I posted this as a new thread, but thought it would be helpful here too.
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.
