Thunderclap
New Member
I need diode CR1 in the parts list is is designated as Diode type 1112.Does any one know what the sub for it is?
Thunderclap;
True, there is a path, but the resistance is pretty high at 150K ohms for R47, and R45, a 100K ohm is connected to R47 making a voltage divider. The apparent intent is to produce a bias voltage at that point. Now that I look at the schematic closer, I am wondering if there is a mistake on the schematic. The +170VDC feed gets to the junction of R47 and R45 through R49, a 22 Meg ohm resistor??? I don't think so. I would need to check the actual wiring, but passing B+ for an IF stage through a 22 Meg ohm resistor makes no sense. It makes me wonder if the R49 value has been swapped with the value of R47 or possibly some other value of resistance for R49, but not 22 Meg ohms. It would not be normal for B+ to be present on the detector secondary winding of an AM detector circuit. There is a somewhat similar detector arrangement used in the 800C, but I do not see the same thing used in the Electra IV or V AM circuitry. That said, a 1N914 can stand a repetitive reverse voltage of 75V and a non-repetitive voltage of 100V.
I will be out of pocket for the next few days. Once I get a chance I want to investigate the actual wiring in my 490-T to see if the wiring is actually as the schematic says. Passing B+ to an IF gain stage through a 22 Meg ohm resistor just does not make any reasonable sense to me.
Joe