08-31-2022, 06:09 PM
John and Terry - Thank you! I pulled the 41 and R33 and R34 did not get hot. Put 41 back in and and R33 got hot again. Replaced C27 and R33 no longer gets too hot and voltages are getting closer to where they should be - voltage between chassis ground and common negative of C31 is now 14.85 VDC. Biggest issue now is that 41 tube plate voltage reads 292VDC when it should be 200. There is non-tunable hum from the speaker now (nothing before).
Everything else is about right - 41 screen voltage is at 226 VDC (should be 220). 84 rectifier cathode is at 290vdc on the nose. 4 uf C30 is at 220vdc and 2 uf is at 196vdc. For C31 between 10uf and 12 uf it read 290VDC and between 12 uf and black (neg) it reads 304 VDC.
What is making that plate voltage on the 41 output run so high? If there is hum from the speaker, does that mean the output transformer is still ok? This is a chairside - so the speaker is a S19 - In the below, the new green wire goes to field coil yellow new white to terminal on the output transformer (now I am thinking this may be wrong given my issue with the excessive voltage on 41's plate) and new black to the black from the field coil. -- Andy
Everything else is about right - 41 screen voltage is at 226 VDC (should be 220). 84 rectifier cathode is at 290vdc on the nose. 4 uf C30 is at 220vdc and 2 uf is at 196vdc. For C31 between 10uf and 12 uf it read 290VDC and between 12 uf and black (neg) it reads 304 VDC.
What is making that plate voltage on the 41 output run so high? If there is hum from the speaker, does that mean the output transformer is still ok? This is a chairside - so the speaker is a S19 - In the below, the new green wire goes to field coil yellow new white to terminal on the output transformer (now I am thinking this may be wrong given my issue with the excessive voltage on 41's plate) and new black to the black from the field coil. -- Andy
Andy Sorrell
Palmyra, Virginia
