06-10-2020, 08:46 PM
Hello everybody
I am a new real fan of the forum and I just started this new adventure with the Vintage tube Radios. I found a 42-327 radio and thanks to the multiple suggestions on this forum I started from the Electrolytic Capacitor. I didn't find 2oUF and I used the 33uF 450V.
The cabling was very bad a lot of "burnt" plastic wire and I changed most of them together with all the old capacitors ( except the 0.2Uf with the coil) and 4 bad resistances.
I am focusing now on the XXD Tube and broadcast band and when I checked the voltage on the tube I have between the chassis and pin 3 40 VDC ( after 10 second become 35) and on pin 6 55 VDC. But what happened was also that touching only the pin 4 with the tester cable the broadcast reception work with not a clear reception but with multiple stations. As soon as I disconnect the cable the radio come back to a white noise.
I checked the mica capacitor on pin 4 and was ok ( there is already installed a 100pF not a 50pF as in the schematic ) . I tried it with a dmm and it is 100pF and I tried in any case to change with a new one,but the only result was that touching with the "famous" tester cable the reception became bad. I put in place again the old one and the situation is stable as the beginning. THe receptions is ok only when I touch with a cable the pin 4 of the XXD. I checked and changed the bad resistor 12 and 11 and verified the resistor 25.
I also checked the voltage between pin 7 and pin 8 and it is 3.4 VDC. but between pin 1 and pin 2 only millivolts. Is it normal? What other measure can I do on the tube? Resistance and voltage?
I checked all the contacts on the Tube pins with cleaner and sands paper and on the socket and on soldered pin. I ordered a new 14AF NOS tube because I didn't find an XXD one. I will receive it the end of next week.
Last but not least unfortunately my tools are only a DMM and a soldier what I can try more?
Thanks
I am a new real fan of the forum and I just started this new adventure with the Vintage tube Radios. I found a 42-327 radio and thanks to the multiple suggestions on this forum I started from the Electrolytic Capacitor. I didn't find 2oUF and I used the 33uF 450V.
The cabling was very bad a lot of "burnt" plastic wire and I changed most of them together with all the old capacitors ( except the 0.2Uf with the coil) and 4 bad resistances.
I am focusing now on the XXD Tube and broadcast band and when I checked the voltage on the tube I have between the chassis and pin 3 40 VDC ( after 10 second become 35) and on pin 6 55 VDC. But what happened was also that touching only the pin 4 with the tester cable the broadcast reception work with not a clear reception but with multiple stations. As soon as I disconnect the cable the radio come back to a white noise.
I checked the mica capacitor on pin 4 and was ok ( there is already installed a 100pF not a 50pF as in the schematic ) . I tried it with a dmm and it is 100pF and I tried in any case to change with a new one,but the only result was that touching with the "famous" tester cable the reception became bad. I put in place again the old one and the situation is stable as the beginning. THe receptions is ok only when I touch with a cable the pin 4 of the XXD. I checked and changed the bad resistor 12 and 11 and verified the resistor 25.
I also checked the voltage between pin 7 and pin 8 and it is 3.4 VDC. but between pin 1 and pin 2 only millivolts. Is it normal? What other measure can I do on the tube? Resistance and voltage?
I checked all the contacts on the Tube pins with cleaner and sands paper and on the socket and on soldered pin. I ordered a new 14AF NOS tube because I didn't find an XXD one. I will receive it the end of next week.
Last but not least unfortunately my tools are only a DMM and a soldier what I can try more?
Thanks
