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Accuphase E202 Power Supply Transistor

C

Champ

Active Member
Hello, I am looking to replace a 2SA682 and a 2SA1382 on my Accuphase E202 power supply board.
Can anyone direct me to good equivalents. They are Q9 and Q10.

Although I do not have any issues with the amp, there is a discolouration on the board and thought perhaps replacing these transistors may give me some longer life.
Any other suggestions as to replace other components.? Perhaps up the wattage of the wire wound resistors to 5 watts. All electrolytic were replaced.
 

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For the age of the amp, the discolouration is minimal - if the amp is working normally, I'd leave the original transistors where they are. You could clean the area, and maybe add a little thermal compound between the heatsinks & the transistors, but it certainly doesn't look bad, at least not in my opinion.

I assume the resistors you're referring to are R27 / R28 ? If so, then again, they don't appear distressed to me, and I don't really see any benefit to changing them - they are dissipating ca. 1.4W (of heat) each according to the schematic values, so will be hot, but will continue to dissipate the same whether they are 2W or 5W items.

If the recapping has given any additional 'free space' in that area (?), then obviously position the components for maximum airflow / cooling - I assume the photo is before recapping, so it's harder to judge.
 
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Peruse this thread: http://audiokarma.org/forums/index.php?threads/accuphase-e-202-cap-list.732412/

You can also sub a TO-220, but it has to be mounted on the other side of the heatsink (and the STV diode moved to the back of the board):

2025_zpskkxjhrwa.jpg~original


2026_zpswql4w1o0.jpg~original
 
EchoWars said:
Peruse this thread: http://audiokarma.org/forums/index.php?threads/accuphase-e-202-cap-list.732412/

You can also sub a TO-220, but it has to be mounted on the other side of the heatsink (and the STV diode moved to the back of the board):

2025_zpskkxjhrwa.jpg~original


2026_zpswql4w1o0.jpg~original
Click to expand...

When I get a moment tomorrow I'll take a closer look at this above mentioned thread. I just installed new Nichicon KG main filtering caps on this beast tonight and that just about did me in for one day. She up and running though and sounding sweet.
 
EchoWars, it seems to me, after reading the other thread that your advice is to leave well enough alone unless there are know potential issues. Such as the "2SC1451's gotta go". So., perhaps I should star there and relate with your recco of 2SC3902T. The 2SC3902T is for heatsink application. Would I need to attach to some kind of heatsink?
 
Goldie99 said:
For the age of the amp, the discolouration is minimal - if the amp is working normally, I'd leave the original transistors where they are. You could clean the area, and maybe add a little thermal compound between the heatsinks & the transistors, but it certainly doesn't look bad, at least not in my opinion.

I assume the resistors you're referring to are R27 / R28 ? If so, then again, they don't appear distressed to me, and I don't really see any benefit to changing them - they are dissipating ca. 1.4W (of heat) each according to the schematic values, so will be hot, but will continue to dissipate the same whether they are 2W or 5W items.

If the recapping has given any additional 'free space' in that area (?), then obviously position the components for maximum airflow / cooling - I assume the photo is before recapping, so it's harder to judge.
Click to expand...
Points taken, thank you.
 
Would it be a good idea to replace the 1S1555 Diodes on the PS at this point to? Perhaps with 1N4148's. These are the closest match I can find.
 
I'd say no. The originals are not known to be problematic. I'd leave them be unless you find that they really need replacing.
 
I'm leaving em. After a recap and some transistor replacements, any recommendations on what else maybe done to this machine. I think I may have maxed out on it. She sounds amazing.
Wide, deep soundstage, instruments and vocals nicely placed in their own space. I am very impressed. The cap replacement was a big improvement.
 
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Sorry to resurrect this old thread, but I have a question regarding this post. Now, I understand why you'd place the TO-220 transistor on the back of the heatsink, but what is the reason for moving the STV diode to the back of the board?

EchoWars said:
Peruse this thread: http://audiokarma.org/forums/index.php?threads/accuphase-e-202-cap-list.732412/

You can also sub a TO-220, but it has to be mounted on the other side of the heatsink (and the STV diode moved to the back of the board):

2025_zpskkxjhrwa.jpg~original


2026_zpswql4w1o0.jpg~original
Click to expand...
 
Ok, I just got done doing a complete recap and restoration of my E-202. The answer to my question above becomes obvious once you take a look at the position of the reversed transistor placed onto the back of the heat sink. There's no room for the diode so you have to put it on the bottom.

I wanted to show my experience that gave me a bit of grief while doing my restoration. I had the hardest time figuring out why the relay would turn on instantly after turning it on. The problem turned out to be a bad diode on the power supply/protection board. D6 was shorted. I popped in a 1N4148 and the relay kicked in after 4 seconds. I haven't listened to it yet, but all the voltages check out and it looks good on a scopel
 
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