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Equipment Repairs => CRT TV forum => Topic started by: opr on July 31, 2009,08:27:23

Title: Grundig chasis TV4K, model STF 72-1002/7 text
Post by: opr on July 31, 2009,08:27:23

Single horizontal blue line.
I have changed STV9306B, all condensators, cheked all resistors and semiconductors in vertical output. Pin5 on IC(sync) is 0V and pin7(flyback) is 0V. Output VOUT on pin9 is 22,5V linear (there is no saw). Supply is OK(24,5V).
Any suggestion what to do next? Vertical synchronisation STV9306B get from STV2248 pin47.
Is it posibile that TV set has service horizontal line?
Thank you for your help.

Title: Re: Grundig chasis TV4K, model STF 72-1002/7 text
Post by: sparky on July 31, 2009,11:00:58

hi
have you checked the scan coils and socket for dry joint
also check the supply coming from loptx
sparky

Title: Re: Grundig chasis TV4K, model STF 72-1002/7 text
Post by: opr on July 31, 2009,14:19:28

Thank you :thumbup:
Yes, I cheked coil and "breathing" voltage from line transformator. Pin15 on STV9306B is 5V.
That TV set get lightning from mains supply(230V, 50Hz). First changed many parts in power supply and get good voltages.
I dont know what to do next with that line.I repaired vertical output on TV sets many times.:wallbash:

Title: Re: Grundig chasis TV4K, model STF 72-1002/7 text
Post by: opr on August 12, 2009,02:21:21

Fixed. :clap:

It was IC STV2248H.  :dubbio:

Title: Re: Grundig chasis TV4K, model STF 72-1002/7 text
Post by: veromade on August 19, 2009,22:17:53

I solved my problem
really thanks