SGC SG-2000 Relay Repair for Deaf Receiver

Описание: In this video, the LPF relays on an SGC SG-2000 are replaced. This cures the deaf receiver issue and improves output power. Along the way, we'll discuss some of the design weaknesses of passing the receiver through the transmitter LPF, as well as the thermal design of the PA and the rather brutal cutting of most bottom solder joints. At the end, we perform a sweep of the Low Pass Filters on the Marconi 2947, and then perform a sensitivity test for the SSB receiver.

Schematics: https://web.archive.org/web/201801180...


Table of Contents:
0:00 Intro
0:50 Disconnecting the wires and screws
4:15 Board Removal
5:50 Where is the heatsink?
7:00 Interesting observations
8:18 Heat transfer discussion
15:40 Start unsoldering the relays
16:39 Comparing the new and old relay
17:40 Footprint verification
18:44 All relays out and cleaned board
19:15 Soldering in a relay
19:49 All cleaned and all relays in
20:29 Installing the board back into the chassis
22:23 Power On
22:54 Test #1: Verify LPF using Analyzer with Tracking Generator
26:19 Receiver Design Weakeness
28:21 Test #2: Sensitivity Test
31:31 Sebnsitivity Test Results for all bands
31:49 Harmonic Test Results