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Free but stuffed! Naim Nac32/160/SNAPS

S

SPH

pfm Member
Hi guys.
I was installing a bathroom for a customer recently and we got talking about hi fi gear. He had been playing music while we worked on a Naim Unitilite and I'd commented on how good the system sounded. Long story short towards the end of the job he mentioned he had an old Naim system that wasn't working and I asked what he was doing with it. Well, he gave it to me.
So I now have a nac32, nap 160 and a snaps. None of it works :p
The bolt down nap 160 has some pretty grungy corrosion going on, especially around the power caps. The snaps looks fine and powered up but then promptly let the smoke out of one of the tant caps. I left it alone at that point.

I've done a lot of reading here and elsewhere and I'd like to have a go at getting the system up and running again. Would there be anyone willing to give directions on a project like this? I'll take photos and document the whole thing as I go.

Interested to hear opinions and advice either way.

Cheers

Sam
 
Do you realise how lucky you are? I mean do you really, really realise? Congratulations! From what little I know it should be easier to get up and running than installing a bathroom, and you'll have what is considered one of the great, classic, HiFi systems of all time.
 
SPH said:
Hi guys.
I was installing a bathroom for a customer recently and we got talking about hi fi gear. He had been playing music while we worked on a Naim Unitilite and I'd commented on how good the system sounded. Long story short towards the end of the job he mentioned he had an old Naim system that wasn't working and I asked what he was doing with it. Well, he gave it to me.
So I now have a nac32, nap 160 and a snaps. None of it works :p
The bolt down nap 160 has some pretty grungy corrosion going on, especially around the power caps. The snaps looks fine and powered up but then promptly let the smoke out of one of the tant caps. I left it alone at that point.

I've done a lot of reading here and elsewhere and I'd like to have a go at getting the system up and running again. Would there be anyone willing to give directions on a project like this? I'll take photos and document the whole thing as I go.

Interested to hear opinions and advice either way.

Cheers

Sam
Click to expand...

Welcome to our world.Enjoy the ride.
 
Thanks guys, yes I realised after reading a bit that it's a very well regarded system. I'm in Australia, Tasmania specifically. Pretty out of the way.
Oh, the gear came with all the cables, original boxes, a pair of Linn phono cards and a pair of MM cards.
 
First question is: do you want it to sound like it did when it was new, or do you wish to modify it so it sounds nothing like it did when Naim designed it?
 
PS. The first thing to do it to get it sounding like it did when it was new. You can then make gradual modifications to see if you think they are better or not. Please don't go in with all guns blazing. The process of modification should be a slow and considered one ...
 
Er no - the first question is "do you actually know anything about electronics?"

If not you don't want to be fiddling about with the power amp and it's best left in the hands of your local repair place - who will be able to fix it if they're any good.

The 32/SNAPS can probably be brought back to life by a complete novice with a little guidance, but the SNAPS does have lethal voltages exposed at the mains end so you need a bit of sense, but it isn't that complex.
 
Good point Colas. I remember watching a horror film, where a lady was taking a bath, and the protagonist threw a live Naim amp into the water. It's not a way I'd choose to do a murder though; I don't have a long enough extension lead.

But yes, your point needs to be considered.
 
Pictures would give us a starter, if you can recgonise a tant cap you can most likely fix a Naim.
 
Thanks for the info guys. First point of order should be know how. I'm a novice with electronics but not completely in the dark. I build cnc machines for a hobie. I know enough to be careful with mains power and big caps.
I'd be more than happy to get it working at all to start with. Once I know that every component isn't wrecked I'll start worrying about the sound.
I really can't afford to send it back to Naim. I know that's an option but ts just not viable.
I've already had a repair guy look at it, he gave me the same answer that I've had from lots of repair guys off the years. "Yeah, nah, not worth it". He told me he'd inspected all three when clearly he hadn't. $70 later I'm at home checking it out myself with a multimeter.
 
You lucky, lucky, lucky, lucky, lucky, lucky bastard :D

Seriously though, start as far upstream as you can and work forward with the premise that anything that acts as a source for signal or power should be in a known good state before being plugged into into something that consumes the signal and/or power.

So I'd approach it by first fixing the Snaps, then the preamp, and finally the power amp. This way you also go from (hopefully) easiest to most tricky.

Before doing anything, take a lot of photos of where all the wires are connected so you've got something to refer to later when reconstructing it. You'll thank yourself later!

