Icom PCR-1000

A post NE1H (now N1IP) and I (now K4JCW) wrote from around Feb, 1998 describing how to modify an Icom PCR-1000 for cellular coverage.

If I recall correctly, radios with S/N's > 4000 can no longer be modded this way.

RADIO: ICOM IC-PCR1000 COMMUNICATIONS RECEIVER.
 
SUBJECT: ICOM IC-PCR1000 FREQUENCY MODIFICATION.
 
You've been waiting.
 
You've been told it can't be done.
 
You don't want to pay for it.
 
Here's how you do it.
 
The PCR-1000 full coverage mod:
 
What you'll need:
Small philips screwdriver
Slightly larger philips screwdriver
Soldering iron with *very* fine tip
Xacto knife, or other sharp tool
2 0-ohm surface mount resistors, 0804 in size, or
30 gauge wire-wrap wire
No fear of surface mount components
Ability to follow instructions
 
Very very very first step.  Read ALL the steps before
starting.  Make sure you feel comfortable making a mod of this nature.
It's not rocket science, but it does require a steady hand.
 
There are three things that can happen as a result of this
mod.  1)  You're completely successful.  2) You screw up a surface
mount pad, but the radio still works when you're done.  3)  You're a
total hack using the wrong tools, and you send the radio back to Icom
for repair.
 
Hopefully, you're a result 1 type person.  At worst, you're a
result 2.  If you think your going to be a result 3 type, don't even
start.  Call a friend.
 
We've done this mod on 2 radios with complete success.  We
can't guarantee that in later radios this mod will still work.  It
works at least with serial numbers up to 1111 in the last 4 digits.
 
Let's get started!
 
Remove the 8 screws that attach the cover,  and remove the top
cover of the radio.
 
Orient the radio so that serial, power and RF connector are
closest to you, and the power switch faces away from you.
 
On the PC board closest to you, in the upper left hand corner
you should see a 80 pin surface mount chip.  It has a number such as
64F3334 stamped on it.   This is the processor.
 
Near the upper left hand corner of the chip, you should see 2
small green 0-ohm resistors.  To the left of the two resistors you
should see an unpopulated pair of pads.  These are the 3 "R"s below,
on the left.  The 4th "R" is used for location reference below.
 
 
|       RRR       R
|    o          ooo
|    o     -----------------
|    o    |                 |
|    o    |                 |  D
|         |                 |  D
|    r    |                 |
|          -----------------
|
|   ---
|  |   |
|  |   |
|  |   |
|   ---
---------------------
 
(Picture courtesy of Alan Adamson, NE1H)
 
Using the soldering iron and knife, *carefully* remove the
right hand resistor.  You'll need to alternately heat the two ends,
while apply a *light* pressure with the knife.  Once it's hot enough,
it will lift off.  It's very easy to destroy the pads the resistor is
soldered to, so be *careful*.
 
You'll now need to short the pads of the left resistor (this
is the unpopulated one).  You can either try and re-use the resistor
you just lifted (least good idea), short them with a short piece of
wire wrap wire (OK idea), or use a real 0-ohm resistor (best idea).
 
For the next step you have two options.  One option is easy
and does not require removing the board from the radio (recommended).
The other option is "more correct", but will require disconnecting all
the cables, removing the 5 screws that hold the board down, etc
(purist method).  We'll presume you're more likely to want easy, so
here are the steps for it.
 
Keeping the radio oriented as described above, look below the
right hand resistor (the one we removed).  You should see 3 vias
(holes) (see picture above).  Follow the left most via, and it should
go to the left most pin of the processor.  The second via should go to
the next pin to right, and third via should go to the pin to right.
At this point, you should see two pins that don't appear to be
connected to anything, then a pin that connects to a small black
resistor marked 201 (this is the 4th "R" in the picture).
 
If you've sucessfully located the 6 pins above, we want to
short the pin that is the 4th from the left to ground.  Above these 6
pins, you should see a small black rectangle, with 8 pins.  I believe
it is marked 220.  On the side of this part (it's a resistor pack),
there is a pin that is soldered to the ground plane.
 
To short the 4th pin from the left to ground, tack a wire to
the pin.  Be *very* careful not to short the adjacent pins to the 4th
pin.  It's very easy to do.  It you do, use a piece of Solderwick or
coax braid to remove the solder.  Better yet, don't short the pins.
Tack the other end of the wire to the pin on the resistor pack
described above.
 
OK, you'd rather do it the "more correct" way.  Disconnect all
the cables from the board.  You'll need to remove the shield from the
RF section to remove the white ribbon cables.  Disconnect the power
and speaker cable.  Remove the 5 screws that hold the PC card down.
Remove the card from the radio.
 
Orient the board as described above.  Look for the white
connector above the packet connector (lower left).  It's marked J12.
Just above that are a pair of solder pads for a resistor.  One side
goes to ground, the other goes to a via.  Follow the trace on the
bottom side of the board.  You should see that it goes to a via, but
that the trace has been cut right next to the via.
 
Using a sharp knife and a lot of care, scratch away the solder
mask to reveal bare copper on the trace.  Use a piece of wire wrap
wire to repair the cut trace (bridge the trace to the via).  Back on
the top side, short the pads for the resistor that are open (this is
the lower case "R" on the left, off by itself).
 
Reassemble the radio.  If you used the "more correct" way,
make sure you get all the screws and cables back in.
 
Plug it in, turn it on, fire up the software.  Tune a
frequency you couldn't before.  If you can tune it with the software,
and the squelch is open, you're working!
 
If it's not working, review everything we described.  Make
sure you didn't short any pins.  I can't offer you much more help if
it didn't work.
 
Remember, you screw up your radio, it's not my fault.  I don't
work for Icom, I don't represent Icom.  I don't endorse listening to
frequencies you're not supposed to, and can't be held liable for
anything that happens, anywhere in the universe, as a result of you
making this mod, or even thinking about making this mod (Gawd, I hate
lawyers.  CYA!).  This mod was done completely from our own experience
and background, and did not reference any material.  We don't know
about these people selling the mod on the 'net, but we didn't steal it
from them.
 
Hope this helps.  If you've got any suggestions to improve how
to make this mod, please send e-mail.  If you made this mod, let us
know how it went.  Also, if you want a list of the PCR-1000 commands
we know about, drop us e-mail, or use DejaNews(tm) and search the
alt.radio.scanner groups for the post (look for PCR-1000 in the
subject).
 
- Chris, KD4DTS
 
(Thanks to Alan Adamson, NE1H for his being ready and willing
to sacrifice his radio to a higher cause, and his drawing).
 
 
---
John "Chris" Wren, KD4DTS
jcwren@atlanta.com
xxx-yyy-zzzz (H)
770-840-9200 x2417 (W)
 
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