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Recapping a Hi-cap - sanity check

Dr.Exotica

Dr.Exotica

Yma Sumac is a goddess
The other day I contacted NANA to ask how much it was to service an old CB Hi-cap. They came back to me with the astronomical figure of $350 - $500 - depending upon whether or not the regulators needed replacement.

My understanding is that servicing one of these entails replacing the two large reservoir caps ($120 in parts), plus the tants ($1 in parts). I would be shocked if an LM317 needed replacing (easy to check under load with a multimeter once the caps are changed).

Am I missing something here? The figure quoted by NANA seems way out of line for the amount of effort and parts required.
 
You are not missing a thing. And even if the LM317 needs replacing that only costs a buck or so. And the caps shouldn't cost that much either.
 
Thanks for the confirmation Neil.

On a related note - I am always amazed by some of the statements/beliefs held in the Naim Forum regarding the magical nature of the gear. Case in point - only the high priests could possibly service a simple piece of equipment that involves 15 minutes of desoldering and resoldering...
 
Thats what going via the official route cost , remember you are paying for the shop and its staff etc , thats how it is , do it your self , its so easy.
 
neiljadman said:
You are not missing a thing. And even if the LM317 needs replacing that only costs a buck or so. And the caps shouldn't cost that much either.
Click to expand...

Except it is not a standard 317.......but you would be very unlucky to have one that is dead, as they are very under-stressed in a Hicap.

Only really need to worry about the capacitors, and if a very old Hicap, fit a locking DIN socket.
 
I do believe that Naim test and select. Many moons ago I toured the factory and was shown shelves of rejected LM317's, with the worse ones presiumably tossed or used for the less critical PSU's.
 
During a visit to Salisbury in 1983, the late JV took particular care to point out the box of 317s - prominently displayed at shoulder level and marked 'REJECT'. Do you know, business rates being what they are, you would have thought they'd been thrown away long before now.
 
I dont think they would ever make it to the bin for sure. Maybe rejected from use in a Supercap / XPS that kind of thing.

We build data acquisition boards where I work and we have to do screening on some of the essential components. There's probably some benefit in screening and matching certain audio components, for example transisitors in precision small signal circuits, eg Phono Stage.

But sent to the bin, I doubt it ...
 
Reminds me of:

"He's an halibut ... I didn't like the others, they were all a bit too flat"

Fish License - Python!

As for the sanity check:

"I am not a looney! Why should I be tied with the epithet looney merely because I have a pet halibut?"
 
The best go into the supercaps and hicaps. the less good go into the NAPSC. They do seem to bin some regulators because a couple of years ago Paul Stephenson put a post on their forum offering the rejects for sale, rather than them being thrown out.

I saw the test rig when I was last in the factory, but not sure what the device was measuring...take your pick from noise, linearity etc.
 
Perhaps I have been a little bit hasty with my "don't you believe it" comment. I was speaking with a friend on the weekend, the company which he works for makes high quality regulating power supplies for industry, he tells me that they buy on quality and performance and once they have a supplier and product that meets the spec they stay with it. But before they do, they test, at length.
I am sure that a company of NAIM's standing would do the same. As for the most of the rest, my original comment would probably stand.
Regards
Errol.
 
Apart from some very individual selection for gain parameters, with only few exceptions, I tend to have faith in the test procedures of the company who made the things in the first place. If a bulk-foil resistor is marked as having 0.01% tolerance, it's time consuming and nonsensical to me to have to verify that, not to mention the expense of the test gear required.

No amount of 'hand balling' is going to improve that figure once it has left the factory.

The industry standard 317 circuit is so noisy that no amount of 'fondling' of devices will instill any measure of 'magic' into what is effectively a general purpose, industrial power supply.

By simply adding a gyrator to the equation, you're cooking on gas.!
 
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