Show Off Your Linear-Tracking Turntables

[Gepetto]

My beautiful PL-L1000 stopped tracking. It was intermittant at first, but eventually even the rotary position failed to move the arm. I hoped it wasn't the CdS cell in the arm carriage, but realized that it had nothing to do with the rotary movement control. I tore it apart and dismounted the circuit board, got all the cap values from the board- not the parts list or schematic- and replaced them. I never thought there was such a thing as a non-polarized electrolytic- I always thought that electrolytics were polarized by nature!

Works perfectly now, except one thing- misses the edge of the record by about 2mm. The wiring harness isn't long enough to connect the front panel controls with the top cover disconnected to adjust the pots. I can live with that, just can't depent on the automatic start when I press the button.View attachment 77866

Would have been nice if they labeled what the 8 pots on the board do. They had a silk screen after all.

 

[George S.]

I second that motion...
I finally found a decent Transistor Tester, a Sencore TF-151A. I had to change out the electrolytic capacitors. There are better transistor testers out there (I think the TF-166 has more bells and whistles), but this one does test Gain in a High and Low range (Power and Signal transistors). Most of my measurements are for comparison and matching, so the absolute values are not that important to me. I have discovered several "bad" transistors that might have passed the diode junction tests or were not showing a direct short to the casing.
So much better than swapping digital VOM leads.

The fun part is measuring some original Phase Linear XPL909 NPN transistors. They typically measure 10-30 Gain, compared to the ONSEMI MJ21196G, which always measure a very consistent 50 +/- 5 Gain. But I occasionally find a XPL909 with a gain of 9 or 4, or 2!
Again, these are the numbers from my Sencore, not absolute values.

Second the Sencore 151A. Very nice unit. I also recapped mine. Stay away from the 151, a point to point wiring cluster ****. The A model is much improved with a actual circuit board.

 

[Vintage 700b]

Second the Sencore 151A. Very nice unit. I also recapped mine. Stay away from the 151, a point to point wiring cluster ****. The A model is much improved with a actual circuit board.

I have a TF-151A and love it. Also recapped a while ago, and it is super dependable.

 

[grapplesaw]

Hi Mark

there are a few issues with getting the the linear tracker tuning. First the bearing on the back of the carrage need lubrication of right type
Also tuning the pots is not easy as they glued them at the factory

pm me and we can talk about what’s needed

 

[MarkWComer]

Hi Mark

there are a few issues with getting the the linear tracker tuning. First the bearing on the back of the carrage need lubrication of right type
Also tuning the pots is not easy as they glued them at the factory

pm me and we can talk about what’s needed

Yup! Tiny little ball bearing races! I have watch oil and I should have taken care of that. I need to disassemble again (WHAT A BITCH!) because I didn’t replace the PS caps.

THEY GLUED THEM?​

 

[grapplesaw]

Well you can pull the rubber cap off it while it’s together. You need light food safe silicon grease or oring grease not oil. I’ll see what the viscosity is for you
once that is lubed right it may work properly. If no calibrating mean full disassembly
I’ve build extension cables and makes this possible to operate and adjust

 

[MarkWComer]

Well you can pull the rubber cap off it while it’s together. You need light food safe silicon grease or oring grease not oil. I’ll see what the viscosity is for you
once that is lubed right it may work properly. If no calibrating mean full disassembly
I’ve build extension cables and makes this possible to operate and adjust

I have a couple different viscosities of silicon grease that I bought to work on my Dual turntable, they're not light, used in the cue lever. That cap for the bearing is below the carriage, hard to reach to pry it off, but as I said, I still need to swap the PS caps, so removal of the top cover will need to be done anyway (wunna deez daze). I'm not overly worried about it missing the edge of the record, although it would be nice to hit "start" and walk away.

There are three bearing races on that carriage, when it's opened I'll hit all of them. When I first got this the screw on the back bearing was out and the belt for the arm elevator was broken and in the bottom. The only real maintenance I do is wipe the rails off periodically for smooth operation.

Nice idea for the extension cables! If I was going to do a calibration more than one time, I'd make a set.

Still can't believe they glued an adjustment pot...

 

[grapplesaw]

Sounds good Mark
Just grease the one back bearing
Light oil the front ones