Dilshan R Jayakody’s Web Log

I recently had the opportunity to work on another Pioneer PL-250 turntable. The previous owner was having an issue with the platter moving back and forth without continuously rotating, which can be a frustrating problem to deal with.  After a quick inspection, I found that the issue was caused by some faulty electrolytic capacitors (3 × 470µF) near PA2005 and a bad bridge rectifier. These components were preventing the platter from spinning smoothly in the right direction. Fortunately, I had the necessary replacement parts on hand, so I quickly swapped out the bad components. Once the new capacitors and rectifier were in place, I gave the turntable a full service to ensure that everything was working as it should. After completing the repairs and maintenance, I tested the turntable and was pleased to see that it was now spinning smoothly and continuously in the correct direction.

Philips 852 is a tuner, turntable with an amplifier which is manufactured by Philips around 1975 - 1977. The tuner stage of this receiver consists of 4 bands such as LW, MW, SW, and FM. This unit also comes with dual-speed (33⅓, 45 RPM) belt driven turntable. The power amplifier of this unit is delivering 2 × 9W audio output power with a pair of 4Ω speakers. The 852 which we got had problems in power amplifier and turntable mechanism. After tracing the problems in power amplifier, we figure out that both BD262 transistors had short circuits between emitter and collector terminals. Because BD262 is no longer available in the market we replace both NPN and PNP transistor pairs of this amplifier with BD678 and BD679. Philips 852 player after cleanup and restoration. The turntable mechanism of our 852 had many problems due to several missing/damaged parts. Most of the parts are damaged due to corrosion and we fabricate most of them using 3D printer and lathe. The missing anti-ska...

Pioneer PL-250 is direct drive auto-return turntable with the s-shaped tonearm. This turntable is manufactured by Pioneer in around 1979 - 1982. The PL-250 which we got had many electronic and mechanical issues. The main electronic problem in this unit is it's varying speed. The speed controller of this turntable is based on PA2004 and PA2005 ICs. After checking each an every electronic component in speed controller PCB, we figure out that the problem is in the " Pitch Control " potentiometer (VR1) of this unit. After replacing VR1 with 5K (log) potentiometer, the speed problem got resolved and the motor starts to spin with correct speed(s). Servo motor and speed control assembly of Pioneer PL-250 turntable. The turntable which we got comes with original Pioneer cartridge with "broken" stylus. We test several cartridges with this player including cheap US $ 3.00 cartridges (which are available on eBay), Audio Technica AT-91 and Audio Technica AT-95E ...