maybe I will be enlightened when I plug in my cable and it looks different from the menu.
Yes.....the menu, when called up, lives in a ROM chip somewhere on the boards......How they make it interactive escapes me, tho' it's most likely some form of memory other than read only.........

Plug in a feed from a dvd...........you may be in for a pleasant surprise :p

You are right on the dust issue........dust + humidity wreaks havoc with some of the tinier voltages circulating in there.

Burned-in solid state electronics [ any item outlasting it's mfgr warranty ] are relatively bulletproof until they get wet or some other situation causes misdirected voltage spikes where they don't belong.

Always do the routine cleaning and inspection, and address discovered issues prior to firing any set up.

Funny thing here........When TV went irreversibly digital HD, I put my function generators etc. on mothballs, and have seen umpteen hundred 32 + inch sets, and potentially thousands of dollars go by the board, likely for real B.S. reasons...........
This thread has me seriously thinking of getting my feet wet again.
What-the-hey..........Ise retired, and one can only go fishing just so many times :D Nothing ventured............
 
Last edited:

Thread Starter

strantor

Joined Oct 3, 2010
6,782
Yes.....the menu, when called up, lives in a ROM chip somewhere on the boards......How they make it interactive escapes me, tho' it's most likely some form of memory other than read only.........

Plug in a feed from a dvd...........you may be in for a pleasant surprise :p

You are right on the dust issue........dust + humidity wreaks havoc with some of the tinier voltages circulating in there.

Burned-in solid state electronics [ any item outlasting it's mfgr warranty ] are relatively bulletproof until they get wet or some other situation causes misdirected voltage spikes where they don't belong
Yes, looking at the picture of my "good" result, it looks like the static in the background may still be pincusioned. I will find out in a few hours & post it up.
 
we had a sony do the same problem ours had a flash focus that was suposed to fix it however it did't the crt projector tubes may have a adjust ment slider on them. i think in my research i came acros a tube controler or convergince chip may be the problem
(i remember a litle about this tv but this was 6 months ago so i may be mistaken)
i am not sure but the projector tubes are crt posibly try a degausing wand. i would gues that the red tube is the offender.

(not resposible for any thiang that happens)
 

JJS1234

Joined May 26, 2011
41
Seems like their are alot of good tv fixin threads going on.

I would give some advise, I don't know if DLPs are worth fixing much as I have seen LCD (LEDs are like the same thing) are becoming the de-facto choice. However I have learned that (although you seem much more experienced than me) you should wear thick rubber gloves while prodding around when the board is plugged in :O and I just now learned that before you buy you should probably research the model # to see if their are parts available to what you believe is wrong.

Hope you fix it, as I have no idea how to fix them and just wanted to give a little advise to people who might think of doing the same as you or I.

Thanks :)

-JS
 

Kermit2

Joined Feb 5, 2010
4,162
If you do locate the problem 'area', the first thing to do is look at the electrolytic caps. Are there any IN that area and how do they look physically. If there is, it can be a good idea to replace them with GOOD ones. Not all new aluminum electrolytics are GOOD ones either. Spend the extra 10 or 50 cents for the name brand ones, and going up in DC working voltage is not a bad idea either. Replace 6.3 volt ones with 10 volt ones, etc. etc. etc. blah blah blah.

Good find. ;)
 

Thread Starter

strantor

Joined Oct 3, 2010
6,782
If you do locate the problem 'area', the first thing to do is look at the electrolytic caps. Are there any IN that area and how do they look physically. If there is, it can be a good idea to replace them with GOOD ones. Not all new aluminum electrolytics are GOOD ones either. Spend the extra 10 or 50 cents for the name brand ones, and going up in DC working voltage is not a bad idea either. Replace 6.3 volt ones with 10 volt ones, etc. etc. etc. blah blah blah.

Good find. ;)
Ah, caps. These folks seem to agree with you. I think I might have a refurbished TV on my hands before I hit the sack tonight.

Here's how the TV looks with cable video input:



It looks alright; not quite perfect convergence and too much red, but I can't get it to work long enough to tune it in. When I get home and replace CL230 I bet it will work though.

