Technics SP-10MK3 Turntable and JP Jones Replacement Chip for MN6042


I've owned my Technics SP-10MK3 for several years now. During that time, 3 or 4 of the vintage MN6042 chips have failed in the control unit. My chips have failed altogether, rendering the table unusable, or partially failed, rendering the pitch control unusable, but the table otherwise works. 'Works" may be unfair, since its wow and flutter figures (using the Analog Productions test record and iPhone Feickert app) worsen significantly, but are still good enough to embarrass many turntables.


This chip drives the quartz synthesizer pitch control and LED display. As any owner of the MK3 will tell you, this is the Achilles heel of the turntable. Many owners have invested considerable sums of money in these magnificent direct drive tables, and before now, the fear of losing the table altogether due to a chip failure loomed large. The table will not function properly without it and the chip has not been available for some time. As a result, many have squirreled away donor Technics tables which use the same chip, like the MK2 versions of the SL-1300, 1400, and 1500.


JP Jones of Fidelis Analog, who has written in the Audiogon forums, spent the time to design a replacement for the MN6042. The most recent failure of my vintage chip was some months ago, such that the table played, but without pitch control and higher wow and flutter. Rather than using a backup MN6042 chip, I decided to try the Fidelis Analog replacement. JP says that he has never seen a vintage MN6042 operate correctly, even when they appear to be, and he's measured nearly a dozen now.


JP also adjusted all other parameters in the control unit per the MK3 service manual AND looking for adjustment clues elsewhere, as well as utilizing his own processes he’s developed. According to JP, the service manual is wrong or incomplete in some cases. What I notice is that the turntable responds better at startup; i.e., it doesn't start with that incredible torque, overshoots, and then corrects.


By the way, JP is fantastic to work with - a consummate professional who does what he says he will do.


For quick background information, my MK3 has the excellent Krebs modification, which I've written about on these forums before, and the excellent Porter plinth. I alternate different cartridges in the SME V-12 and 12" Graham Phantom 3 Supreme tonearms.


I received the control unit back. After spending time listening to many records, it's clear that my MK3 has been sick for a very long time. It now sounds fantastic. I've never heard this table sound so good. It has analog tape smoothness. (I have several reel to reel machines and master tape dubs, so this is not a throw away comment). I've always liked that about the MK3. When it has a healthy vintage chip in it, it has this smoothness. Even more so now.


Now what is blowing me away is this incredible, unassailable energy and drive. This table is unfazed by anything. I can hear and follow complex rhythmic structures like never before. And it has the huge soundstage and incredible detail to go with it. Massive, perfect-pitch bass. I'm loving it!

This chip breathes new life into the Technics SP-10MK3.
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Now I've heard it all.
Sweet
Furthermore, JP is a godsend to all of us (not just Technics owners) who admire the finest direct-drive turntables of yesteryear (sorry, Lone Ranger fans). I have a Victor TT101 that I bought cheaply, because it was "broken".  For 3 years thereafter, I searched for someone who could fix it. Two really respectable guys gave it a go, but without success.  I was beginning to think of the TT101 as a doorstop, when I came upon JP's MN6042 thread on DIYAudio.  I contacted JP, and he agreed to take a look at the TT101.  What he eventually found was a tiny crack in one of the PCBs that was intermittently interrupting the circuit.  The crack was nearly totally covered with solder, so even harder to detect by eye.  Once he identified this flaw, by logically tracing the circuit to see where the failure was likely to be occurring, it was no problem to fix.  This all came to a head about a year ago, and my TT101 has been operating flawlessly ever since I got it back from JP.  Kudos. It's a great turntable.
I also own a Mk3, also with Krebs mods.  I bought the MN6042 PCB from JP but have not had him install it yet, because my own Mk3 was NOS when I got it, and the OEM MN6042 has never given me any trouble. But I know the Mk3 will work even better with JP's substitute circuit installed. Thanks for your report, K.
This is, of course, brilliant news.
In the past there has always been that little bit of worry eating away at the enjoyment of owning a MK3. "What happens if/when the chip fails?"

No more. JP has saved us from this angst and improved on the TT's performance. A perfect solution.

Cheers.  

@roxy54 I don't understand your post or supposed astonishment. It seems eminently reasonable to me that replacing a non or poorly functioning chip with a newer more robust version would improve sound quality. Not to mention reliability and most importantly future longevity.
jond,
It was just tongue in cheek. I had no idea about the existence of this chip at all, and was amazed that there were smart analog geeks who not only knew about it, but could invent a new one. Good work guys!
roxy54
 amazed that there were smart analog geeks who not only knew about it, but could invent a new one

They are indeed "few and far between".
Agreed it is very impressive indeed!
I went onto Fidelis Analog's website fully expecting to see an outrageous price for the Technics MN6042 upgrade chip and to my surprise, I learned that it was ONLY $200.  Nicely done!
Well done, JP! That is awesome work on your part. Cheers,
Spencer
Thanks, guys!  Glad to help.