I suggest taking the source -> sink approach to fixing each item: so for the Snaps, try:


Safety first!
Even after switching off the Snaps, the smoothing cap will maintain a large store of charge @ 38V DC. You will need to discharge this for safety before moving on. I've done this in the past by connecting my voltmeter to the cap to monitor the voltage, then connecting a 5W 1k resistor across the cap's terminals. Wait for the voltage to drop to less than a volt and you'll be good to proceed. Don't touch the resistor with your fingers, it'll get hot.

The slow methodical way
* Isolate the transformer (disconnect the secondary winding from the rectifier) and check the AC voltage of the secondary wires. It's a center tapped configuration.
* If the voltages look sane, connect the transformer to the rectifiers but keep the rectifiers disconnected from the smoothing cap. Check DC output from the rectifiers and, if sane, keep going.
* Next connect the rectifiers to the smoothing cap, but keep the cap disconnected from the regulator inputs. Check DC voltage on the cap. All good?

Once you've got to the point of all being good with transformer, rectification and smoothing, focus can be turned to the regulators. You mentioned that they released the magic smoke. To be safe, I'd replace all the tants. It's a pretty cheap job. I suspect you'll find they're all 10uF/35V parts, but double check. Something like this should be fine: http://www.x-on.com.au/DetailsPage.aspx?MFRN=TANT10UF/35V/5MM&MFR=NETECH&ID=K/q6zEJ/5UyAaPe/egsVVA==

Buy spare tants! Naim use a lot of 10uF/35V tants and there's a chance that you might blow some up. Fun times.

If you have a bench PSU it would be best to use that when debugging the voltage regulators. If not, be careful to discharge the smoothing cap after each time you switch off the Snaps. If you directly short the cap's terminals when it's got a charge in it you'll get a quite a bang and some sparks. Trust me, I know! I left burn marks on a screwdriver shaft after doing so...

The quick n dirty way
Just replace the tants (discharge the smoothing cap first!) and try powering up the snaps again. You might get lucky and see 24V DC at the output. If not, try the slow methodical way!

Hopefully it's going to be as easy as replacing the tants to fix the Snaps. Once you've got a stable 24V DC output from it, you'll be good to move on!
 
Photos of everything (internals/externals) is a help, large and in focus please. Cover different angles and make sure its well lit. Group them into the seperate parts (SNAPS, NAC and NAP). We can then reference bits of the picture to help/guide you.
Make lots of posts here, explain what you are doing/findings etc.. We are (generally) a friendly helpful bunch, and will hold your hand through the process.

:)

Welcome aboard, its a fun ride!!!
 
I started my electronics with a Quad 303 and 405 that my father had given up on. He thought mains hum was the power supply. Nope, not with those amplifiers it wasn't.

What I was able to do was learn from the experience of others and various forums. This place can be among the best for good advice.

The expensive bits to post to places are the cases and the transformers. Most units depend on bits that can be sent away and repaired, particularly the power amplifier boards. The snaps is easy, the preamp has a mains board that is simple to understand. the power amps have a simple power supply and amplifier boards that can become self destructive when failing.

There are some good people on here who can spot problems with only a picture. (Not me I'm an electrical bandit!)

Good luck, you should enjoy yourself.
 
Where do you live? Maybe someone can come to have a look
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I'm in Australia, Tasmania specifically. Pretty out of the way.
Click to expand...

Sometimes you just have to laugh... :D

... but what a fantastic situation & challenge.

If you need an expert hand, I'd try a vintage audio, or even vintage TV & radio, repair shop - looks like there might be one in Hobart. They might not know anything about Naim gear, but they can always look at this thread for specific and expert advice !

I found a place here in NL for my JVC vintage amps and the guy has a local network of electronics experts and is both very reasonably priced, keen to help & seems very knowledgeable (I am not, so it's just my impression).

Good luck with your rebuild !
 
And bear in mind that Naim power amps use a classic, simple circuit. It is essentially the classic 1960s RCA circuit, IIRC. Any competent (rpt. COMPETENT, beware of bodgers) electronics technician should identify it as such at first glance, and know what's what.
 
^^ You'd think so, but I've had to put a number of these right after the local expert had a go at it.

But congrats, there's nothing here that isn't fixable. Is it a bolt up or sleeved system?
 
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