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Crumbtrail TV Forums: TV Equipment: TV Repair Forum:
TELEFUNKEN PAL COLOR 2560 white horizontal lines on bright screen

 

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Megatron
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Nov 27, 2014, 2:23 AM

Post #1 of 60 (6404 views)
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TELEFUNKEN PAL COLOR 2560 white horizontal lines on bright screen Can't Post

Regards,

I am trying to repair an old Telefunken TV with white horizontal lines on bright screen.
http://www.zaslike.com/files/z40rb2mt3ba4xea0buc1.jpg

I found the problem with voltage on RGB signal output cabel from video board to CRT tube board. On datasheet it has to be 135-170V and I measured 87V only. When I disconnect this RGB signal cabel and measured again on video output bord side I measured the same 87V on all three colours and on CRT tube board RGB input measured 111V on all three colours.

Video bord supply is fine and CRT bord supply is fine to. I measured on G2 460V and I don't know is that fine for 72cm CRT screen.

Where is the problem, I assume on video bord or on videoboard IC TDA3562A or maybe I am wrong.

What do you think?
Thank you


(This post was edited by Megatron on Nov 27, 2014, 2:30 AM)



jts1957
Veteran


Nov 27, 2014, 3:28 AM

Post #2 of 60 (6392 views)
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Re: [Megatron] TELEFUNKEN PAL COLOR 2560 white horizontal lines on bright screen [In reply to] Can't Post

TDA3562A PAL/NTSC ONE-CHIP DECODER
RGB - OUTPUTS (Pins 13, 15, 17) = Minimum 10.7 Volts - Maximum 11.3 Volts?


Quote
On datasheet it has to be 135-170V and I measured 87V only.

What datasheet?

Source for schematic?


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Location: Far, Far Away


Megatron
User

Nov 27, 2014, 3:54 AM

Post #3 of 60 (6389 views)
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Re: [jts1957] TELEFUNKEN PAL COLOR 2560 white horizontal lines on bright screen [In reply to] Can't Post

Datasheet chassis 615 C2 Telefunken <br> <br>I'll scann the schematics tomorow in the shop and put them on the web. My scanner is to small, it would be fragments of the sheet. <br>

Here is on the page RGB 135-170V and I misured 87V only:

http://www.highqualitymanuals.com/Telefunken-Chassis/615-C2-Service-Manual-p-12197.html


(This post was edited by Megatron on Nov 27, 2014, 4:02 AM)


Megatron
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Nov 27, 2014, 10:32 PM

Post #4 of 60 (6369 views)
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Re: [Megatron] TELEFUNKEN PAL COLOR 2560 white horizontal lines on bright screen [In reply to] Can't Post

I measured the output pins 13,15,17 on video TDA3562A and they all have 0,8V on each.

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


(This post was edited by Megatron on Nov 27, 2014, 10:39 PM)


jts1957
Veteran


Nov 28, 2014, 2:50 AM

Post #5 of 60 (6355 views)
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Re: [Megatron] TELEFUNKEN PAL COLOR 2560 white horizontal lines on bright screen [In reply to] Can't Post

Does bright screen dim down when Screen control is adjusted? Does 87 Volts vary with screen control setting?
What is being used as a signal? IF aerial/tuner on a active station, Is there correct audio?


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Location: Far, Far Away

(This post was edited by jts1957 on Nov 28, 2014, 2:53 AM)


Megatron
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Nov 28, 2014, 3:03 AM

Post #6 of 60 (6351 views)
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Re: [jts1957] TELEFUNKEN PAL COLOR 2560 white horizontal lines on bright screen [In reply to] Can't Post

Audio is perfect. <br>When you turn down voltage on G2 trimer the picture become dark still with lines, no changes. <br> <br>One more thing is hapening, when I switch off TV there is a violet spot on the screen few minutes after which lit in the dark room. This spot is not in center of the screen, it is a little bit left down and it is about one inch diameter. <br>

Doesn't mater with signal or without is the same situation, audio is perfect.


(This post was edited by Megatron on Nov 28, 2014, 3:05 AM)


jts1957
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Nov 28, 2014, 4:50 AM

Post #7 of 60 (6346 views)
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Re: [Megatron] TELEFUNKEN PAL COLOR 2560 white horizontal lines on bright screen [In reply to] Can't Post

With the screen turned down to a reasonable level, can ANY trace of video from the tuner or a SCART source be discerned? Also, do any on screen graphics (OSD) work?

