Sunday, April 16, 2017

Restoration of Philips 852 - 22RH852 turntable / tuner

Philips 852 is tuner, turntable with amplifier which is manufactured by Philips around 1975 - 1977. The tuner stage of this receiver consist with 4 bands such as LW, MW, SW and FM. This unit also comes with dual speed (33⅓, 45 RPM) belt driven turn table. The power amplifier of this unit is delivering 2 × 9W audio output power with 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 antiskate-spring is replaced with modified spring which we got from another broken record player.

After the above fixes Philips 852 start to work again. With large 3 way speaker system this unit produces very good audio quality. The only drawback which we notice with this receiver is it's less sensitive tuner. Compare with most of the receivers SW and FM reception of this receiver is quiet poor, but this can be improve by using good external antennas with this unit.