Thursday, March 23, 2017

Luxman PD-121 Plattenspieler Upgrades



Luxman PD-121 Plattenspieler
Today were highlighting some upgrades performed to the  extremely popular Luxman PD-121 Turntable. The PD-121 is a two speed, DC direct-drive with a motor suspension, heavy mass platter (2.4Kg), touting a modifiable Bayonet mount which was commonly paired with a SME 3009 or better.  Below is the OEM arm supplied mounted. 




One of the common failures on these or the black-light strobe due to a failing 4.7MFD capacitor. Instead of replacing with another cathode strobe we elected to perform the LED modification. Using the 23Vac source we are able to tie in a series of diode emitters and mount appropriately for a clean, long last illumination of the speed tracking. 


The black-light drive circuit can be removed, as I did, as the buss is no longer needed nor the circuit behind the 33/45rpm adjustable speed tune controls. At this time  the two phenolic rotary pots were cleaned and lubricated with Caig Lab products. 





The Power supply PCB had the electrolytic replaced as well with low impedance, high temp (105C) Nichicon PW capacitors with an increase in operating voltages, new UF (Ultra-Fast) Diodes installed and new thermal compound for the voltage regulator. 13.5Vdc rails were confirmed.


 Regulated 13.5V supply Vpk





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