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Naim Hicap LM317K TO-3 package availability

nobeone

Total Member
I seem to have blown up a LM317K TO-3 in my hicap - can't see what else it could be, not exactly a complex circuit, there is c.40Vdc going in, nowt coming out on one regulator, c.25Vdc on the other ... the resistors are all intact so ...

I know Naim did a selection job on these to filter out the damn noisy from the normal, and if you were lucky the surprisingly quiet from the normal, but let us assume most of us will "get lucky" and not get a noisy regulator, the issue for me is where are these available from now?

I can't see much out there, and what I can find is daft pricing £30 for a single regulator, before delivery, but I suppose that is not unusual for essentially obsolete parts.

Oh, I should say, I am aware I can replace the hicap PCB with 3rd party replacement improved parts, that is great, and I am exploring that option, I am just trying to fix this hicap PCB at this time ...
 
Let me think back to when I did these on the bench.. I reckon only about 1 in 20 were noisy. And by that I mean they exceeded something like 20uV wideband noise under load. Very, very few were dead altogether but they were rare. The unselected ones made it into the NAPSC and NAC52/SC digital supplies, the selected ones made it into Hicaps and Supercaps alike. There was never any special selection for the Supercap, which used to keep coming up on the Naim forum from time to time as a fact.
 
Let me think back to when I did these on the bench.. I reckon only about 1 in 20 were noisy.

Yeah one of the first jobs I did, testing 317s, I would say so something like that, been a long time though, and 1 in 100 very quiet.

So any clues where to source them? Can you help me out Mark? :)
 
Thanks Pete, I'm sure that works too, but I'm looking for a fix that leaves it as close to factory as possible at this time, not least with an eye on resale. Alternatives appreciated though!
 
While I haven't bought 317s from Nikko Electronics, other stuff I have got has been genuine.
 
Thanks for the replies pigletsdad and Neil, much appreciated. Mark has been kind enough to help me with some pulled from hicaps. However it is great to know of the existence of Nikko Electronics and the TI parts. I know there exist a number of suppliers that stockpile obsolete components, some may be not so new, some fake, some genuine NOS. Some of these guys are ultra careful as they operate at high profit to keep e.g. military kit going decades after obsolescence where component change would be unacceptable. Some of these guys are just crooks. Bought tens of old SCSI HDD from one once at big £££ and they were sold as NOS, but from the grinding sound of the bearings on start up and the quantity that were unserviceable ... they were clearly pulled after years of service, cleaned up, wiped, and out in new anti static bags.
 
OT: It was a 1980s design, I worked on it for a decade and more, it is still in the field today AFAIK. A bespoke 68k CPU board with integrated SCSI (that is SCSI original, 1 as it were) controller running an obsolete RTOS with driver in assembler. Changing to a newer drive interface would really be a huge effort, arguably better to redesign it all, but there was no appetite for that, so we kept the clunky old stuff going as best we could. Military came to our rescue again: SCSI flash drives ...
 


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