I have just acquired this Grundig CTV, but has loss of both Vertical and Horizontal Synchronisation, also picture showing negative. Tried to change TDA2595 OSC. IC but no change. I have no circuit diagram for the same.

Kindly advise possible causes of loss of sync and negative picture.

Regards

Rabson Mhango

Hello Rabson, I don't have any details of your set but the loss of synchronization is likely due to the negative picture. If it's caused by a fault in the receiver section, the synch. pulses will be reversed (negative) also and probably clipped too, loosing synchronization. It could be overload, perhaps due to an AGC fault. Try pulling out the aerial plug and just hold it near the socket so only a weak signal is fed into the set. If it's running at full gain it should give a snowy picture without overload with the small signal, in which case you'll have to find the fault in that part of the set. It could be a bad IF IC, SAW filter, electrolytic in the AGC circuit, etc. Measure the voltages on the ICs and AGC line. If you don't have a schematic, do a search on the web for data for the ICs, that should give typical connections and voltages.
Don Black.

: I have just acquired this Grundig CTV, but has loss of both Vertical and Horizontal Synchronisation, also picture showing negative. Tried to change TDA2595 OSC. IC but no change. I have no circuit diagram for the same.

: Kindly advise possible causes of loss of sync and negative picture.

: Regards

: Rabson Mhango

: I have just acquired this Grundig CTV, but has loss of both Vertical and Horizontal Synchronisation, also picture showing negative. Tried to change TDA2595 OSC. IC but no change. I have no circuit diagram for the same.

: Kindly advise possible causes of loss of sync and negative picture.

: Regards

: Rabson Mhango

I have only the data sheet of the TDA2595. It is on my homepage under http://de.geocities.com/electronicfox2001/datasheet/TDA2595.pdf. Still different data sheets under www.electronicfox.at.tf.