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Accuphase E-302 Help Needed

You are right @KentTeffeteller !
I contacted Accuphase and they replied immediately that they cannot support me. Even more, they contacted me a few days later suggesting a repair service nearby. For this, hats down - nice customer support! Unfortunately not what I need.
 
Tala Mink said:
Kta1381 & Ktc3503 are the most similar 2SA1360/2SC3423 replacements that are currently available.

Also the symbol underneath D12 looks like one for a zener diode.

Id remove D12 from the working channel and check if its a zener before putting a standard diode in.
Click to expand...
Hi @Tala Mink

Do you have a source for these two transistors?
I struggle to find any from reputable sources. Only eBay and Aliexpress (probably the same). And tbh I am not a fan of them both.
 
you can buy them directly from Profusion KTA1381 KTC3503 but you will have to pay $15 for delivery and a $15 transaction fee to in addition to tariffs if you are in the us.

Your profile says your in Switzerland so I hopefully you only have to pay shipping.

If you buy from ebay, the ones from the seller Affinity For Artifacts are real.
 
Thanks @Tala Mink !
I am trying to source them from Europe. But if not possible I will go for the shop you mentioned. These are not so old, so I believe I should be able to get them here.
 
Guys, I was able to buy some 2sa1360 from a shop which is reputable, I believe.

IMG_8195.jpeg
But what I got is a bit different. Do you think this is a legit component? It’s black and smaller.
 
Hi guys,

A quick update: so I replaced the blown A1360 with the one from the picture above, but I was still getting some bright light from the DBT and replaced it again with an A1381. Still not OK... Then I checked all the output and driver transistors again and they measure OK, also compared them with the ones from the left (healthy) channel. Checked all diodes and they are OK, then started checking the smaller transistors on the board. And found out that Q11 was gone. Actually this was directly connected to the emitter of the A1360 and the blow resistor Replaced it and went on to check all the other small transistors - all measured OK. When powered on again some indications of a short at the DBT. When I remove the right channel the DBT almost goes completely dark. This tells me there is something wrong with the right channel. Then I replaced the capacitors and they all measured OK too. Also checked the bigger resistors...
Also, what is interesting is that I can hear two relays engaging. But at the same time I cannot get any sound from the Accuphase. I even injected sound directly into the Mains-In and again no output with and without the right channel.

Any SUGGESTIONS PLEASE! As I am currently out of ideas.

What could cause this strange behavior?

Thanks in advance!
 
Ok today I was able to dig deeper into the E-302.
I was checking the voltages and came out I am missing the DC -72 volts. I checked the preamp board and then the power supply board. Comes out someone was already at the PS replacing the capacitors. But what was worse is that two of the boars lines were almost evaporated.
IMG_8336.jpeg
And these were exactly going to the -72 dcv. I reworked these and also replaced the caps as the ones in were for 25v. I used 3300uf/85v. These should work well I believe.
IMG_8341.jpeg
After power on I am able to get some sound but I have another issue:
After a few seconds relay3 starts oscillating. This relay is at the headphones muting board (I believe).

This happens with the right channel connected (the defective one). The relay kicks in and out and the vu meter jumps a lot. I can hear sound but really cutting off and the relay oscillates.

Guys, what could be causing this oscillation?

On another note, comes out there might be an issue on the left channel too as the protection is not allowing activation when left channel is connected. But this problem will be for a later stage, I believe.

Thanks in advance for your help!
 
Resolved!
The e-302 is now performing as expected. Sounds really, really nice!
Two important facts to report: the A1381 is not a good fit for this amp. Went back and replaced it with the NOS A1360 and things worked fine. Second, the UF4005 is not a good fit for D12 position on the amp board. It was causing oscillation. So I used 1N4148 and this fits fine.
There was also an issue with the selector switch at the back (normal/separate) for the decoupling of the pre- and main- amps. With age this has developed rust, I believe, and was not passing signal through. Some DeoxIt and wiggling left-right fixed it.
I will now finalise the recapping and then enjoy the Accuphase E-302.
I hope this thread will help someone in the future as it is difficult without a schematic and SM.
 
Another update: actually for d12 I used bzx85c12. Also replaced the incandescent lamps with warm white LEDs.
Set the bias to 11mV (seen or read somewhere that this is the correct level)

IMG_8425.jpeg
 
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