You forgot to say if the 87 volts varies or stays the same at all settings of the G2 control.

Besides a DVM, what other test equipment do you have available?


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Location: Far, Far Away


Megatron
User

Nov 28, 2014, 2:12 PM

Post #8 of 60 (6340 views)
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Re: [jts1957] TELEFUNKEN PAL COLOR 2560 white horizontal lines on bright screen [In reply to] Can't Post

When I rotate the G2 trimer from minimum to maximum the voltage on RGB cable varies from 86-89V. When the voltage is on 88-89 the screen is starting blinking which shows in moment of blinking vertical wide white line with not streigh edges, fluffy. It looks like the screen is starting tilting of overpower. When the TV is turned on for long time lets say 20 minutes it also starts blinking the same way.
When you rotate down the G2 trimer you just dimm the picture (horizontal white lines) to the dark and the screen is full black and you can't get any traces of the picture signal on the screen. I can't get any picture signal traces when rotating G2 trimer. With rotating G2 trimer I am just dimming or undimming the screen with horizontal lines. Nothing comes on the screen of the picture signal, nothing, just audio have. Whether is signal on scart or not is the same situation when rotating G2 trimer always the same on RGB cable voltage 86-89V.

I do not have anything except digital and analog multimeter.


(This post was edited by Megatron on Nov 28, 2014, 2:40 PM)


jts1957
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Nov 28, 2014, 7:56 PM

Post #9 of 60 (6330 views)
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Re: [Megatron] TELEFUNKEN PAL COLOR 2560 white horizontal lines on bright screen [In reply to] Can't Post

Pin 1 of IC401 = 12 Volts?


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Location: Far, Far Away


Megatron
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Nov 28, 2014, 8:52 PM

Post #10 of 60 (6324 views)
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Re: [jts1957] TELEFUNKEN PAL COLOR 2560 white horizontal lines on bright screen [In reply to] Can't Post

Yes, 12V (11,82V)


jts1957
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Nov 28, 2014, 9:46 PM

Post #11 of 60 (6322 views)
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Re: [Megatron] TELEFUNKEN PAL COLOR 2560 white horizontal lines on bright screen [In reply to] Can't Post

I'd leave G2 at a low setting, but you can still see screen is lit with retrace lines. That should minimize blinking.

There are quite a few things that could cause this.

Well since you don't have a scope to view waveforms (or an analyzer to inject video) and Telefunken doesn't seem to like stating pin or element voltages; You say the set has (I assume white noise on tuner with NO aerial) normal sound on tuner WITH aerial (and I presume normal sound with SCART input), I'd try the IC.


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Location: Far, Far Away

(This post was edited by jts1957 on Nov 28, 2014, 9:48 PM)


Megatron
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Nov 28, 2014, 11:02 PM

Post #12 of 60 (6318 views)
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Re: [jts1957] TELEFUNKEN PAL COLOR 2560 white horizontal lines on bright screen [In reply to] Can't Post

Before few years my country shut down analog TV signal so I watch TV via separate digital DVB-T tuner pluged to the scart in TV.

This blinking seems like some short cut of overloading, black screen with vertical white flash in second and screen changes the sound (not audio signal) and I see blue flashes across the rear side of screen in the dark room in that moment. It is blinking also when is DVB-T shut down, doesn't matter is there signal or not in the scart.

You think video IC 401 is causing problem?
Do you think maybe the horizontal circuit is causing the problem?
What do you think what could everithing could possible be?


jts1957
Veteran


Nov 29, 2014, 12:03 AM

Post #13 of 60 (6315 views)
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Re: [Megatron] TELEFUNKEN PAL COLOR 2560 white horizontal lines on bright screen [In reply to] Can't Post

Chicago still has a few analog low-power stations (until ?September 2015?)

With DVB-T plugged into SCART and set to a station and G2 turned as low as it will go (or producing as dim as you can get it raster) Does the screen still flash?

Blue flashes are or are NOT in the CRT NECK?

