Featured Post

Beolover SyncDrive: DC Platter Motor Replacement for Beogram 4002 and 4004 (Type 551x and 552x)

Late Beogram 4002 and the 4004 (Types 551x and 552x), which have DC platter motors instead of the earlier synchronous AC motors usually suff...

Thursday, July 19, 2012

Beomaster Volume Encoder Repair

I finally got around to looking into the not-working volume wheel (encoder). I put a strong LED flashlight on it, and it worked. This told me that the IR emitter in the encoder pickup must have died. A voltage measurement across the diode confirmed this suspicion. The entire 5V showed on the meter, indicating that no current flows through the limiter resistor.
I replaced the emitter with a "OPTEK TECHNOLOGY - OP240A - IR EMITTER 890NM 0.76MM SIDE LOOKING" from Newark (08F2957). The device has exactly the same package as the original defective unit and pops right in. It has a wavelength of 890 nm and a 1.8V voltage drop. The encoder works now like new.

No comments:

Post a Comment

Comments and suggestions are welcome!