HobbyPCB HARDROCK-50 User manual

HARDROCK-
50
Assembly Instructions
Jim Veatch
WA2EUJ
5 December 2017
50
0.5W to 5W Driver Amplifier
Assembly Instructions
– Rev C.
0.5W to 5W Driver Amplifier

TABLE OF CONTENTS
1. INTRODUCTION ..................................................................................................................................................1
2. SPECIFICATIONS ..................................................................................................................................................2
3. ASSEMBLY OVERVIEW ........................................................................................................................................3
4. DRIVER INVENTORY ............................................................................................................................................4
5. DRIVER PCB .........................................................................................................................................................5
6. INTEGRATION .....................................................................................................................................................9
7. SCHEMATIC DIAGRAM ..................................................................................................................................... 12

1
1. INTRODUCTION
Congratulations on your purchase of a Hardrock-50 driver amp. This amplifier mounts inside the
Hardrock-50 amplifier decreasing the drive requirement from the standard 5W input for 50W output to
0.5W input for 50W output.
Construction and installation of the driver amplifier assumes that we are starting with a fully functioning
and tested Hardrock-50 amplifier. If your amplifier does not work please troubleshoot it first, adding the
driver amp is not likely to clear up any issues and is likely to complicate the troubleshooting procedure.
The Driver amp is not compatible with the ATU or the QSK that mounts on the bottom cover which was
used with HR50’s with serial numbers below 1200. The driver is compatible with the mezzanine QSK
board that mounts directly on the main amplifier board.
If you station required both the driver amp and the ATU we recommend mounting the driver amp inside
whatever is driving the Hardrock-50. Contact technical support (me) [e-mail] if you
need help with this.
Spare Part Policy
We understand that building a kit for the first time builder may have difficulty with some of the steps
and would find it easier and do a better job if they could do it a second time. To that end if you need
more wire, another core, hardware or anything just send an email and we’ll send a replacement. Spare
parts are included with the kit; we don’t know which ones you’ll need so we can’t put them in the box.
Contract Manufacturer Yield
The driver amp printed circuit board is fabricated, assembled and tested at a contract manufacturing
facility in China. The bare PCB’s are 100% electrically tested before the parts are put on. The
manufacturer that we use to put the parts on the PCB’s reports an 85 – 95% yield when assembling a
board. This means that about 1 in 10 boards will have some manufacturing defect with the SMT
assembly. This usually shows up as an unsoldered component. Since we can’t test the boards before we
send them out it means that there is a chance that we will have to find and repair something on one of
the boards. Don’t worry, by this point we know where to look and we’ve got your back. If it turns out to
be something that you can’t handle we’ll fix it for you. A working driver is included in the purchase
price.

2
2. SPECIFICATIONS
ITEM SPECIFICATION
Frequency Range 1 – 100 MHz
Input Power 0.5W maximum
DC Power 11-16 Volts, < 1.5 Amps Spec’d @ 13.8V
Amplifier Type Class A
Bias Current 400-450 mA
Size Does not affect the overall HR50 size.
Weight Adds about 6 oz.

3
3. ASSEMBLY OVERVIEW
Assembling the driver amplifier kit should be an enjoyable and rewarding experience. If at any time you
feel frustrated or are having difficulty, take a break, ask questions on the forum or email, and remember
that if you are having a problem with something there’s a good chance that someone else has had the
same issue. We have a “no questions asked” replacement part policy, so if you lose a part or need an
extra length of wire or find something missing an email is all it will take to get you a replacement.
The assembly is organized into the following subassemblies:
 Inventory
 PCB Assembly
 Integration and final assembly
The inventory information is the first thing so you can make sure that nothing is missing. There are a
few required tools:
 Soldering iron – A small temperature controlled unit is the best.
 Solder – Rosin core, fairly thin
 Screwdrivers –All of the screws in the kit are Philips
 Tweezers – For holding small parts and reaching tight areas
 Wire Stripper – Some users have had trouble stripping the #30 wire. The best tool I have found
for this is the Ideal Industries 45-125 T7 Single Wire T-Stripper, 22-30 AWG. It costs less than
$15.
 Long-nose pliers – For general mechanical assembly and crimping pins
 Toothpick – For unbraiding coax
 Digital Volt Meter (DVM) – for setting the bias current. Preferably equipped with a millivolt DC
scale.
In a production environment, an assembly station would also include an anti-static mat and all work
would be performed while wearing an anti-static wrist strap. If you are equipped with these, I encourage
you to use them.

