This radio is just dead. No station sound. If I disconnect the cap lead to the 6A8 and put a long wire there instead, then I can hear stations but not real clear, not bad though. What could be wrong??

Looking at the plate of the 6A8 with a scope I can see rf but fades away to nothing if I tune the tuning knob back and forth either way very far.

Could be a dirty or damaged gang condenser. Try cleaning between the blades with a thin business card to dislodge anything conductive that might be in there.

With the condenser disconnected from the circuit, check for shorts by connecting a meter to the stator and rotator plates and moving the part through its range of motion. If you detect a short in this manner, you may be able to verify its location by sliding the business card (or other suitable insulator) in there to see if the RF then returns. Just make sure not to spread the blades too far and create a different short.

If the blades are OK, it is also possible that in certain positions, the bearings of the tuning condenser are interfering with the grounding of the movable blades. Not sure how you would fix this but its another possibility.

Randy

:This radio is just dead. No station sound. If I disconnect the cap lead to the 6A8 and put a long wire there instead, then I can hear stations but not real clear, not bad though. What could be wrong??
:
:Looking at the plate of the 6A8 with a scope I can see rf but fades away to nothing if I tune the tuning knob back and forth either way very far.

It is a very good idea when a tuning condenser is dirty, to clean the condenser well and then re-lubricate it. Use very hot water and detergent. First put dish detergent all over the condenser and allow it to soak in. Then take a tooth brush and gently scrub everywhere including between the plates. Then rinse in hot water very well. Then dip in a bath of mineral spirits to remove other oils and dirt missed by the soap. Use a tooth brush here as well. Then wash again with soap and water. Dry in the oven at 200 degrees. Allow the oven to come up to temperature once. Then, when the flame (or electric coil) goes out, turn off the oven. This is just the right amount of heat for drying the condenser. Some condensers do not require the mineral spirits treatment. If the condenser comes clean with just soap and water, omit the mineral spirits. Once the condenser is thoroughly dry, check with a meter for shorts. Grease the ball bearing with di-electric or servo grease. Also grease the bearing at the other end and the contact springs, if any. You may rub the frame down with a thin layer of motor oil by hand if you wish--use a thin film on your fingers only; no more. This will retard tarnishing of the nickel finish to some degree. Do not get oil on the plates or insulators or trimmers.

I have found that sometimes the yellow dirt and grime can cause trouble even when there are no obvious shorts. Because of this, it is important to have a clean condenser. Once the condenser is clean, you will enjoy its looks anyway, and you will want to make the entire chassis look just as fine.

Of course if you didn't think of this already, be sure to dispose of mineral spirits and rags soaked with mineral spirits appropriately (out-of-doors). Do not get any of the above near your oven or furnace or water heater.

Thomas

Thanks--that worked. I took the condenser out of the radio--somewhat of a job--and then cleaned it real good and dried with a hair dryer. While out I noticed that some of the plates were bent and touching each other so straightened them and reinstalled. The radio now works. Only gets a few stations but much better. What kind of oil can I use? I don't have di-electric or servo oil. Where can I get that kind of oil?

Thanks again,
John

:It is a very good idea when a tuning condenser is dirty, to clean the condenser well and then re-lubricate it. Use very hot water and detergent. First put dish detergent all over the condenser and allow it to soak in. Then take a tooth brush and gently scrub everywhere including between the plates. Then rinse in hot water very well. Then dip in a bath of mineral spirits to remove other oils and dirt missed by the soap. Use a tooth brush here as well. Then wash again with soap and water. Dry in the oven at 200 degrees. Allow the oven to come up to temperature once. Then, when the flame (or electric coil) goes out, turn off the oven. This is just the right amount of heat for drying the condenser. Some condensers do not require the mineral spirits treatment. If the condenser comes clean with just soap and water, omit the mineral spirits. Once the condenser is thoroughly dry, check with a meter for shorts. Grease the ball bearing with di-electric or servo grease. Also grease the bearing at the other end and the contact springs, if any. You may rub the frame down with a thin layer of motor oil by hand if you wish--use a thin film on your fingers only; no more. This will retard tarnishing of the nickel finish to some degree. Do not get oil on the plates or insulators or trimmers.
:
:I have found that sometimes the yellow dirt and grime can cause trouble even when there are no obvious shorts. Because of this, it is important to have a clean condenser. Once the condenser is clean, you will enjoy its looks anyway, and you will want to make the entire chassis look just as fine.
:
:Of course if you didn't think of this already, be sure to dispose of mineral spirits and rags soaked with mineral spirits appropriately (out-of-doors). Do not get any of the above near your oven or furnace or water heater.
:
:Thomas

You may use a dab of axle grease. Di-electric grease and axle grease are both available from your local automotive parts store. You may also try a hardware store. Work the grease into the ball bearings. The other end of the condenser may have ball bearings or it may not. If the shaft simply butts against the end of the frame, grease mentioned above may be worked in here with a toothpick, or a drop of regular motor oil (10W 30 or similar) will work fine (3-in-1 is also good). Use a drop of the above mentioned oil at the brass (possibly other metal) spring contacts that contact the shaft in-between each condenser gang. Do not get oil or grease on the condenser plates.

Thomas