G4HUP DFS Issue 2 Errata and Updated Information
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Issue 2 PCB problems

Problem
Location
Affected Circuit
Resolution
Implementation Versions Affected
No Vcc on IC201
short trace missing between +8v via and R201/C208/9
IC201
Link with short wire from via to R201
All implementations - 8v Vcc to MAR-6 in VHF multiplier amplifier chain

Issue 2 PCB Modifications

Purpose
Diagram Ref
Status
Instructions
Implementation Versions Affected
Performance (Spurious outputs) improved by fitting Diplexer in some cases
Sheet 6 - VHF Mixer Circuit
Recommended Modification
Make mods as per diplexer
Any version with a wide spacing between the VHF multiplier frequency and the MF signal
Performance (F6 Filter) improved by modified coupling
Sheet 5 - LF Mixer Circuit
Recommended Modification
Replace C504 and 505 with single equivalent value - place between hot pin of L502 and ground. Use a small C (22 to 47pF) to couple from the top of the L502 into the base of TR501 as shown using the C504 position.
All Iss2 DFS versions

Page created 18 May 2008

Page last updated 18 Mar 2010