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Denon PMA-900V Troubleshooting

Awesome, thanks! I was searching a few sites and threads for equivalents to the originals but wasn't really sure what is good or bad for replacements. What about the TR509?
 
Okay, I'll order the parts from Digikey and then the one above from Mouser with the compliment MJE15032G. Few things before finalizing each purchase:

1. Please confirm this is correct for the MJE15032G: https://www.mouser.com/ProductDetail/863-MJE15032G/

2. Should I order replacements for the 4.7ohm resistors for this channel since they're already out of the board? They tested fine but if a few extra $ for new ones improves future reliability I'm all for it (considering most items around these on the circuit were wiped out).

3. The original 2SA1106 had metal case back, the 2SA1695 replacement from digikey does not appear to have the metal case back...is the 2SA1695 still good for order?

4. Not sure what this light blue tape type material is that was sandwiched between the heat sink and transistors, do I need to order something to replace these square tabs (in the original pic I loaded you can see them)?

5. Any other recommendations to add to the order?
 
Beavs said:
the 2SA1695 replacement from digikey does not appear
Click to expand...
Look at the spec data sheet... Yes its a SANKEN TO-3P/MT-100 ? Same as the original transistor -- The photo is a bogus stock photo.. These are exact replacements..

Get the Onsemi MJE's at Digikey as well.. Save shipping cost from Mouser..
avionic said:
Digikey likely has the MJE15033G's as well .. I'd replace its compliment as well TR507..MJE15032G
Click to expand...


2SA1695 data sheet

https://www.semicon.sanken-ele.co.jp/sk_content/2sa1695_ds_en.pdf
 
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Shoot, got another question. Image below is of TR508 but it's the same as TR507. They both have a wire lead to the top of the case throughhole with some white doping. No idea what that is, is this an adder to the order?
 

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Beavs said:
Shoot, got another question. Image below is of TR508 but it's the same as TR507. They both have a wire lead to the top of the case throughhole with some white doping. No idea what that is, is this an adder to the order?
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Going to have to provide a better photo than that..
 
Beavs said:
Shoot, got another question. Image below is of TR508 but it's the same as TR507. They both have a wire lead to the top of the case throughhole with some white doping. No idea what that is, is this an adder to the order?
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The wire is likely connecting the TO-220 metal tab (collector) to a remote location on the circuit board.
 
Getting the camera to focus was a pain. Hopefully these work better for pics. The white stuff is still liquid, accidentally touched it when desoldering and lifted that drip tail off of the glob over the wire lead. BTW, you'll see in this pic that TR512 (2SC2581) had been replaced at some point and whoever did it clipped the legs instead of desoldering from the board. I was going to order an extra to replace that even though it tested out fine.

Regarding the metal jacket question for 2SA1695, thank you for the clarification, I assume there is something that indicates this on the datasheet but it was not apparent to me when looking at it (stock photos not to be trusted, noted).

Added the Onsemi MJE's to the Digikey order.

upload_2021-1-13_20-49-19.pngupload_2021-1-13_20-49-52.png
 

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Wipe off the heatsink compound. I suspect a thermal tracking diode is in physical contact with the metal tab.
 
Beavs said:
4. Not sure what this light blue tape type material is that was sandwiched between the heat sink and transistors, do I need to order something to replace these square tabs (in the original pic I loaded you can see them)?
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Some kind of Kapton tape to isolate/insulate the metal backing of the SANKEN's from the heatsink ( chassis ground )

Replace with mica insulator and new heatsink compound.


Mica insulator
https://www.digikey.com/en/products...ivision-of-boyd-corporation/56-77-11G/1625385
thermal compound 2 packets will be more than enough.
https://www.digikey.com/en/products...4WlQCcrDt0ggp0yhs4ALXAIC2WAARIi19kQCuIgCatJQA
 
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Holy shite! Kapton tape 1" width, cheapest I find is $19.65 for 100ft on digikey, Amazon has it for much cheaper. Amazon made in china stuff okay for this? I could just use the old tabs that I pulled off but part of them stayed adhered to the heat sink.

D531 on the schematic is what the lead wires of this are connecting to TR507. Pic without doping and D531 part number from service manual:
upload_2021-1-13_21-44-56.png


upload_2021-1-13_21-45-17.png
 
Looks like I responded about the kapton tape before your post came through. Mica and thermal compound will be added. Last remaining thing was me wondering about whether or not the 4.7ohm resistors should be replaced since they are right in the middle of these other fried components.
 
Beavs said:
PE9ZZ - I'm unclear on what direction you are advising. It reads as though I would power up with DBT after pulling the transistors out of the circuit...is that right? I think you're meaning to replace any bad transistors after pulling and testing, then DBT but just making sure. Also, shorting the base and emitter pads of any given transistor, is this just to be done prior to testing them out of circuit?
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What I'm trying to convey is that you can check the circuit without the output transistors in place. This is useful because if you replace them and the driver has gone phut (which in your case it has) you will have to buy new ones again. So what you do is remove the output transistors, all of them, and short one pair of base and emitter pads on the board. Just one of them, any one. This way you can test the amplifier without any power transistors at risk of being destroyed (or a DBT going full on). In your case TR509 has gone phut too and you must replace it first in order to successfully perform the driver test. Of course you cannot put a load on the amp in this stage. Headphones will work though.
 
PE9ZZ said:
What I'm trying to convey is that you can check the circuit without the output transistors in place. This is useful because if you replace them and the driver has gone phut (which in your case it has) you will have to buy new ones again. So what you do is remove the output transistors, all of them, and short one pair of base and emitter pads on the board. Just one of them, any one. This way you can test the amplifier without any power transistors at risk of being destroyed (or a DBT going full on). In your case TR509 has gone phut too and you must replace it first in order to successfully perform the driver test. Of course you cannot put a load on the amp in this stage. Headphones will work though.
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I've never shorted anything like that. A while back someone also suggested putting 470ohm resistors between a couple of the pads (same ones) to test without outputs.
With many amps you can get sound and relay click with no outputs installed without doing anything.

I just test thoroughly and power up with DBT and new outputs. VERY rare I blow new outputs even when I miss something.
If I really want to be extra careful I'll use the variac.
 
Raccoon1400 said:
I just test thoroughly and power up with DBT and new outputs. VERY rare I blow new outputs even when I miss something.
If I really want to be extra careful I'll use the variac.
Click to expand...
There are many ways to achieve the same goal. With this easy strategy you can quickly verify if your thorough testing was sufficiently thorough.
 
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