I had guests coming yesterday & I wanted to impress with my new TV. Didn't have time to clean out the dust ot anything else so i just replaced the fuse. they Stayed about 5 minutes too long. It stayed on about 20 min and then blew right before they left.
 

Thread Starter

strantor

Joined Oct 3, 2010
6,782
Ok Guys, I'm calling it. 7:00AM -6:00GMT 24JUNE11. TV is fixed - my first documented success at TV repair. I replaced the mentioned capacitor (cl230 - 100μF 100V) with a 100μF 200V capacitor salvaged from my other TV. Re-soldered a handful of joints that looked iffy, cleaned up. Turned it on and performed the convergence procedure, then watched all evening. let it run overnight and picture is still perfect in the morning. I would post a pic but my camera phone quality isn't good enough to make any distinction between now and the last pic I posted.

My Radioshack p.o.s. multimeter decided it wasn't in the mood for reading capacitance so I drove to Fry's electronics to test my capacitors with the display model Fluke. The 100μF 100V capacitor I removed wasn't puffy & tested out ok with the Fluke at Fry's: 105μF and resistance measured infinite - does that mean it was good?
 

tom66

Joined May 9, 2009
2,595
Ok Guys, I'm calling it. 7:00AM -6:00GMT 24JUNE11. TV is fixed - my first documented success at TV repair. I replaced the mentioned capacitor (cl230 - 100μF 100V) with a 100μF 200V capacitor salvaged from my other TV. Re-soldered a handful of joints that looked iffy, cleaned up. Turned it on and performed the convergence procedure, then watched all evening. let it run overnight and picture is still perfect in the morning. I would post a pic but my camera phone quality isn't good enough to make any distinction between now and the last pic I posted.

My Radioshack p.o.s. multimeter decided it wasn't in the mood for reading capacitance so I drove to Fry's electronics to test my capacitors with the display model Fluke. The 100μF 100V capacitor I removed wasn't puffy & tested out ok with the Fluke at Fry's: 105μF and resistance measured infinite - does that mean it was good?
I'd recommend against using capacitors found in old products, for two reasons:
- they tend to like a certain voltage after getting used to it - for example if that cap had 100V across it at most times, then it would complain if it were then put in a circuit using 150V.
- you have no idea how old the cap is and if it is on its way out.

A replacement cap is about $1, even for a high quality one. Keep one handy if the replacement goes.

Dead caps removed from my find, an LG 42LC46, tested just 5% below nominal rating, which has a 20% tolerance anyway; what really goes wrong is increasing ESR and increased leakage current. Resistance will only tell you leakage current and should be high, but leakage is usually tested at the nominal voltage, a multimeter will test at <0.5V.

A simple way to test a cap is to charge it up to the nominal voltage and watch how quickly it decays. After the multimeter test was good, I charged the caps up to 10V. One dropped very quickly to 8.5V and the other to 6.5V, both are not good signs.
 

Thread Starter

strantor

Joined Oct 3, 2010
6,782
I'd recommend against using capacitors found in old products, for two reasons:
- they tend to like a certain voltage after getting used to it - for example if that cap had 100V across it at most times, then it would complain if it were then put in a circuit using 150V.
- you have no idea how old the cap is and if it is on its way out.

A replacement cap is about $1, even for a high quality one. Keep one handy if the replacement goes.

Dead caps removed from my find, an LG 42LC46, tested just 5% below nominal rating, which has a 20% tolerance anyway; what really goes wrong is increasing ESR and increased leakage current. Resistance will only tell you leakage current and should be high, but leakage is usually tested at the nominal voltage, a multimeter will test at <0.5V.
So, I guess I'll test caps leakage at their nominal vlotage with a megger from now on

A simple way to test a cap is to charge it up to the nominal voltage and watch how quickly it decays. After the multimeter test was good, I charged the caps up to 10V. One dropped very quickly to 8.5V and the other to 6.5V, both are not good signs.
cool. is there a formula I can use to determine how long a cap of a given capacitance should hold it's nominal voltage? or is just -more than a few seconds- good enough?
 

