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TELEFUNKEN PAL COLOR 2560 white horizontal lines on bright screen

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Megatron
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Dec 12, 2014, 8:58 PM

Post #51 of 60 (1610 views)
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Re: [jts1957] TELEFUNKEN PAL COLOR 2560 white horizontal lines on bright screen [In reply to]	Can't Post

I Know, I just found on power supply triger burned D538 zener diode, bad capacitor C107. I forgot to mention on chronology that I changed broken PTC resistor R241 on demagnetisator circuit. This is just the begining.

I'll make report when I finish complete inspection.

Megatron
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Dec 19, 2014, 6:54 AM

Post #52 of 60 (1582 views)
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Re: [Megatron] TELEFUNKEN PAL COLOR 2560 white horizontal lines on bright screen [In reply to]	Can't Post

Checked all electronic elements on motherboard and found nothing more then these two elements from previous post.
C107 repleaced, D538 I have to find on my sore of scrap PCB.

Today I have to go on journey so I don't know when I'll come back and resume repair.

Megatron
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Feb 11, 2015, 9:45 PM

Post #53 of 60 (1517 views)
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Re: [Megatron] TELEFUNKEN PAL COLOR 2560 white horizontal lines on bright screen [In reply to]	Can't Post

I was on journey almost two months and today I have finished repair. I have to do just small picture adjustments.

The zener diode D538 is just fine. I bought the new zener diode 2V0, tested and I thought that the seller sold me invalid zener diode. The feature of diode 2V0 is that it has high resistace and usualy on analog tester x1ohm where on all diodes resistance is droping to zero, on the 2V0 diode the instrument needle was not moving and showing the infinite resistance. For diode 2V0 testing because of high resistance, you have to put on tester on x1kohm range where the instrument current is higher and there will the needle start moving and droping to 0ohm.

For example on zener diode 2V4 is normal reading on x1ohm instrument range.

These are the readings on digital diode tester:
old 2V0 "good" 1890mV
new 2V0 "good" 1814mV
2V4 "good" 690mV

So I puted an old 2V0 zener diode D538 back to PCB because it is fine.

I didn't have any idea what to do further because I tested whole elements, so i tried to put back an old original video chip TDA 3562 A and the picture finaly become normal without retreace lines.
On video chip RGB output pins 13,15,17 finaly have 2V instead 0,8V on faulty chip.

On RGB cable from video card output to CRT plate input the voltage also droped from to high 190-200V to normal 135-170V.
I measured on RGB cable:
Red: 160V
Green: 167V
Blue: 163V

So the conclusion is that that the cold solders caused all that problems and when I started touching, moving and straining the PCB the weak cold solders became wors and the television start blinking and tilting and burned the new video chip TDA 3562A. Naw all solders are renew with lifetime warranty.

Many thanks for help especialy for expert @jts1957. Thank you Ron M. too. Smile

Here are some pictures of Telefunken screen now, just need for some small adjustments because the picture is not in center entirely and have black strip on left side:

[URL=http://www.igreklik.com/slike/viewer.php?file=70808065834244426442.jpg&file_imgur=lyS8PRi.jpg]

[URL=http://www.igreklik.com/slike/viewer.php?file=00535293248842223549.jpg&file_imgur=FqAzq8H.jpg]

Megatron
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Feb 11, 2015, 9:47 PM

Post #54 of 60 (1515 views)
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Re: [Megatron] TELEFUNKEN PAL COLOR 2560 white horizontal lines on bright screen [In reply to]	Can't Post

The picture link once again:

[URL=http://www.igreklik.com/slike/]

[URL=http://www.igreklik.com/slike/]

(This post was edited by Megatron on Feb 11, 2015, 9:52 PM)

jts1957
Veteran

Feb 11, 2015, 10:13 PM

Post #55 of 60 (1509 views)
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Re: [Megatron] TELEFUNKEN PAL COLOR 2560 white horizontal lines on bright screen [In reply to]	Can't Post

Glad to see that things got sorted. Smile

-------------------------
Location: Far, Far Away

Megatron
User

Feb 11, 2015, 11:28 PM

Post #56 of 60 (1505 views)
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Re: [jts1957] TELEFUNKEN PAL COLOR 2560 white horizontal lines on bright screen [In reply to]	Can't Post

I was so despered that I couldn't win 30 year old televizion, but I didn't give it up.

