Hi All,
Joined the forum a few days ago and have been reading and educating myself. Lots of great info. I have a PL 400 I bought new in 1978, while stationed in Wildflecken, Germany in the Army. Purchased at the Audio Photo Club. Had it repaired once in the 80’s at a shop in CA. It’s been sitting in my basement for 10 years since it started blowing the 5A supply fuses. Started up my basement as a man cave, so thought I would revive all my old equipment, just rebuilt my ESS AMT monitors. I bought an output relay speaker protection kit from wattsabundant. But before I install I think I need to replace some or all the output transistors, both channels are vaporizing fuses. The repair I had done in 80 they replaced 4 transistors, two of them were Toshiba 2SD371, the other two PL909 (i didnt know this then). Anyway looking for advice, should I replace all 12 of the output transistor PL909 and the 4 driver outputs RCA 66546? I followed the instructions in the service manual and ohm’d out each transistor. Column 1 and 2 the PL909 were 10.8 and 11.3 ohms. Column 3 and 4 which had replaced transistors were all about 1 ohm. The driver transistors ohmed out at 211, 242, 278 and 351 ohms.
Joined the forum a few days ago and have been reading and educating myself. Lots of great info. I have a PL 400 I bought new in 1978, while stationed in Wildflecken, Germany in the Army. Purchased at the Audio Photo Club. Had it repaired once in the 80’s at a shop in CA. It’s been sitting in my basement for 10 years since it started blowing the 5A supply fuses. Started up my basement as a man cave, so thought I would revive all my old equipment, just rebuilt my ESS AMT monitors. I bought an output relay speaker protection kit from wattsabundant. But before I install I think I need to replace some or all the output transistors, both channels are vaporizing fuses. The repair I had done in 80 they replaced 4 transistors, two of them were Toshiba 2SD371, the other two PL909 (i didnt know this then). Anyway looking for advice, should I replace all 12 of the output transistor PL909 and the 4 driver outputs RCA 66546? I followed the instructions in the service manual and ohm’d out each transistor. Column 1 and 2 the PL909 were 10.8 and 11.3 ohms. Column 3 and 4 which had replaced transistors were all about 1 ohm. The driver transistors ohmed out at 211, 242, 278 and 351 ohms.
