If it were mine, I would try it. If the grid leak is defective, you will either hear it as noise, or no radio signal at all. Tuning might be very tricky. Short of the specific value for the grid leak, short of opening the radio up to check the grid leak, and what is imprinted on it. It might also be a situation where the solder joints on the grid leak connection are breaking down- Which can result in a high resistance joint.
:I have been going through a pristine Radiola 25 per the RCA service notes, prior to hooking up a battery eliminator. All readings appear normal except one. A continuity test between G4 and terminal 12 should read "open through grid leak"(with a 4.5V battery and a 4.5v meter for full deflection or headphones).I am using a digital multi-meter and see 9.68M Ohms resistance. The schematic does not show the values of any of the capacitors or resistors. The defect for incorrect reading is an open grid leak or coil #8. I am not sure if 9.68 Meg Ohms (decreases over a short time from 11Meg Ohms, is a good indication for the grid leak resistor. I would rather not open up the factory sealed gang socket assembly in the catacomb unless it is truly necessary. Can anyone give me some pointers or values to be expected in this old radio.
:Thanks
:Jeff
:Hi,
:Normal Grid leaks that I have encountered usually ranged from 250k at the low end to 5M at the high end, and like regular resistors of the era, they can shift in value. It really should not hurt anything to power it up as it is just to see if it works well enough for reception. High grid leak values increase selectivity, but can also give a distorted output.
:
:If it were mine, I would try it. If the grid leak is defective, you will either hear it as noise, or no radio signal at all. Tuning might be very tricky. Short of the specific value for the grid leak, short of opening the radio up to check the grid leak, and what is imprinted on it. It might also be a situation where the solder joints on the grid leak connection are breaking down- Which can result in a high resistance joint.
:
:
::I have been going through a pristine Radiola 25 per the RCA service notes, prior to hooking up a battery eliminator. All readings appear normal except one. A continuity test between G4 and terminal 12 should read "open through grid leak"(with a 4.5V battery and a 4.5v meter for full deflection or headphones).I am using a digital multi-meter and see 9.68M Ohms resistance. The schematic does not show the values of any of the capacitors or resistors. The defect for incorrect reading is an open grid leak or coil #8. I am not sure if 9.68 Meg Ohms (decreases over a short time from 11Meg Ohms, is a good indication for the grid leak resistor. I would rather not open up the factory sealed gang socket assembly in the catacomb unless it is truly necessary. Can anyone give me some pointers or values to be expected in this old radio.
::Thanks
::Jeff