SX1980 Power supply board ...... OH NOOOOOOOO!!!!

Hey guys, here we go, I have a SX1980 on the bench, the owner said "it was going and then it went ffffffffitzzzz....He said, it should be an easy fix because it was previously working. I said, nothing on an SX1980 is an easy fix!!

I picked it up and before anything else went straight to the PSU board, and rightly so.

I have done some research here and EW's remote mounting of the transistors which looks like a great solution...So I have studied that thread.

However, this board is absolutely trashed. Its had multiple repairs, bad repairs, the ones where its like "I cant be bothered working on this lets get it out the door".

So I never bothered powering it up obviously, there are leaking caps, the board is toasted, damaged tracks, some odd diode added somewhere for something and such.
The Fuses FU1 and FU2 were blown surprise surprise

Missing, is Q207, Q209, Q213, completely gone....I was wondering why and how this was powering up with them missing!! The owner said it was going, but used to emit serious amounts of heat...

I'm just after a bit of guidance through this, I am going to work hard to bring this back to operation.

I thank you all for the great information here in this forum, very very valuable information.

Here are some pictures to see what I have to work with.

.

 

Message member txturbo regarding a possible solution.

 

yikes! You got your hands full with this guy......

 

Wow, you are on the long end of a parts pipeline.

I hate to say it, but I've seen and overcome worse. Deliberate, methodical work will win.

 

Yeah, I've dealt with worse than this, one particular McIntosh comes to mind.
I have done a bit of searching and found some great info here, but as yet, a definitive substitute list has not shown yet, I want use parts that are tried and tested by you good folk...not really keen on going out on a tangent...

 

well, Mouser DOES allow changing the base country to New Zealand.

See how much of a premium they charge for shipping, and try to get the order in one fell swoop.

 

That PSU board is actually not bad at all. Mouser is free shipping over AU$50- it'd be the similar for you over in NZ.

I'll see if I can dig up my Mouser BOM for the PSU board.

 

Don't pull the trigger on any orders until we run through the order. I've done quite a few SX-1980's, probably second only to EchoWars.

Or you could get the TxTurbo board on eBay - worth every penny, just a lot of them.

I have a list of all the 1980 parts I do on a rebuild, over 200 items and WAS at $200 or so last time I ordered (IIRC).
That did NOT include new main caps or new power amp outputs.

 

Kevzep,
X-On Australia is the local distributor for Mouser listed parts.
That's where I've been getting all my bits from.
I'm in Sydney and you're just over the ditch from me.
You can send them an excel spread sheet BOM with the mouser part numbers and they will take care of the rest.
Local shipping costs would be more easier on the hip pocket than ordering from the U.S.
http://www.x-on.com.au/

 

Thanks Mark appreciate you chiming in, I'm up for rebuilding that particular AWR154 its really not that bad compared to some boards I have seen.
Totally recoverable, but I will remote mount on the main Heatsinks, the +/-80V regs they seem to be the ones which cause most of the issues.
I'll upgrade the heatsinks on the others.

I will post a list to make sure I am on target with the right parts, you and EW are the gurus with all the experience on these units, I will take all your advice, just as I am sure if you ever worked on a Crown Macrotech 5002VZ, I could advise....

I sent txtubo a message, so I will look at that, but I suspect its going to be more than the customer wants to spend....good to have options though!!

I am warming my customer up to the fact that this is not a case of a quick fix and return everything to factory!!

I told him once we have it operational we'll find a whole new pile of things that need to be addressed!!

 

Our company has an account at Element 14, so I always try and get as much as I can from them, but this sounds like a good option, I am sure I'd be directed to the nearest mouser distributor which is most likely these guys...

 

Ah yes. They Exist here in Sydney at Sth Granville actually.
I was going to mention them, but didn't think you'd heard of them.
If your company has an account then you'd probably enjoy a decent discount.
Excellent !
I'll be watching this thread. Very interesting stuff even though I don't have a 1980. I'd love to some day though...... yeah dream on ......

 

Believe it or not, if you order before 4pm our local time, you can get the order overnight by 10am our time the next day, pretty good service.
Sometimes there's the odd thing they don't have, but in the case of this job, they will have it all I am sure...
I am pretty sure this SX1980 would be one of a very very few in New Zealand, at last I get to hear one!!
I was thinking of getting a 1980 after I sold my Sansui G22000....Now there's one on my bench, but its not mine!!

 

Yes they do, and I even have an account there, are you able to help me with a BOM list? Or should I compile my own and post it here?

 

Probably better wait for Mark to offer his list.
Does the customer want the whole thing refurbished or just get it "FIXED" ?
If I were him, I'd refurbish the entire unit and be done with it for reliability's sake.
No good doing one part only to have another fail some time later.

 

I found a list by mattsd, I can copy and paste that and then post it here and have the gurus view it and point out anything that needs changing, its even down to using the 24V relays and the mod to make that work, has all the semiconductors as well so that's good too...

The customer is a gun shy, and very concerned about originality, I'm going to work on him little by little and eventually end up doing the whole thing.

 

I think Originality is a foregone conclusion when dealing with vintage gear, especially the 80 series receiver amps.
I'm sure most on the panel here would agree.

 

Absolutely, although as far as the AWR154 goes, there are modifications that really have to be done, I'm just reading up on the current source mod, which is essential for reliability in years to come...
I just need to get my customer to be relaxed and trust me that the unit will look the same, but be forever reliable...

 

Good Luck Kev, I'll be little or no use for advice having never seen or worked on one, and in any case you have the very best helping already. I'll drop in every now and again to see how you are getting on.

 

It can be an original doorstop, or a working unit with a lot of modern transistors and caps. The market has determined that WORKING is the breadwinner.

For current source stuff, find the sx-1980 threads by anderslober in the pioneer audio forum, it has GOOD, annotated pictures of what's removed and what's added.You're in some of the threads too, so you should remember a bit.