V4.1 AK4951 Companion Board ONLY
Beginning with V4.1, microphone DC Bias is disabled by default. If you
are using a condenser microphone (or otherwise) and need DC bias, apply
solder to JP1 Solder Jumper pads to jump it. SJ1 is near the IC U2 on
the board above R3 and below C20 (C20 is not populated).
There are eight steps involved in V4.x AK4951 Companion Board installation.
1. (If required) Disassemble your Hermes Lite 2 and remove Ferrite Bead FB28 from the bottom of the HL2 board.
2. Plug the Companion Board onto the HL2 board.
3. There are two methods of controlling DC power to the HL2+. You must decide which one you will use and complete the installation accordingly. There is a separate page with details on the 2 methods. A link can be found below.
4. Mount the DB9 Ribbon Cable to the new HL2+ rear end plate. Plug the IDC connector end onto Companion Board J4.
5. If desired, mount Pure Signal pigtail cable bulkhead SMA to new HL2+ rear end plate. Connect pigtail coax as follows. To Header Jumper pins 7-8 connect cable shield and to Header Jumper pins 11-12 connect cable center conductor. See Pure Signal page for a photo of these connections and HL2+ Accessories for a pigtail cable source.
6. If desired, connect an (optional) HL2+ internal speaker with 2-pin Dupont connector harness to Companion Board J5 after making proper mounting accommodations in the HL2 top extrusion half and mounting the speaker.
7. Reassemble your Hermes Lite 2 + transceiver.
8. Update the Gateware (FPGA Firmware) in the Hermes Lite 2. See the Gateware Update link on the homepage.
The
V4.x kit includes new HL2+ end plates for the HL2 40mm case, a DB9
cable for the Hardrock-50 interface, a power switch, a 2-wire harness
for the power switch, a 2-pin header for the harness, a mounting bracket
for the PCB, along with the V4.x AK4951 Companion Board.
Hardware Installation
(If required) Disassemble your Hermes Lite 2. There is a ferrite bead (FB28) that *** MUST BE REMOVED *** from the bottom side of the HL2 board.
If you take a small soldering iron and feed enough solder to it to form a small ball at the tip, just enough to touch each side of FB28 at the same time, the bead will easily lift off of the board with just a touch. Next, begin reassembling the Hermes Lite 2.
Here is a picture of the Hermes Lite 2 ready for the installation of the Companion Board. The heat sink shim is not shown here. Be sure that you reinstall it when reassembling the HL2+.
Note that there are two headers near the front edge of the HL2 board. The front one has 20 pins (DB1) and the other 6 pins (DB12). These are the pins that will mate with the female headers on the Companion Board.
Carefully line up the pins on the two headers on the Companion Board with the HL2 board headers and apply light pressure to completely seat it.
The link above is to instructions for installing the power switch. There are two methods for connecting the power switch. After reviewing both methods, continue to the detailed instructions for your chosen method.
Here is the Hermes Lite 2 + after installation of the V4.x Companion Board and new front end plate. The picture also shows the DB9 connector/cable, power switch/cable/header, and rear end plate in place. Note the 2-pin connector (J5) on the rear of the Companion Board. This connector provides 400 mW of audio for an small internal speaker or a connection to an external amplifier for a larger speaker.
An "L" mounting bracket is supplied to support the AK4951 Companion Board, especially when microphone or headphone jacks are inserted. A M3 clearance hole needs to be drilled in the cabinet side 19.5mm from the front edge of the case extrusion half and 17.25mm from the bottom. The hardware used to secure the bracket and companion board are 2) M3-0.5 x 5mm screws, and one or two sets of M3 flat and lock washers (depending on what screws are used, read on). For the Companion Board side of the bracket, a pan head screw and the washers are used. For the case side, I like to use a flat head M3 x 0.5 screw (so no washers) but a pan head (with washers) is fine too if you do not mind the protrusion of the screw head from side of the case.