LINN PCB 018 (Speed-Checker, 300 Hz Turntable Strobe) Questions to the Circuit Diagr.

Follow questions rises up to Linn's speedchecker when looking at the circuit diagram (schematic under the first attached image):

1) What is the reason for the not present of Rx, which determine the idle current through the first transistor of the darlington LED driver ?

2) Which task has the connection at the other end of R2 (here is a not connected solder pin provided) ?

3) Why a jumper at R1 to the popsitive rail (Vdd) ?

4) From where I can get the genuine enclosure (no longer available from Linn since any years) ?

Best thanks for advices in advance.
 

Attachments

  • DSCF4081.jpg
    DSCF4081.jpg
    745.5 KB · Views: 370
  • 40601.gif
    40601.gif
    8 KB · Views: 365
  • Linn CYMRJsQWkAAu0Tj.jpg
    Linn CYMRJsQWkAAu0Tj.jpg
    93.4 KB · Views: 354
  • Linn 611listen.speedcheck.jpg
    Linn 611listen.speedcheck.jpg
    56.8 KB · Views: 339
  • Linn Speedchecker.jpg
    Linn Speedchecker.jpg
    3.7 KB · Views: 334
  • linn+strobe.jpg
    linn+strobe.jpg
    94.8 KB · Views: 1,011
Last edited:
A friend of me is looking for a genuine 300 Hz speed checker für his LP-12. Maybe one of the member know, where it is available in uzsed condition.
Thank you very much.
In the attachment two templates for strobe discs (for print) as PDF.
Both 50 Hz and 300 Hz
 

Attachments