Pioneer SX-1250 AWH-048A amp transistor sub list?

CrashRash

SpeakerWorkshop dude
Hi folks,
Well this my first post, so, first- thanks for letting me join the group and two- I apologize in advance if what I am posting is redundantly posted elsewhere.

I am working on a Pioneer SX-1250 receiver that has seen the hand of an unknowledgeable tech or DIYer. It as a power amp problem with several blown components.....problem is they replaced most of the transistor with ECG or NTE devices and other that do not have the same specs as the OEMs. I've systematically tried to find the OEM devices but have mostly struck out, so I was wondering if someone has a good, available substitute transistor list for all of the transistors on the amp board (AWH-048A) and the outputs (While we are at it...."correct" sub for 2SD555 and 2SB600).

Thanks.
Crashrash
 
Welcome to Audiokarma!! Pioneer Audio Forum !! :bigok:

2sb600 pnp to-3 200v 10a 200w 20-200Hfe 4MHz
2sd555 npn to-3 200v 10a 200w 20-200Hfe 7MHz

........534-4662 to-3 mica insulators $0.16 each.................
863-MJ21193G pnp to-3 250v 16/30A 250W 8-75hfe 4mhz $4.07
863-MJ21194G npn to-3 250v 16/30A 250W 8-75hfe 4mhz $4.07

at mouser.com

for the rest, see the last posts in this thread
 
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Reading through the posts I see part locations labeled like q1 or q2 and stuff like that. I'm new to this and would like to know where is the diagram that shows me what is what? Thanks in advance!
 
"Q" represents the transistors. Look at the parts break down in the Service Manual (SM) and you will see all the designations for the different components. Study the SM and locate all the transistors on the Amp board. This way you will have a better understanding of the layout. The SM board image is viewed from the back (Trace) side, so the actual top side is a mirror image. You'll get the hang of it.
 
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Reading through the posts I see part locations labeled like q1 or q2 and stuff like that. I'm new to this and would like to know where is the diagram that shows me what is what? Thanks in advance!

You should move your thread (probably just start a new one with what you posted in vintage solid state) about your blown amp board over here, in a NEW thread - yes - I checked - and you haven't yet. After you start the thread I will make a copy of this post and it's information in the new thread.

THIS (in your own thread) is where you will get the most effective help. INCLUDING parts sources and parts numbers in a literally cut and paste format.

With all the blown resistors I see on the board, you are going to need plenty of help, mostly in parts numbers, which are ALREADY known and researched. You blew some of those 0.5 ohm 5 watt big white rectangular resistors, and that caused the flameout of the 4 resistors in a row you featured in one photo. Almost every medium to high powered transistor in that channel including the outputs IS fried, and those that survived, were racing to destruction, are damaged, and should be replaced to avoid a re-run of the fireworks when you turn it back on..

As to why - you probably broke the thermal bias diode wire - on both pictures the second wire's hole is unpopulated - and if the wire is busted off at the diode, you are either going to have to find another (we call them unobtanium) - or send it to me for grinding and flexible lead replacements (I have a "service" that repairs these parts FRAGILE wires).
 
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