You say you have 12V at IC401 - This is the SAME 12V source (along with 205V) used in the color output transistor area - IC401 RGB outputs are the SAME DCV (.8V) - CRT cathodes are the SAME DCV (87V) Both of these will give you the White/Gray raster. (This would tend to say CRT is OK).

Since you can't put an oscilloscope on IC401 pin #8 and observe a video waveform (or not) ... I'd suggest changing IC401 and see.


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Location: Far, Far Away


Megatron
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Nov 29, 2014, 2:58 AM

Post #14 of 60 (6309 views)
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Re: [jts1957] TELEFUNKEN PAL COLOR 2560 white horizontal lines on bright screen [In reply to] Can't Post

The blue tiny many flashes on the back of the screen when the screen is tilting are only on the surface of the back screen and not in the CRT inside neck tube.

Yes, I checked colour transistor area voltage U11 and there is 205V and I checked R221 100 Ohms and and checked C80 1uF and everyting is OK but still low voltage 87V only on output for RGB cable.

I am now confused on datasheet TDA3562A stands that RGB output pins 13,15,17 has to be in range 10,7-11,3V and I measured 0,8V only, isn't that crucial fail and therefore we have 87V only instead 135-170V on RGB cable?

I'll try tomorow turn the TV with set low G2 voltage and see would the picture start to flash after some time.


Megatron
User

Nov 30, 2014, 2:21 AM

Post #15 of 60 (6287 views)
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Re: [Megatron] TELEFUNKEN PAL COLOR 2560 white horizontal lines on bright screen [In reply to] Can't Post

Found one more broken and some suspicious solders on video board. I'll desolder tomorow on the daylight all solder joints with vacuum pump on video board, CRT board, motherboard and then we will se the results. Till now I removed about 70% solder joints which looks cold or suspicious with vacuum pump but now I don't trust any of remain joints even if they look fine they will cause for few years problems. Tomorow will be 100% solder joints renew and we will see the results. Maybe there is some cold solder joint with microsparking and causing the problem and blinking. Till tomorow.


(This post was edited by Megatron on Nov 30, 2014, 2:29 AM)


Megatron
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Dec 6, 2014, 12:57 PM

Post #16 of 60 (6142 views)
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Re: [Megatron] TELEFUNKEN PAL COLOR 2560 white horizontal lines on bright screen [In reply to] Can't Post

Sorry for delay, it was a lot of work, patience and lot of time.

I have completely removed all solder joints with vacuum pump and resolder motherboard and everything pluged on motherboard such video PCB, PLL synthesizer with microcomputer for memory station PCB, then CRT PCB so everything what could cose the problem of cold solder joints is removed and there is no more blinking problem.

I bought the new video chip TDA 3562A and now when I turn down dimming the picture on G2 trimmer I can see the picture of TV station bearly in the dark and in colours which are not sharp and properly overlaping, actualy they are sharp but like blue and red shadows and there are still horizontal lines but stable and they are not moving at all. When the TV program has the bright scenes then you can see entire picture not only shadows. When you watch the film with white subtitles they are sharp and readable.

The voltage on the video chip TDA 3562A on output signal pins 13,15,17 are still the same 0,7V and on output RGB tranzistor area via RGB cable to CRT PCB still 89V instead 135-170V as it should be.
Any idea what could be failure?


(This post was edited by Megatron on Dec 6, 2014, 5:41 PM)


jts1957
Veteran


Dec 6, 2014, 8:32 PM

Post #17 of 60 (6130 views)
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Re: [Megatron] TELEFUNKEN PAL COLOR 2560 white horizontal lines on bright screen [In reply to] Can't Post

Try temporarily putting a jumper (wire) across VL831 (R203 to R204) and see if it makes any difference.


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Location: Far, Far Away


Megatron
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Dec 6, 2014, 9:23 PM

Post #18 of 60 (6128 views)
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Re: [jts1957] TELEFUNKEN PAL COLOR 2560 white horizontal lines on bright screen [In reply to] Can't Post

When I jump the VL831 the picture is slightly unsharping for about 20% but it is still visible as without jumper. (Still am watching TV via scart signal).


