Boston Acoustics Plate Amp Troubles

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Hi,
So I have this Boston Acoustics plate amplifier from a CR400 subwoofer. It WAS working (though seemed weaker than I remember it being) so I recapped it since several caps tested out of spec. After recapping it, I fired it up on my DBT with a 40w bulb. The bulb was somewhat bright, but not fully lit. Smoke shortly started rising from the amp board.


Resistor R121 was the one that smoked the most, and in 2nd place is R122. 1 leg of R122 and 1 leg of R122 are tied together and connect to a capacitor (C115) and a resistor R119.

The other end of R121 connects to the emitter on Q102 (D1563A), and the other end of R122 connects to the emitter on Q103 (B1086A)

The fact that these resistors burned up I’m guessing means those transistors are likely shorted (wonder how I did that) Where would I find replacements/drop in substitutes for these transistors (2SD1563A and 2SB1086A) and how do I figure out what actually killed them. I think they are driver transistors (right before the output transistors) but how do I go about this? Do I start pulling transistors and testing them for shorts/open circuits? I’m trying to avoid soldering as much as possible since the board traces are really fragile (cheap board too) Do I start by testing the outputs and work my way down? If the outputs need replacing, where can one obtain a replacement or substitute for 2SB688 and 2SD718. Boston doesn’t share schematics with customers and the service centers don’t have access to old schematics (this CR400 had a 1998 build date)

I'd like to actually learn and fix the problem (not throwing parts at this) so I need help and advice on how to troubleshoot. It's not the end of the world since it's just a plate amp and replacements are cheap but I'd like to learn. The photos show the resistors, etc. I have 2 of these amp boards (tried fixing a broken 1 I found on ebay a few years back with no luck. Whoever BA contracted production and design of this amp to seems like they used the same board in other designs since a lot of the board is not populated. I did try to remove the conductive/corrosive glue and replace some corroded components. The 4558 op amp probably should be replaced judging by the corrosion on the pins.
 

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Start by checking the output devices and driver transistors. Do this in circuit with your meter set on diode check. Base to emitter and base to collector forward voltage should be around 0.6V in one direction only. I suspect you will find some shorted devices. It's a lot easier to repair the amp if you can find a schematic for it. Reverse engineering it is possible but much tougher to do. I see in your fourth picture you have screwed a clamping plate to some output devices. Did you try to run the amp like this?
 
I had the sub screwed to the plate with thermal pads and all. Made sure the outputs weren’t shorted to the chassis (plate)

You see it in the photos since I didn’t want to lose the hardware. I’ll start by checking the outputs for shorts, then the drivers and will report back.
 
Replaced the transistors, but after rereading EchoWars Testing a transistor, the outputs seem fine, to I reinstalled them. One of the driver transistors tested open. Replaced both drivers, and all of the other semiconductors on the board. The resistor STILL smokes. With the preamp board connected, and the OFF-Auto-ON switch in off, nothing happens. The DBT's 40W light glows brightly for a second, then dims down (very dim), and then when I turn the switch on, the bulb glows slightly brighter (still quite dim), the relay clicks, and R121 begins to smoke. :( No schematics for this old unit through BA. Anyone else have advice?
 
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