Kudos to you for some really good detective work IMO. I replaced both 10k resistors on the PB-1314A regulator board (one on each side of the bias adjustment pot) after trying to track down a run away oscillation problem which red-plated the finals whenever flipping the heater switch on. Turned out to be the bad 82pf mica coupling cap between the driver & finals, which I replaced with a new one from eBay, 82pf@1KV. It failed too in a couple days, over heated the reg. board resistors again & cooked a nice set of Toshiba 6SJ6C’s because I wasn’t paying attention & red-plated them. So changed the 82pf again with a brand name one this time from either Mouser or GigiParts @2kV, & new 10k resistors but went up to 1/2 watt resistors this time, & an old set of finals to check for the correct voltages on all the PA tubes’ pins on the sockets underneath and voltages on the reg board at the bottom where the board plugs into the long socket- no more red-plating the finals with heater switch on. Also used a recap kit on the regulator board. Using american 6JS6C’s, & was able to cold neutralize them without replacing the 100pf mica neutralizing cap on this particular rig, an FT-101EX. It works now, lol. GL- enjoying your videos! 73, W8SOO Ken
Kudos to you for some really good detective work IMO. I replaced both 10k resistors on the PB-1314A regulator board (one on each side of the bias adjustment pot) after trying to track down a run away oscillation problem which red-plated the finals whenever flipping the heater switch on. Turned out to be the bad 82pf mica coupling cap between the driver & finals, which I replaced with a new one from eBay, 82pf@1KV. It failed too in a couple days, over heated the reg. board resistors again & cooked a nice set of Toshiba 6SJ6C’s because I wasn’t paying attention & red-plated them. So changed the 82pf again with a brand name one this time from either Mouser or GigiParts @2kV, & new 10k resistors but went up to 1/2 watt resistors this time, & an old set of finals to check for the correct voltages on all the PA tubes’ pins on the sockets underneath and voltages on the reg board at the bottom where the board plugs into the long socket- no more red-plating the finals with heater switch on. Also used a recap kit on the regulator board. Using american 6JS6C’s, & was able to cold neutralize them without replacing the 100pf mica neutralizing cap on this particular rig, an FT-101EX. It works now, lol. GL- enjoying your videos! 73, W8SOO Ken
Just watching , mine had no IC , have got it going now so be interested to see what your issue is ..