Re: Grundig CUC 2401 CRT TV - Brightness is too high
Yes they are digitally set.
On the tv there are two eeprom, one is SDA2216 inside the tuner unit (page 11 of schematic) and the other is on the teletext board (page 17, there are two SDA2216 on the schematic but my teletext board only has one SDA2526).
Could any of these store the brightness value ?
Or could be stored inside IC811 and sent to TDA8442 at start ?
Thank you...
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Re: Grundig CUC 2401 CRT TV - Brightness is too high
Hello, the screen voltage is correct I don't think it is related to that because lowering the brightness manually from the menu option fixes the problem and pin 16 of TDA8442 goes in the right range of about 2V.
But every time I switch on the tv it comes back to 3.2V and I have to lower brightness again.
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Grundig CUC 2401 CRT TV - Brightness is too high
Hello, I'm trying to fix a Grundig CUC 2401 with picture brightness too high.
The problem seems to be in the brightness voltage supplied by pin 16 of TDA8442 that should be in the 1-3V range instead it is about 3.2V.
If I manually lower the brightness the voltage goes in the right range of about 2V and doesn't increase but I don't understand why at start up it is set wrong ?
I've already changed TDA8442, the video output IC TDA3505 and the microcontroller IC811 but it didn't fix.
The collector of RGB transistors on crt board are about 170V for red and blue but 150V...
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Re: CRT TV - Blue spark inside glass neck related to focus
Hello, it isn't easy to take a picture because they are fast.
They are like little flashes of light appearing and disappearing when focus pot is at max and the blue spark inside the crt glass is brighter.
Is there a way to check if the tube is ok ?...
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CRT TV - Blue spark inside glass neck related to focus
Hello, when I power on the TV there is a blue little spark inside the crt glass neck that increases and decreases in intensity with the focus, when focus pot is at minimum it is invisible when it is at max it is brighter and makes some dots on the screen appearing and disappearing randomly.
The picture is fine and the TV has no problems.
I've cleaned the crt plastic socket, pins and the spark gap contacts so I don't understand what could cause it
Could some more experienced member help me to troubleshoot it ?
Some picture attached for better...Last edited by Flybacks; 12-01-2021, 02:41 PM.
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Crt TV Repair - Microcontroller issue ?
Hello all!
I have an old Crt TV but mistakenly I touched some pins of the micro controller that handles the remote and the keyboard buttons.
The TV shut down then I switched on again but now the remote controller has no effect and the only buttons that work are for changing channel but cannot set volume ,brightness etc anymore.
Before I touched the pins all worked perfectly.
May the micro controller got somehow corrupted ?
And if so changing it with same model may solve the problem or these things are programmed by the tv manufacturer so the...
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