Hello, I found a schematic here but I would like the service manual that would have the parts list and locations as well as alignment instructions. Can someone help me out with that? I found another one on Tom Bavis's site but the alignment instructions are not there.
I just recently picked this radio up and it appears to have all original tubes (globes with Philco paper label) and they test very good. The cabinet needs a lot of veneer work. Looks like it got wet. The speaker is frozen. I will do a separate post for that.
It will a while before I get to this radio. Looking forward to it though.
Hello, I have begun the restoration of my Philco 91. I have been looking over the parts and the very first one I checked is way off. It is a 160K resistor connected to pin 4 of the 44 (RF) tube. It looks factory. That resistor does not exist on any of the schematics I have for that radio. The schematic shows connection from pin 4 of the RF tube to pin 4 of the IF tube with nothing in between. The other end of the resistor connects to block 9. Also the connection between pin 4 of the RF and IF is through a switch. This switch is on the same post as the on/off switch. It will be the bottom switch in the picture.
I found a schematic on Nostalgia Air showing the switch as being a frequency switch. There is only one band on the radio. The NA schematic is for code 126-226. The schematic is here http://www.nostalgiaair.org/pagesbymodel...013884.pdf. Off to a crazy start already.
I can't explain this specific resistor but I have seen the use of a switch to apply B+ voltage to screen grids of rf tubes to give a boost in gain to pull in distant stations. The switch was called a range or local/distance switch. Does the resistor connect to the ground terminal of block 9? It may be there to reference the grids to ground when the B+ is switched off. That would make the tubes run as triodes.