PackratKing

Joined Jul 13, 2008
847
""Ok Guys, I'm calling it. 7:00AM -6:00GMT 24JUNE11. TV is fixed - my first documented success at TV repair.""
way to go! many more happy repeats !!!
 

Thread Starter

strantor

Joined Oct 3, 2010
6,782
""Ok Guys, I'm calling it. 7:00AM -6:00GMT 24JUNE11. TV is fixed - my first documented success at TV repair.""
way to go! many more happy repeats !!!
I got 2 more broken bigscreen T.V.s on the hook to go pick up after work. one JVC HD flat panel (dead) and another RCA projector (no sound + convergence & color issue). Guy wants me to pay for them though. I told him i'd go have a look and make an offer. I'm thinking the RCA might be easy - maybe a fuse or single blown component (or could be completely annhilated); the RCA sounds like a pain. What do you think is a reasonable offer for the pair (assuming they're both as big as the one I just finished)?

BTW packratking, i'm getting leads off craigslist. http://houston.craigslist.org/wan/2450202036.html
 

tom66

Joined May 9, 2009
2,595
So, I guess I'll test caps leakage at their nominal vlotage with a megger from now on


cool. is there a formula I can use to determine how long a cap of a given capacitance should hold it's nominal voltage? or is just -more than a few seconds- good enough?
A good cap will hold a nominal voltage within 10% for several minutes, if not longer.

I got 2 more broken bigscreen T.V.s on the hook to go pick up after work. one JVC HD flat panel (dead) and another RCA projector (no sound + convergence & color issue). Guy wants me to pay for them though. I told him i'd go have a look and make an offer. I'm thinking the RCA might be easy - maybe a fuse or single blown component (or could be completely annhilated); the RCA sounds like a pain. What do you think is a reasonable offer for the pair (assuming they're both as big as the one I just finished)?

BTW packratking, i'm getting leads off craigslist. http://houston.craigslist.org/wan/2450202036.html
I'd pay no more than $30 each for them. Worst case, look at the price they are going for on eBay. No luck? Just sell it, you might even make a profit on selling them on.

http://shop.ebay.co.uk/i.html?_from...1313&_nkw=broken+tv&_sacat=See-All-Categories

This one with a completely wrecked screen is going for almost $35!

http://cgi.ebay.co.uk/PANASONIC-37-...tronics_Video_Televisions&hash=item43a7ee7de9

I'd never buy anything with a broken LCD/PDP; not worth repairing them.
 

R!f@@

Joined Apr 2, 2009
9,918
RIFAA you were determined not befriend me until i fixed something eh? I see how you are lol
U proved ur worthy to be my disciple :cool:.
and u are hanging around here too.

U did what a good tech should do. Find the fault and didn't screw around and inside, literally
 

Thread Starter

strantor

Joined Oct 3, 2010
6,782
I bet you guys thought this thread was at an end didn't you? well... Here you go:


I got another RCA exact same model as the one I just fixed, plus this 400lb mammoth mitsubishi TV from the early 90's.



The giant mitsubishi on the left, the guy said "All I know about it is that I used to watch it when I was a kid."

The RCA, he said his kid crammed a few dozen CDs through all the slots/openings in the front, then the sound stopped working. Later his kid ripped the digital cable jack out of the back and bent the analog one over. TV repair man cam in and ripped it all apart, then qouted the guy 500$ to fix it. thats when he called me. Sadly, the JVC DLP TV was spoken for by a family member by the time I got there.

pics of the RCA guts:










I'd pay no more than $30 each for them. Worst case, look at the price they are going for on eBay. No luck? Just sell it, you might even make a profit on selling them on.
Well, tom, I broke you budget a little. I paid 80$ for the pair.

Funny thing, on the way home with the TVs in the back, a woman pulls up next to me in the mcdonald's drive-thru and asks me if I want another one - JUST LIKE THE RCA, same model! that will be 3 RCA's same model. she said it's dead.
 
Top