10-05-2021, 08:38 PM
Hi Tonto. The thread has very good suggestions. I am a big believer in "Divide and conquer" troubleshooting.
Before anything else:
Caution! This radio is a "Hot Chassis (even if isolated by a capacitor) with a very real shock hazard. Worse yet, the power switch switches the neutral instead of the hot connection. Either use an isolation transformer or use a meter to ensure that the chassis is at neutral (ground potential by checking voltage between the chassis and ground. If voltage reading is near 120V then reverse the orientation of the power plug. Check agin for a low voltage between chassis and ground. Do not turn the switch off or then the chassis becomes hot again due to the continuity of the tube filaments.
If U wanna get down and dirty, look at the schematic from Ryders and break the connection between the volume control and the detector stage. connect a source such as an MP3 Player. If the sound is good, this eliminates the power supply, volume control and amplifier section. If this is not the way you wanna go then:
First test- Turn down the volume control and smack the radio around (Tap individual components with non metallic object). Static? Then check volume control, Power Supply(Including filter and all 'bypass' caps and Audio Section If good, then:
Second test- Set the Tuning Cap (Capacitor) to full open (1700KHz). Vary volume control. Static? If good, leave volume control high. Smack radio around Static? If so, then check connections, tap individual tubes, components, etc. If no static, then:
Third test- Slowly tune down till the first station is heard. Static, if not, then continue tuning downward. If static starts as the tuning cap plates start to mesh, tune up again and then tune back down. If the static starts at the same place on the dial scale the the tuning cap has dirt or aluminum oxide between plates or the plates touch.
One method is to take a feeler gauge and run between the rotor and stator plates. then blast with canned air or leaf blower. Also check the piece of spring copper that connects the rotor to the cap frame.
If static occurs only when the radio is played loud, then the voice coil wires (the flexible ones that go from the cone to the frame) may be intermittent.
Static can also occur from internal arcing from any of the coupling or bypass capacitors. The IF transformers may have issues (Silver Mica Disease), but that is the last place to go.
Hope this helps.
Best Regards,
Mr Fixr
Before anything else:
Caution! This radio is a "Hot Chassis (even if isolated by a capacitor) with a very real shock hazard. Worse yet, the power switch switches the neutral instead of the hot connection. Either use an isolation transformer or use a meter to ensure that the chassis is at neutral (ground potential by checking voltage between the chassis and ground. If voltage reading is near 120V then reverse the orientation of the power plug. Check agin for a low voltage between chassis and ground. Do not turn the switch off or then the chassis becomes hot again due to the continuity of the tube filaments.
If U wanna get down and dirty, look at the schematic from Ryders and break the connection between the volume control and the detector stage. connect a source such as an MP3 Player. If the sound is good, this eliminates the power supply, volume control and amplifier section. If this is not the way you wanna go then:
First test- Turn down the volume control and smack the radio around (Tap individual components with non metallic object). Static? Then check volume control, Power Supply(Including filter and all 'bypass' caps and Audio Section If good, then:
Second test- Set the Tuning Cap (Capacitor) to full open (1700KHz). Vary volume control. Static? If good, leave volume control high. Smack radio around Static? If so, then check connections, tap individual tubes, components, etc. If no static, then:
Third test- Slowly tune down till the first station is heard. Static, if not, then continue tuning downward. If static starts as the tuning cap plates start to mesh, tune up again and then tune back down. If the static starts at the same place on the dial scale the the tuning cap has dirt or aluminum oxide between plates or the plates touch.
One method is to take a feeler gauge and run between the rotor and stator plates. then blast with canned air or leaf blower. Also check the piece of spring copper that connects the rotor to the cap frame.
If static occurs only when the radio is played loud, then the voice coil wires (the flexible ones that go from the cone to the frame) may be intermittent.
Static can also occur from internal arcing from any of the coupling or bypass capacitors. The IF transformers may have issues (Silver Mica Disease), but that is the last place to go.
Hope this helps.
Best Regards,
Mr Fixr
"Do Justly, love Mercy and walk humbly with your God"- Micah 6:8
Best Regards,
MrFixr55
