I’m Back! Pilot TV37

[Phil Nelson]

Leave tubes in their sockets. Note #3 under the charts says the resistance is measured “from the common negative unless otherwise indicated.” The little footnotes under the resistance chart specify alternate connection points for a few measurements.

Phil Nelson

[Chris K]

Originally Posted by Phil Nelson

Leave tubes in their sockets. Note #3 under the charts says the resistance is measured “from the common negative unless otherwise indicated.” The little footnotes under the resistance chart specify alternate connection points for a few measurements.

Phil Nelson

Filling in an Excel spreadsheet with the listed values and actual values. I'm doing it by tube number that starts in the front end with the 3 12AT7s and I've already found wacky values. I'll post it when I'm done. Maybe someone with good investigative skills can tell me what I'm missing

[Phil Nelson]

Also note jr_tech’s comment about checking the heater connections throughout the tube strings. On page 2 of the Sams schematic, the diagrams at the far lower left show all those heater connections.

You can see that pin 7 of V20 connects to pin 8 of V21, and so on down the line. Using your ohmmeter, you can check these connections for continuity, working from one tube to the next.

Phil Nelson

[Chris K]

Originally Posted by Phil Nelson

Also note jr_tech’s comment about checking the heater connections throughout the tube strings. On page 2 of the Sams schematic, the diagrams at the far lower left show all those heater connections.

You can see that pin 7 of V20 connects to pin 8 of V21, and so on down the line. Using your ohmmeter, you can check these connections for continuity, working from one tube to the next.

Phil Nelson

Got it Phil...working through it

[Chris K]

Originally Posted by Phil Nelson

Also note jr_tech’s comment about checking the heater connections throughout the tube strings. On page 2 of the Sams schematic, the diagrams at the far lower left show all those heater connections.

You can see that pin 7 of V20 connects to pin 8 of V21, and so on down the line. Using your ohmmeter, you can check these connections for continuity, working from one tube to the next.

Phil Nelson

OK I measured all of the resistance values as instructed in the Sams. I checked filament continuity in the strings and they are all fine with no breaks. I thought I would start describing the situation with the 35W4 negative rectifier as that's one of the first power tubes to come off the ballast. All of the pin resistances are fine except for pin 5 that's supposed to be 33k and it's unreadable jumping all over the place from 0 ohms to 4 meg when I put the probe to it. Pin 5 of it goes to pin 8 of the HV oscillator 25L6 but all of the pin resistances on the HV Osc. are close to the table values. Then on the HV rectifier 1B3, there are many pins off value. Pin 4 is bouncing all over like pin 5 of the 35W4 and pins 2 and 3 that are supposed to give infinite values are reading low ohms; 21 for pin 2 and 0.3 for pin 3. Arughhhhhh! Does that give you any enlightenment? I did replace all of the electrolytics. The TV worked after I replaced them...sorta but these most recent issues appeared after replacing about 15 resistors.