Thanks again! Smile

(This post was edited by Megatron on Feb 14, 2015, 8:46 PM)

Megatron
User

Jun 15, 2018, 4:17 PM

Post #57 of 60 (834 views)
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Re: [Megatron] TELEFUNKEN PAL COLOR 2560 white horizontal lines on bright screen [In reply to]	Can't Post

New problem with the same TV.
Now the CRT screen is Black. I can't get even snow on screen, it is always black whether there is the signal or not. The sound is perfect, remote control works perfect, but no picture. The only picture I get is 1/2 centimeter redish horisontal line in upper edge of screen and small white spot in upper left part of the sreen when the signal somes from scart.

Here are some pictures in the dark:

https://ibb.co/k5pR4d
https://ibb.co/cvFuqJ

The gun is glowing in the dark:
https://ibb.co/eFX2cy

I checked all voltages and are fine except on video chip IC401 TDA3562A on output RGB pins 13, 15, 17 instead 2,2V I measured 1,0V and on output RGB connector ST3031 instead 135-170V I have measured 190V.

The video matrix chip IC401 TDA3562A is warm I would say 60-70�C when I put finger.

On resistor R309 to pin 6 connector ST3091 should be 12V, but I read some mV and on this pin is nothing connected. This connector is right next to vertical chip IC431 TDA1870.

Here is the datasheet:
http://i.imgur.com/saTeiMq.jpg

Yesterday night the picture first time disappeared and in the morning appeared once and when I turned TV off and again on the picture doesn't want to appear and it is the same as on pictures attached.

What could be the issue?

(This post was edited by Megatron on Jun 20, 2018, 6:09 PM)

Megatron
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Jun 20, 2018, 6:16 PM

Post #58 of 60 (823 views)
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Re: [Megatron] TELEFUNKEN PAL COLOR 2560 white horizontal lines on bright screen [In reply to]	Can't Post

On video chip IC401 TDA3562A on pin 18 I have measured some weard high pikes on oscilloscope. I don't Know is it normal.

Megatron
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Jun 22, 2018, 1:49 PM

Post #59 of 60 (811 views)
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Re: [Megatron] TELEFUNKEN PAL COLOR 2560 white horizontal lines on bright screen [In reply to]	Can't Post

On round cathode connector I have this voltages:
R 195,2V
G 192,4V
B 188,4V

When I disconnect RGB cable from connector ST3031 on the same round cathode connector I have this voltages:
R 43,7V
G 45,6V
B 45,3V

On RGB cable on connector ST3031 where datasheet say it must be voltages within 135V-170V, I have measured:
R 194,3V
G 191,7V
B 188,5V

When I disconnect RGB cable from connector ST3031, I have this voltages on connector ST3031:
R195,1V
G192,1V
B188,5V

Turning G2 trimmer potentiometer from min to max I get nothing on picture except luminate and deluminate upper edge of screen 0,5-1cm as on picture:
https://ibb.co/nDFSpo

Cathode guns are luminating:
https://ibb.co/eLzj28

The voltages on videomatrix chip IC401 TDA3562A output RGB pins 13,15,17 should be 2,2V and I have measured 1,0V. When I remove the chip IC401 TDA3562A from the board on the RGB pins output 13,15,17 I have measured 3,1V. With removed chip IC401 TDA3562A on RGB connector cable ST3031 I finaly have normal voltages within 135-170V ,but black screen:
R 141,8V
G 141,6V
B 141,8V

Megatron
User

Aug 28, 2018, 8:00 PM

Post #60 of 60 (734 views)
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Re: [Megatron] TELEFUNKEN PAL COLOR 2560 white horizontal lines on bright screen [In reply to]	Can't Post

Problem with black screen solved. The problem was on cheramic capacitor C386 10nF 2000V on CRT board next to SCREEN GREED (G2) trimmer. When testing with capacitance meter it normaly shows 10nF as it should be, but when comes high voltage it is shorted.

I had to buy leakage tester which goes from 0V up to 1500V/2000V and loading the capacitor it starts to leaking and shorting somewhere about 100V which caused Black screen.

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