4. DRIVER INVENTORY
PART ID
PART NUM
DRV_IN, DRV_OUT
1009-
0001
Q201
1005-
0001
PCB MOUNTING
1002-
0004
PCB MOUNTING
1000-
0006
PCB MOUNTING
1000-
0002
PCB MOUNTING
1001-
0001
POWER CABLE
ASSEMBLY
1012-
0001
HEAT SINK
COMPOUND
1013-
0002
DRIVER OUT CABLE
4
PART NUM
DESCRIPTION
PICTURE
0001
3.5MM TERMINAL
BLOCK 2 POS
0001
RD16HHF1
0004
¼” NICKEL PLATED
BRASS STAND-OFF 6.35
mm
0006
#4
-
40 ¼” MACHINE
SCREW 6.35 mm
0002
#4
-
40 ½” MACHINE
SCREW 12.7mm
0001
#4 MACHINE NUTS
WITH
INTEGRATED LOCK
WASHER
0001
3
-
PIN HEADER WITH
BARE WIRES
0002
PAPER SACHET
RG
-
316
PICTURE
QUANTIT
Y
2
1
1
1
1
2
1
1
6”

5
5. DRIVER PCB
This section covers the assembly of the Driver PCB. Required tools and supplies are; soldering iron,
diagonal cutters, tweezers and long-nose pliers. Carefully inspect the Driver PCB looking for poor
soldering on the SMT components.
The photos show a 2017 version of the board in which the DRV_IN and DRV_OUT labels are reversed.
Your board will have the labels corrected
□Step 1: Solder the two 3.5mm terminal blocks one at position DRV_IN and the other at DRV_OUT
on the top side. The openings in the terminals for inserting wires should face the silk screen markings
for RF and GND.

6
□Step 2: Cut the red, yellow and black leads of the power cable to 6” length, strip approximately ½” of
insulation from the end opposite the connector and tin the exposed wire. Be careful not to add too much
solder while tinning it may be difficult to insert the wire into the PCB in the next step.
□Step 3: Solder the power cable to the PCB observing the color markings on the PCB, RD is for the
red wire, YL is for the yellow wire and BK 1s for the black wire.

7
□Step 4: Remove the lower two screws in the front and rear panel of the Hardrock-50 amplifier and
remove the bottom cover of the amplifier.
□Step 5: Grip the leads of the MOSFET with pliers and bend the pins of the MOSFET forward as
shown. Make sure that the bend is in the thick part of the leads
□Step 6: Apply a small amount of heatsink compound to the flat side of the MOSFET. Insert the
MOSFET into the PCB from the back side. DO NOT SOLDER THE MOSFET AT THIS TIME! Use
the 4-40X1/4” screw and one of the keps nuts to attach the MOSFET to the bottom cover of the
amplifier.
Note: the bottom cover is NOT symmetrical. One of the holes is closer to the edge than the other. The
MOSFET should be mounted in the hole that is furthest from the edge of the cover.

8
□Step 7
□Step 8: Make any necessary mechanical adjustments then solder the leads of the MOSFET and trim
of any excess leads. The Driver is now ready for integration.

9
6. INTEGRATION
This section covers the final integration steps needed to connect the driver to the Hardrock-50.
□Step 1: Cut a 6" (15.2 cm) length of RG-316. Remove 1/2" (1.3cm) of the outer jacket from and of
each end of the cable, unbraid the shield using a toothpick or similar and twist and tin the shield wires.
Remove the dielectric from the center conductor, twist and tin the center conductor wires. The RG-316
cable is impervious to heat so tin the braid all the way around the cable to prevent fraying.
□Step 2: Attach one end of the jumper from Step 1 to the DRV_OUT connection on the driver board.
Be sure to put the center conductor in the terminal labeled RF and the shield in the terminal labeled
GND.
□Step 3: On the amp board in the Hardrock-50, remove the coax jumper from the AMP_IN terminal
block. Pro-Tip: when loosening the screws in the terminal block, keep turning the screw counter-
clockwise until you hear a ‘click’. This will make it easier to insert the wire. Attach the coax coming
from the amp board to the DRV_IN terminal block on the driver board and the DRV_OUT jumper, from
Step 2, into the AMP_IN terminal block on the amp board.

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□Step 4: Insert the power/control wire coming from the driver into the DRV/ATU plug on the amp
board.
□Step 5: Place a 50 ohm load on the output connector of the Hardrock-50, connect a 13.8V to the amp,
turn the amp on, set the band to 30M and the mode to PTT. Set the DVM to its lowest DC voltage scale,
the millivolt range if it has one. Connect the DVM’s probes to the I_SENSE points on the driver board.
The negative lead should tough the point near the ‘I’ and the positive lead should be on the point near
the ‘SENSE’.

11
□Step 6: Ground the center of the Hardrock-50’s PTT jack, placing the amp into the TX mode. Slowly
turn VR201 on the driver board until the voltage on the meter reads 0.045V (45 millivolts), within
0.005V (5 millivolts). Then remove the ground from the PTT jack, turn off the amp, disconnect the
power and the load.
□Step 7: Fit the bottom cover of the amp back into place, be careful not to pinch any of the wires.
Reinstall the two lower screws and the front and rear panel of the amplifier. You amp is now ready to
operate with the driver amp. 200-300 mW drive will produce 50W out 160-10M and 35-40W on 6M.

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7. SCHEMATIC DIAGRAM