19-07-1998 add a comment TR851E & TR751E with 9600 Hello, Carl! I have read one of your messages - you have asked for modifications of TR851. I am also using TR851E (European Version) and TR751E with my 9600 BD- Modem (G3RUH) with the following modifications: When you remove the bottom panel, you can see immediately all you need to do the modifications: Varicap Diode D21 IF-Filter CF1 Discriminator IC2 View from bottom side: Power in Antenna ---------------------------------------------------------------------- I I . . . . . . I I I Quartz I I 1 2 I I -D21- I I I---I ..I I I...I CF1 I I I---I I I I I 1 I I --------------------- I I I IC 2 TA7761P I I I --------------------- I I 9 I I I ---------------------------------------------------------------------- Microphone Tuning Knob Volume Contr. IC 2 Discriminator PIN 9 of IC 2 ------->- Capacitor (100nF) ------> -RX-Audio G3RUH-Modem D21 Varicap-Diode Pin 2 (has no ring!!) --------> TX-Audio G3RUH-Modem IF-Filter (G3RUH recommands changing) Replace CF1 ( 55 F ) with CFM 455 D I thougt that the replacement of CF1 was too difficult for me. So I have asked a good friend to remove the PCB and to replace the filter...no problem, he said, and for him it was really not a problem. The other modifications I have done by myself . I have done the same modification to TR751 without changing the IF-Filter, because I only need TR 751 for uplink. The components on the PC Board are close one to another, but I think that other TX/RX are more problematicly to modify. This modification is read 1018 times. top of page add a comment