Friday, January 22, 2010

Tecsun PL-200 (Eton E100) repair: replacing volume control resistor

After about four years my Tecsun PL-200 got a problem. Volume control produces noises and cracks, and volume becomes unstable.
The volume control resistor needs to be replaced.
After disassembling receiver I found 7-pin resistor on the analogue PCB, which needs to be replaced

























After unsoldering it from PCB I found only one label on it - "B203"
























By googling for "B203 resistor" I found spare with p/n R1001G22B1 from Chinese supplier named Song Huei. This is dual-section variable resistor. In PL-200 it has resistance about 20 kOhms of each section (my measures shows 17.9 kOhms on one and 18.2 kOhms on another section). But here in Moscow only two nearest values available - 2x10 and 2x50 kOhms.
I observed PCB and found that both sections of resistor are shortened in parallel.






























As you can see pin pairs 1-2 and 3-4 are shortened. So, this dual-section resistor in fact works as single-section 10kOhm resistor and I can use 2x10 kOhm spare after cutting off one section. So I got spare (noticed above) for 15RUR (about 1/2 USD). The disadvatage is that spare has smaller and thinner knob and knob unchangeable




































To exact replace I need to cut off two pins of one section
























And solder spare resistor back to the PCB
























Volume control after such repair becomes not so convenient as before due to smaller knob, but it works perfectly. And now some receiver shots after repair and assembly














































2 comments:

  1. Anonymous17/4/10 06:34

    Maybe you can glue something onto the knob to make it bigger. Maybe a quarter ($0,25), I guess a beer bottle cap is to big. ;-)

    My E100 (same radio) stops working after pressing buttons several times. When it does this it won't even turn off.

    Paul
    Canada

    ReplyDelete
  2. Paul. this looks like broken soldering or PCB of processor board

    ReplyDelete