(This post was edited by Megatron on Dec 6, 2014, 9:29 PM)


jts1957
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Dec 6, 2014, 10:00 PM

Post #19 of 60 (6121 views)
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Re: [Megatron] TELEFUNKEN PAL COLOR 2560 white horizontal lines on bright screen [In reply to] Can't Post

Does switching it to tuner (even though you don't have analog channels) produce a snow covered screen and white hiss noise from speaker? You may have to try a number of channels.


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Location: Far, Far Away

(This post was edited by jts1957 on Dec 6, 2014, 10:01 PM)


Megatron
User

Dec 6, 2014, 10:13 PM

Post #20 of 60 (6118 views)
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Re: [jts1957] TELEFUNKEN PAL COLOR 2560 white horizontal lines on bright screen [In reply to] Can't Post

I have a snow just a little bit sparks, mostly is the picture grey and playing with the G2 trimmer I am just dimming the picture from Black-gray-to bright white screen almost white screen with horizontal lines when there is no signal.

The sound when no signal (DVB-T) turned off make normal noise when sound squelch turned off.

The bright screen is masking the snow when no signal on input there are not many pikes are going through bright screen.


(This post was edited by Megatron on Dec 6, 2014, 10:25 PM)


jts1957
Veteran


Dec 6, 2014, 11:04 PM

Post #21 of 60 (6116 views)
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Re: [Megatron] TELEFUNKEN PAL COLOR 2560 white horizontal lines on bright screen [In reply to] Can't Post

R267 & R283 = 82K? may have to disconnect one side of each to get accurate reading.

Been long time since I try troubleshooting with only DVM. No pin voltage either.

I did read correctly? You now have very weak pix with new TDA (No trace of video with the original)?
Contrast and brightness controls DO have an effect?


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Location: Far, Far Away

(This post was edited by jts1957 on Dec 6, 2014, 11:28 PM)


Megatron
User

Dec 6, 2014, 11:44 PM

Post #22 of 60 (6111 views)
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Re: [jts1957] TELEFUNKEN PAL COLOR 2560 white horizontal lines on bright screen [In reply to] Can't Post

Yes, both resistors R267 & R283 have 82k ohms.

I was testing the voltage on CRT on screen directly and on G1 I measured positive 12V, shouldn't be there on CRT pin 5 negative voltage?


jts1957
Veteran


Dec 7, 2014, 12:35 AM

Post #23 of 60 (6106 views)
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Re: [Megatron] TELEFUNKEN PAL COLOR 2560 white horizontal lines on bright screen [In reply to] Can't Post

Connector ST3083 Pin #1 = 205V Pin #5 = 12V. No negative there.


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Location: Far, Far Away


Megatron
User

Dec 7, 2014, 2:06 AM

Post #24 of 60 (6104 views)
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Re: [jts1957] TELEFUNKEN PAL COLOR 2560 white horizontal lines on bright screen [In reply to] Can't Post

Yes, it is fine on connector 3083 pin1=+205V, pin3=+6,4V, pin5=+12V


Ron.M
Veteran


Dec 7, 2014, 7:36 PM

Post #25 of 60 (6092 views)
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Re: [jts1957 & Megatron] TELEFUNKEN PAL COLOR 2560 white horizontal lines on bright screen [In reply to] Can't Post

    
jts1957;...

Please allow me to rudely butt-in briefly ..
Thanks...

Megatron;....

You appear to be on an Easter Egg hunt !!!...Shocked...
NO OFFENSE jts1957 !!!..Angelic...
The reason for the retrace lines with or without a pix is obviously due to a biasing problem at the CRT which is due to a malfunctioning Demod IC...

First , I'd suggest you remove the module from the CRT neck...
Then take re-readings of all the erroneous readings on the IC & at the CRT you got earlier & compare them with the new readings..
Please post ALL readings...
Re-install the CRT module on the CRT neck..
Then , I'd strongly suggest you take DC voltage readings at ALL the pins on IC401 & post them here...
Please do this with a signal to the TV ...
Please post ALL readings...
The new IC is not doing it's job & I suspect that a disruption of voltage/signal is at one or more of those pins..
Perhaps then jts1957 or I or ??? will then be able to get a more definitive handle as to what's going on here...


Just a suggestion...

Later...Ron.M...Cool...
Veteran & Retired TV technician

(This post was edited by Ron.M on Dec 7, 2014, 7:45 PM)

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