I have the datasheet of the rectifier and I the schematic says that in the output of the rectifier there are 130 ma. The friend who gave me the radio is also going to give me a 220-125 V transformer. Is this going to work?
It looks as if the mains transformer HT winding has failed, and someone has put mains directly onto the GZ32. This would only give halfwave rectification, so would hum a bit.
Your best be would to fit a new transformer eg the 100w one mentioned here.
You could then use 2 1N4007's as mentioned .
Or you could use direct mains and 4 1N4007's in a bridge. This gives a live chassis - not nice, but almost all valve tv's were like this.
I suggested an inrush limiting NTC thermistor in series ( see my link.) One rated with a 'hot' resistance of 1-200 ohms at 150mA would be about right. Rating >2 watts.
It's almost certain that in such an old set the electrolytic caps will have failed, as will the interstage coupling paper ones. I'd replace the lot as a matter of course.
Allan
Thanks for all the help!
I will proceed with the repairs!
allanhurst:
It's almost certain that in such an old set the electrolytic caps will have failed, as will the interstage coupling paper ones. I'd replace the lot as a matter of course.Allan
Yes, that's good advice - old electrolytics at the very least would need careful reconditioning whilst
monitoring leakage currents, and they are probably dried out anyway. Try to find higher temperature
rated electrolytics if possible for a long life near all those heaters (well designed valve equipment keeps
all the passive components underneath away from the heat).