Hi Larry et al
The QRP++ master reset was successful. Thanks Larry. Good to know that the EPROM was not corrupted.
I managed to extract the Index-1 mixer with the help of a desoldering gun. The pins of the mixer were tight with the holes and it was not easy to get it out from the board. I hope I did not damage the plated through holes. I will have to double check continuity on the solder side and perhaps bridge some connections.
The replacement level 13 double balanced mixer is already on the way. I will use a MCL SBL-1MH+ although the engineer at Synergy Microwaves told me that they were still able to supply the original custom Index-1 mixer or the same one they manufactured for SGC which is their part number SGC313011, just in case somebody else in the group had to replace the RX mixer. Unfortunately, the minimum order of Synergy Microwaves is $100, so it makes no sense to buy the "original" mixer. For all those who are not sure about the Index-1 pinout, I recommend to download the SG-2020 manual and they will realise that the RX schematic is a replica of that of the QRP+ and the drawings are clearer than those in the QRP+ manual.
The summary is as follows. Pin 1: RF IN / PINS 2,5,6,7: GND / PIN 8: LO / PINS 3,4: IF
Keep the group posted on the progress.
72 de Vicen?, EA3ADV
Vicenc Llario, EA3ADV