Marantz Model 4300 needs help

Yes i put the details above.

Right Side
SJ2517
SJ2518
2SC1403
A475
All tested good with no leaking with 33-100 gain.

Left Side
2SC1403 ( Failed )
2SA745 ( Failed )
SJ2517
SJ2518

Which is were the other failed parts are.

And thank You.
 
2SC1403
2SA745
are listed as correct ones .
just researching ..subs . on semi are good . i only have old sub list and not found a pair yet .
 
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Well was thinking of just replacing the caps on the power board (P800) and sound boards (P700) and any thing else that was recommended.

I am after the 2 transistors (2SC1403 + 2SA745) and the following.

R742 (100Ohm 5% 1/2w
H715 D357
H716 B527

And be nice to replace undocumented resister between H730 & H718, which all i know is 50Ohm ( if memory serves).
 
you should at least replace all outputs in blown channel ... working channel should be fine ..so long as those sj ones are suitable .. cant find any reference for those with this unit ..
 
Well i found the parts just waiting on them to get here, should be no llonger than a week. Going go though the thread at least one more time and go though though the tests again as i cannot keep throwing money at it and actually think they are original parts that are being sent. I guess we will see.

Hopefully they all work when i get them.

The burned out resister could that of been due tot he transistor failing ? (D357 Or B527). Just trying to get more of a idea what happened and why it failed.

There is another resister but i cannot find it in the service manual, i have asked about it but no ones responded about it.
 
H715 D357 (Short B+E)
H716 B527 ( short B+E)

R742 failed open

Unknown resistor ( working but burned ( 50Ohm )
rster252.png
 
yes its something to do with those transistors shorted . b to e short is unusual but can happen . did you confirm the shorts out of circuit ?
i would like to know id of unknown resistor .. can you figure out what each end connects to ?
 
Yes i checked were the old transistor were and short as gone in both cases

Spent a little more time with it and found another short :(, 2SC458 on the same side is all so shorted,i noticed it was their and missed it ^^, so compared with other board and channel and it's surly only one that shows a short. Will have to pick one of those up now to but the guy i got the other stuff of is away until the 20th :(. Once i get the part i will check if the short goes their too when removed.

I got the unit for $50 so don't mind dropping some money on it as it seems like i could make it back anyways.
 
Here's a closer pic of that burned but working resistor and the other from the other channel.

imgp9278.jpg

imgp9279.jpg


keep checking .. the thing is when in circuit one shorted component can make others appear shorted

I have taken out all the other transistors and they tested all good.
 
Just after a 2SC458,anyone know were i can get one ?, Well i do need the string if anyone has any idea's.
 
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