06-28-2021, 05:25 PM
I still have a couple of things to chase down, before it is really satisfactory.
After tackling the bad section of the Candohm with a temporary patch, I retested with full connection to AC. The set would work well for a while, but eventually go quiet, still receiving, but very low volume and sensitivity. Now the HT was high (335V rather than 305 V in the service notes), thanks to modern line voltage . The poor 6F6 was also getting far too hot under these conditions. If the set is turned off for a minute, it recovers and operates for a while before going quiet again. Returning to the dim-bulb tester, the radio is stable, but with only 180V HT it is weak as would be expected.
Next step will be to check resistors and voltages more thoroughly, and see if something funny is happening with bias and AGC lines. I may also have a transformer that can be used to "buck" the AC down towards the 115 V the radio expects. Our line was around 118 - 119 yesterday, according to my DMM, but I have seen it range higher.
After tackling the bad section of the Candohm with a temporary patch, I retested with full connection to AC. The set would work well for a while, but eventually go quiet, still receiving, but very low volume and sensitivity. Now the HT was high (335V rather than 305 V in the service notes), thanks to modern line voltage . The poor 6F6 was also getting far too hot under these conditions. If the set is turned off for a minute, it recovers and operates for a while before going quiet again. Returning to the dim-bulb tester, the radio is stable, but with only 180V HT it is weak as would be expected.
Next step will be to check resistors and voltages more thoroughly, and see if something funny is happening with bias and AGC lines. I may also have a transformer that can be used to "buck" the AC down towards the 115 V the radio expects. Our line was around 118 - 119 yesterday, according to my DMM, but I have seen it range higher.
I don't hold with furniture that talks.
