Recapping of Marantz 2275

[sanjib]

That should be ok.

Never saw an 85w incandescent bulb though (Usually 60/75/100 were most common).

If you have time over the weekend ,since you're ordering and waiting for new outputs,it wouldn't hurt to check your driver transistors and the emitter resistors.
What are you using to test transistors?

Bob

I know H713 and H714 are the driver transistors, which ones are the emitter resistors R740?

 

[sanjib]

R740 is actually two resistors 0.2ohm 5W connected in series between emitters of driver transistors. Is that one you referring to?

 

[Steven Tate]

yes, those are the emitter resistors.

 

[sanjib]

yes, those are the emitter resistors.

Thanks Steven!

 

[sanjib]

yes, those are the emitter resistors.

These are just 0.2ohm! Can I measure it with my mutimeter correctly?

 

[sanjib]

Without taking it out from board it is showing short in my multimeter! I will take it out and measure.

 

[wlhd1610]

Sorry , been out mowing.
.2 ohm is so low your meter probably won't be able to test them.
Leave them be for now.

You can compare "in circuit" to the good amp module for relatively similar readings with both modules sitting loose on bench if you'd like to root around (powered down,of course)
Bob

I know what it's like to need a timely answer.
I'll pm my phone number.

 

[sanjib]

Sorry , been out mowing.
.2 ohm is so low your meter probably won't be able to test them.
Leave them be for now.

You can compare "in circuit" to the good amp module for relatively similar readings with both modules sitting loose on bench if you'd like to root around (powered down,of course)
Bob

I know what it's like to need a timely answer.
I'll pm my phone number.

Bob: Each resistor at R740 measures 0.27 ohm. Both driver transistors are ok. Both of the output transistors showing shorts between all leg combinations.

 

[sanjib]

I think I will just wait for new output transistors to come and install it when arrives!. Should I also change the working output transistors in the other channel with the same replacement?
Thanks

 

[wlhd1610]

I would leave them.
Especially if they're original Marantz labeled.
Not so much if they're the Sylvania branded ones or NEC though.


Bob

 

[sanjib]

I would leave them.
Especially if they're original Marantz labeled.
Not so much if they're the Sylvania branded ones or NEC though.


Bob

It is labeled "Noble"

 

[wlhd1610]

It is labeled "Noble"

Let's see a pic

 

[catrafter]

Noble can be OEM.

Tom

 

[sanjib]

Noble can be OEM.

TomView attachment 1543448

Yes, this one! Reading was fluctuating between 0.26 and 0.27

 

[wlhd1610]

I think I will just wait for new output transistors to come and install it when arrives!. Should I also change the working output transistors in the other channel with the same replacement?
Thanks

I would leave them.
Especially if they're original Marantz labeled.
Not so much if they're the Sylvania branded ones or NEC though.


Bob

I thought you meant the output transistors.

Sorry ,my mistake.

Bob

 

[sanjib]

I thought you meant the output transistors.

Sorry ,my mistake.

Bob

Never mind! I will reinstall this one. I will change the bad output transistors in one channel. Should I replace the working ones (they are S40442/S40443) in the other channel with the same replacement?

 

[sanjib]

I have completed my Marantz 2275 project! Thank you all for your help without which it would have too difficult for me to finish this. So both amps, phono, power supply, and preamp boards are fully restored! Here are some pics of the restored sections!
Thank you to everyone for your help especially Bob and Tom!

 

[wlhd1610]

Good job!
Perseverance pays off!!


Bob