Accuphase E-202 restoration

[reddish75]

So Auralflea (Kevin) contacted me about restoring this Accuphase E-202 and i thought it would make a good thread about restorating a pretty fucked up amp back to its former glory.

Properly restoring an amplifier isn't just a case of recapping it and setting the offset and bias its much more involved:-

A complete recap
All zener diodes replaced
Any out of spec transistors or any that have known problems replaced
Any out of spec or stressed resistors replaced
Adjustment pots replaced with sealed multiturns
All boards defluxed and cleaned
All switches and pots cleaned with deoxit
All solder joints inspected anf resoldered if needed
Probably a couple more i can't think of at the mo.

This amp had been with another tech for around six months with an apparent switch fault, which he could'nt rectify. Seems that it had been with a 'tech' for a while i thought the rest (not the switch) would be in tiptop shape, how wrong was I, after further inspection i have found dozens of resistors with cracked insulation only a handful of original transistors and a couple of bodged amutuer repairs.



heres some pic's and comments.....




At first glance nothing looks to off, standard japanese layout and component choices, grey Elna caps etc.



Starting to see things that arn't original, the most obvious being the RS rectifier which has replaced the original rectifier pcb. As you can see its been installed in a pain in the arse place and the pins on the big psu cap underneath have been bent to accomadate it, pretty shoddy soldering as well.



More worring soldering (Just tagged on the pins) on the circuit breaker.



Psu circuit board



The irreplacable STV diodes have been moved to the back of the board.

Poweramp board

[Teti]

Great job indeed! How long did it take?

[enbee23]

Great job indeed! How long did it take?

I think we're still at the "before" stage.

Very much looking forward to see how this works out, I have a couple of related boxes here that might benefit from similar attention.

[auralflea]

I am a bit taken aback to see how much this amp had been fiddled with previously, although being some 40 years old or so I shouldn't be too surprised.


Looking forward to the updates as you go Chris, and really looking forward to hearing the end result!

[earlofsodbury]

Huge respect to Chris for taking this on - these are complicated amps with many hard-to-find components, and this is one job I refused (sorry Kevin) - looking at the issues you've found, I don't regret that decision one little bit! (sorry again Kevin! )

I'll watch this thread with interest! Best of luck

[auralflea]

Huge respect to Chris for taking this on - these are complicated amps with many hard-to-find components, and this is one job I refused (sorry Kevin) - looking at the issues you've found, I don't regret that decision one little bit! (sorry again Kevin! )

I'll watch this thread with interest! Best of luck

As I recall it, you declined the job before I even asked!! Not that I blame you at all, this looks to be a seriously time-consuming job ahead for Chris.

[James Evans]

Blimey, respect Chris. I wouldn't fancy that! Just recapped my AI Alto yesterday - smallfry in comparison!

[THOMO]

I bought one of these and the preamp/power amp selector has been bypassed so I cannot use them separately.
The switch must be buggered.
Any ideas on the best way of restoring this function?

This one has been reconditioned.It seems all the electrolytics have been replaced with Rubicons.Power supply caps are RS Components.
Also the left hand side near the front has had a grid pattern of holes drilled in it.Obviously overheating here was a problem.

It sounds very good.Certainly the best integrated amp I have used.
A classic combination with Gale 401 speakers.

[reddish75]

New switch? Should beable to buy one from Rs, if not take the switch out and join the rca's with phono lead you can then use them seperatly if you know what i mean.

[reddish75]

The mouser order turned up, 112 different components some with multiples of the same.....



Never before have i had to change so much inside an amp but, this thing is so far gone needs must. Some compromises i have had to make are using radial caps (panasonic FC/FM) instead of axials as the quailty and performance is much better and using different resistors than i would normally (i usually use vishay rn's) simply because of the large number that need replacing.

Now the work begins!

[earlofsodbury]

[auralflea]

[reddish75]

A quick update as now back off annual holiday, Psu regulator card has almost been completed just waiting on a few missing parts to turn up. As you can see only 3 original transistors have survived the hacked attemps of repair, the replacements have been replaced with correctly crossreferenced parts, also i dont know whats happening with the resistors in this amp but the enamel is shrinking/cracking on nearly all of them, poor quality maybe?

[earlofsodbury]

A quick update as now back off annual holiday, Psu regulator card has almost been completed just waiting on a few missing parts to turn up. As you can see only 3 original transistors have survived the hacked attemps of repair, the replacements have been replaced with correctly crossreferenced parts, also i dont know whats happening with the resistors in this amp but the enamel is shrinking/cracking on nearly all of them, poor quality maybe?

Hope you're going to do something about the heatsinks on those regs! Might just explain the cracked R...

Actually I've just started a similar but less daunting job on a Meridian 200 series CDT and DAC - christ it's fragile!!!

[Butuz]

Wow great thread.

Butuz

[reddish75]

The heatsinks are there just to see if it fires up, they are a replacement item someone's put in as it looks like (as I have found) good replacements for these transistors are the wrong orentation I.e the back of the transistors face the wrong way. And it's getting to be a twat to find replacement sinks

[earlofsodbury]

The heatsinks are there just to see if it fires up, they are a replacement item someone's put in as it looks like (as I have found) good replacements for these transistors are the wrong orentation I.e the back of the transistors face the wrong way. And it's getting to be a twat to find replacement sinks

Ah, transistors - I'd think about putting them on flyleads and bolting them to the main heatsink - the scorching on that PCB is pretty severe!

[auralflea]

Goodness gracious me! Nice work there so far my man. Looks like this is going to keep you busy until Christmas (Sorry about that!)



The new, shiny parts of that board look pretty though (depths of my technical knowledge there)

[Howlindawg]

Will watch this one with interest...

[reddish75]

Now the kids are back at school work can commence again, rebuilt the first poweramp board this morning, same problems as the powersupply board, nearly everything overheated and heat damaged, mostly new resistors have been installed as the originals were falling apart, a recap, new matched input pair transistors and new zeners and adjustment pots.

Pic's to enjoy.

Notice the heatmarks on the board,


Cleaned


Ready for soldering,


Completed (apart from two out of stock resistors)