Hi
I recently bought a PL400 needing attention. One channel has original drivers and outputs (RCA 410 and XPL909). The other channel has some different components - Drivers are SJ2741 and the outputs are a mix of four PL909 and two MJ15024 - not good.
Arrived with no main fuse. On DBT (with fuse) it draws too much current. Measurements indicated that three of the connected outputs on one channel were conducting C-E (one measured alright out of circuit). Unsurprisingly, these were on the channel with mixed output devices. With the three removed, the current draw looks normal on DBT.
It looks like I can fix the amp by replacing outputs on the on the bad channel. It looks like I would need four PL909 to do this. They don't appear to be easy to come by. Also, the XPL909 on the good channel have green writing, which I have read is a bad sign.
There are threads that suggest that MJ15024 or MJ21195/MJ21196 can be used as outputs. But it also looks like the choice of outputs may depend on whether the circuit in the PL400 is full complimentary or quasi complimentary. The PCB in my amp appears to be the PCB 14A type.
I would appreciate it if someone could tell me whether the amp is full or quasi complimentary and whether there is a commonly available output device I could use. This may be crazy-talk but the 2N3055 is cheap and convenient to get and looks like it might be compatible, save for the low VC of only 100V.
Any suggestions?
Thanks.
I recently bought a PL400 needing attention. One channel has original drivers and outputs (RCA 410 and XPL909). The other channel has some different components - Drivers are SJ2741 and the outputs are a mix of four PL909 and two MJ15024 - not good.
Arrived with no main fuse. On DBT (with fuse) it draws too much current. Measurements indicated that three of the connected outputs on one channel were conducting C-E (one measured alright out of circuit). Unsurprisingly, these were on the channel with mixed output devices. With the three removed, the current draw looks normal on DBT.
It looks like I can fix the amp by replacing outputs on the on the bad channel. It looks like I would need four PL909 to do this. They don't appear to be easy to come by. Also, the XPL909 on the good channel have green writing, which I have read is a bad sign.
There are threads that suggest that MJ15024 or MJ21195/MJ21196 can be used as outputs. But it also looks like the choice of outputs may depend on whether the circuit in the PL400 is full complimentary or quasi complimentary. The PCB in my amp appears to be the PCB 14A type.
I would appreciate it if someone could tell me whether the amp is full or quasi complimentary and whether there is a commonly available output device I could use. This may be crazy-talk but the 2N3055 is cheap and convenient to get and looks like it might be compatible, save for the low VC of only 100V.
Any suggestions?
Thanks.