04-21-2016, 06:02 AM
> What should I look for on the shadow meter?
Well there is bunch of stuff. The meter it self the vane could be stuck or broken or the permanent magnet may need to be remagnetized. The good thing here is that we know that the coil is good.
On the chassis I'd check the voltages at the tube against the diagram. They will probably read a little high because of your modern meter. This is ok as long everything you measure comes up a little higher maybe 10-15 percent. Voltages at the plate or screen grid that are too low, control grid voltages are too negative, or cathode voltages that high will affect the gain of the tubes. The ones to check are the mixer, IF amps, and detector. This in turn will affect the current flow though the meter. Check resistors that are 1meg or higher. These are mostly found in the radio's avc (automatic volume control) circuit. They affect the gain. Weak tubes in these positions can be a problem too. RF and IF alignment will affect also.
http://www.philcorepairbench.com/tips/svctip01.htm
Terry
If life gives you melons you may be lisdexic
Well there is bunch of stuff. The meter it self the vane could be stuck or broken or the permanent magnet may need to be remagnetized. The good thing here is that we know that the coil is good.
On the chassis I'd check the voltages at the tube against the diagram. They will probably read a little high because of your modern meter. This is ok as long everything you measure comes up a little higher maybe 10-15 percent. Voltages at the plate or screen grid that are too low, control grid voltages are too negative, or cathode voltages that high will affect the gain of the tubes. The ones to check are the mixer, IF amps, and detector. This in turn will affect the current flow though the meter. Check resistors that are 1meg or higher. These are mostly found in the radio's avc (automatic volume control) circuit. They affect the gain. Weak tubes in these positions can be a problem too. RF and IF alignment will affect also.
http://www.philcorepairbench.com/tips/svctip01.htm
Terry
If life gives you melons you may be lisdexic
