Mark 1 - the original “Shack-in-a-box”

• HF 100W
• 6m 100W
• 2m 10W

• From the Silent Key equipment of Peter GM0CXQ

• In poor condition cosmetically, internally and externally
• Intermittent RX performance on several bands, most severely 6m, due to LPF switching relays
• No Power cable
  • ordered via eBay 24/5/23
• No microphone
  • ordered via eBay 25/5/23
• Not “MARS” modified to give access to 60m

• Sensitivity ok on all HF bands
• 6m shows intermittent “deafness” after changing bands - LPF relays?
• Initially some higher HF bands also showed slow decrease in sensitivity after a few minutes. After transmitting a few times on each band this tendency stopped - have the LPF relay contacts “wiped” themselves clean by carrying more significant signal current on TX?
  • 6m still suffers random RF signal loss on RX
• TX power ok on all HF bands, and 6m, with 100W FM carrier at setting “H”
• All controls work correctly
• Fitted FL-233 “Narrow SSB” filter option appears to work (TBC)

• To cure signal loss on RF I removed the LPF board and was able to pop the clear plastic tops from the relays used on either side of the 6m LPF section.
• Contacts in RL2 and RL3 cleaned with Contact Cleaner spray, and wiped with paper soaked in cleaner to remove any dirt/contamination build-up.

• Caps replaced on relays and LPF board replaced.
• Receive sensitivity now good and does not vary with time, or following band changing.
• The relays used on the other HF bands are of a different (more easily sourced) type and can't be opened in this manner. Fortunately they all seem to be healthy at the moment.

• To allow use on the 60m band I carried out the simple modification to remove “D59” from the Main PCB, which removes the “TX only in Ham Bands” restriction.
• Radio now transmits across the whole HF band, including 60m

• https://groups.io/g/IC706
• http://www.hampedia.net/icom/ic-706-enables-out-of-band-transmit.php