12-05-2019, 01:49 PM
I'm ready to start restuffing condenser blocks. I have a new set of "dogbone" resistors that I will be installing at the same time.
[Image: https://live.staticflickr.com/65535/4916...ebf6_k.jpg]Philco 90 Restoration by Steve Davis, on Flickr
When I look at the bottom of the chassis, I can see a few problems. The most noticeable is the end section of the B-C resistor is burned. This section provides the bias for the 47 tubes. It reads 195 ohms, it should be 205. That makes me wonder if there one or two turns shorted. I may cut that section out and replace it with a separate resistor.
[Image: https://live.staticflickr.com/65535/4916...7dbf_k.jpg]Philco 90 Restoration by Steve Davis, on Flickr
Another thing is, someone in the past, added an extra capacitor that makes no sense. Originally there was a .25 uf located in a metal can with 3 other sections that by passes a 25K resistor going to the 27 detector amp. This lead to the .25 uf was clipped and the .01 cap was connected in series with the .25 uf. This looks to have been done many years ago.
[Image: https://live.staticflickr.com/65535/4917...9531_k.jpg]Philco 90 Restoration by Steve Davis, on Flickr
Steve
[Image: https://live.staticflickr.com/65535/4916...ebf6_k.jpg]Philco 90 Restoration by Steve Davis, on Flickr
When I look at the bottom of the chassis, I can see a few problems. The most noticeable is the end section of the B-C resistor is burned. This section provides the bias for the 47 tubes. It reads 195 ohms, it should be 205. That makes me wonder if there one or two turns shorted. I may cut that section out and replace it with a separate resistor.
[Image: https://live.staticflickr.com/65535/4916...7dbf_k.jpg]Philco 90 Restoration by Steve Davis, on Flickr
Another thing is, someone in the past, added an extra capacitor that makes no sense. Originally there was a .25 uf located in a metal can with 3 other sections that by passes a 25K resistor going to the 27 detector amp. This lead to the .25 uf was clipped and the .01 cap was connected in series with the .25 uf. This looks to have been done many years ago.
[Image: https://live.staticflickr.com/65535/4917...9531_k.jpg]Philco 90 Restoration by Steve Davis, on Flickr
Steve
M R Radios C M Tubes
