03-16-2014, 10:29 AM
I agree with Ron 100% that making sure the circuit is wired right and the components are correct per the schematic is the very first thing to check when encountering a problem. And I had ordered a 700 pF but when it came time to install it, it was MIA. Couldn't find it anywhere, even after ransacking the workbench and muttering a few choice adjectives. That was my mistake, or carelessness, whichever you prefer. So I looked what I had on hand that might work, and the .0015 mfd was as close as I could find. It was only after I grabbed the manual for my RF signal generator and began paging through it did this little black thing come rolling out. How it got there, I'll never know, but that was the 700 pF I was pulling my hair out trying to find! So I immediately took out the .0015 and installed it.
When I wrote "I doubt it would've made much difference", I was referring to the SW problem. I had my doubts that that one change in value would cause me to receive the wrong band. And indeed after I installed the correct 700 pF it didn't change anything. The fact that Gregb's set is playing with the 36 tube and a .0015 mfd cap confirms my assumption. Does that mean it's right to use a wrong value cap? Of course not. But sometimes, in one's eagerness, you try using what you have on hand that's close. We've all done it at some point, I'm sure. If you would've seen this chassis when I began on it, your jaw would've dropped as mine did. There were so many components soldered in that didn't belong there (my favorite were two bullet sized wire wound resistors soldered in parallel with a wax cap soldered to them for good measure) that I had to trace out every single wire and connection on this chassis based on the schematic. And I've never had a set where I had to go to that extreme on before.
Speaking of schematics, I have to offer my deepest gratitude to Ron for assembling that Model 89 evolution page on this site. Invaluable doesn't even begin to describe how helpful that was in the detective work figuring out just where my set fell into the run. The first and most obvious clue was the #36 tube, but then seeing K-21 stamped on my speaker further narrowed it down to within 3 schematics. There were a few other clues but those were the main one's.
I had started with an 8.2K 36 cathode resistor, but when I wasn't even on the right band, taking a tip from Ron's "ANOTHER PHILCO 89 FROM H**l" document on Chuck's site, I went down to a 7.5K. It didn't change anything, as my problem all boiled down to a miswound OSC coil.
I have the greatest respect for Ron for the vast knowledge he possesses and for all he's done to aid folks restoring Philco radios for so many years. You learn a lot and gain lots of experience in 40 years, I'm sure. I'll be 42 in July, and I've only been restoring radios since high school. But most of my experience was with post war sets. This was my first experience with re-stuffing bakelite blocks AND rewinding coils. I made a lot of mistakes, and I'll be the first to admit it and to admit that I still have a LOT to learn. But I consider it a major accomplishment, despite all of the obstacles I encountered along the way, that this set plays at all. And I couldn't have imagined making that happen without this site, Ron's wonderful resources, and the generous and kind people here willing to help a newcomer along
When I wrote "I doubt it would've made much difference", I was referring to the SW problem. I had my doubts that that one change in value would cause me to receive the wrong band. And indeed after I installed the correct 700 pF it didn't change anything. The fact that Gregb's set is playing with the 36 tube and a .0015 mfd cap confirms my assumption. Does that mean it's right to use a wrong value cap? Of course not. But sometimes, in one's eagerness, you try using what you have on hand that's close. We've all done it at some point, I'm sure. If you would've seen this chassis when I began on it, your jaw would've dropped as mine did. There were so many components soldered in that didn't belong there (my favorite were two bullet sized wire wound resistors soldered in parallel with a wax cap soldered to them for good measure) that I had to trace out every single wire and connection on this chassis based on the schematic. And I've never had a set where I had to go to that extreme on before.
Speaking of schematics, I have to offer my deepest gratitude to Ron for assembling that Model 89 evolution page on this site. Invaluable doesn't even begin to describe how helpful that was in the detective work figuring out just where my set fell into the run. The first and most obvious clue was the #36 tube, but then seeing K-21 stamped on my speaker further narrowed it down to within 3 schematics. There were a few other clues but those were the main one's.
I had started with an 8.2K 36 cathode resistor, but when I wasn't even on the right band, taking a tip from Ron's "ANOTHER PHILCO 89 FROM H**l" document on Chuck's site, I went down to a 7.5K. It didn't change anything, as my problem all boiled down to a miswound OSC coil.
I have the greatest respect for Ron for the vast knowledge he possesses and for all he's done to aid folks restoring Philco radios for so many years. You learn a lot and gain lots of experience in 40 years, I'm sure. I'll be 42 in July, and I've only been restoring radios since high school. But most of my experience was with post war sets. This was my first experience with re-stuffing bakelite blocks AND rewinding coils. I made a lot of mistakes, and I'll be the first to admit it and to admit that I still have a LOT to learn. But I consider it a major accomplishment, despite all of the obstacles I encountered along the way, that this set plays at all. And I couldn't have imagined making that happen without this site, Ron's wonderful resources, and the generous and kind people here willing to help a newcomer along
Greg V.
West Bend, WI
Member WARCI.org
