Radio Shack PRO-43 Modifications FAQ
CONTENTS
1. Introduction
2. Which units can be modified for extended frequency
reception?
3. Companies that will modify the PRO-43 for extended
frequency reception
4. The modifications
extended receive (original mod + solderless)
keypad beep delete
improved audio
attaching an S-meter
400 memory channels
--------------------------------------------------------------
1. Introduction
Because there is a continuing demand for it, this mini-FAQ
about PRO-43 modifications will be posted every two weeks
until there is demand for its removal. In large part, it is
the file PRO43.MOD from pub/hamradio/mods/tandy at
oak.oakland.edu .
The FAQ now includes mods for
(1) extended receive (original mod + solderless)
(2) keypad beep delete
(3) improved audio
(4) attaching an S-meter
There is also a mod for 400 memory channels, but, to quote
its author, it is very complicated, should only be attempted
by someone with moderate to advanced electronics experience,
and is not for the faint of heart or the "weekend technician."
A brief description is included at the end of this FAQ. If
the mod were included in its entirety, the size of the FAQ
would be increased four-fold.
--------------------------------------------------------------
2. Which units can be modified for extended frequency
reception?
Note: In the United States, it is against the law
(Electronics Communications Privacy Act of 1987, public law
99-508, amended 1994 by public law 103-414) to listen to
cellular or cordless telephone communications. However, it is
not illegal to own equipment that can receive or can be
modified to receive such communications, even though it became
illegal as of April 1994 to manufacture or import equipment
that could be easily modified by the user to receive cellular
communications. Equipment manufactured before the cutoff date
can continue to be sold until stocks are exhausted. While
businesses are forbidden from importing cellular capable
scanners for resale, the question has been raised whether an
individual can legally import such equipment not intended for
resale. The issue is not explored here.
Which PRO-43 units can be modified for extended receive?
Units sold in the US and Canada can be identified by the
following scheme
Modifiable | Nonmodifiable
|
serial number no A in # | begins with A
FCC-ID AA020-300 | AA020-300A
Inside the battery compartment is a paper label containing the
date of manufacture in the form "month A year". For example,
5A3 is May, 1993. The cutoff date after which units could no
longer be modifiable is April, 1994 (4A4). So far, the
earliest reported date of manufacture of a nonmodifiable unit
is 3A4 (March, 1994). [There have been *no* reports of a
modifiable 3A4 unit.]
It has been reported that some units currently being made
for sale overseas can be modified for extended 800 MHz
reception. However, it is not known whether this applies to
all overseas units or, if not, whether there is a way to
distinguish modifiable units from nonmodifiable units.
The PRO-43 was produced under two brand names. My 3A3
unit carries the Realistic name; my 12A3 unit carries the
Radio Shack name. At the moment, it is not known whether this
represented a changeover or whether both types were produced
side-by-side for a time. It is also not known whether their
electronics are different.
There are no software modifications for the PRO-43. It is
not possible to extend the frequency range of the radio by
pushing buttons on the keypad. Such modifications are
possible with other models, such as the PRO-51, but *not* with
the PRO-43. The PRO-43, made by GRE (General Radio
Electronics) of Japan, is one of Radio Shack's few triple
conversion units. Radio Shack scanners with software mods are
double conversion units made by Uniden.
Modification procedures for other radios are available by
anonymous ftp from the pub/hamradio/mods/<manufacturer>
subdirectories at oak.oakland.edu.
There is some debate about whether step (5) of the
extended receive modification is worthwhile. According to Bob
Parnass, from his "Improved Audio Mod", below:
"Now that I have a schematic, I see that the European
version of the PRO-43 has different coils and
capacitors in the low (mid) band front end filter.
That explains why the 75 MHz sensitivity isn't stellar
after adding diode D3 to enable 30-88 MHz coverage."
So, if you trash the diode in step 4 or want to quit while
your ahead, don't lose sleep over it. On the other hand,
quoting ray_reese@tscnet.eskimo.com (Ray Reese),
When I purchased my PRO-43 and did the mod for adding
54-88 Mhz, using the removed cell. diode, I wanted to
be able to listen to the sound carrier for the tv
channels 2-6 as well as the 72-76 Mhz band. It is
worth the trouble to make the mode and it does work
well in my area, despite not having the correct coils
for that band area. Do the mod anyway, but [if you've
trashed your original diode], use a 1N4148 fast-
switching diode. Perhaps a 1N914 might do the job
also. They can be found at Radio Shack for a cheap
price.
--------------------------------------------------------------
3. Companies that will modify the PRO-43 for extended
frequency reception
If you'd rather not do the modification for extended
frequency reception yourself, Cellular Security Group, 106
Western Avenue, Essex, MA 01929 (508/768-7486) will do it for
$40, which includes insured UPS return postage. However, CSG
will not move the diode to extend the low band to 88 MHz; they
only remove the diode to unlock the 800 MHz frequencies. When
CSG is mentioned on the net, two types of comments follow:
testimonials from satisfied customers and comments from those
with the technical skills claiming that the service seems high
priced for just removing the diode. But, there have been *no*
reports of shoddy work or damaged radios. (They've modified
two of mine.) Units are processed within 24 hours of receipt.
Grove Enterprises' newly advertised Repair Service will
perform the mod for $40 plus shipping. They will move (rather
than just remove) the diode in units that can benefit from it,
but state that there is no way to tell whether the diode
should be moved without looking inside. They claim that the
determination can not be made from the serial number, FCC-ID,
or date of manufacture. For further details, call Grove at
704/837-7081. In order to get a unit modified, a service
order number must be obtained from the same telephone number.
Packages without a SO# will be refused.
--------------------------------------------------------------
4. The modifications
From: armille@afterlife.ncsc.mil (A. Ray Miller)
Summary: cellular (870-890 MHz) and low band (51-88 MHz) restoration for PRO-43
A few people have mentioned the cellular mod for the PRO-43; it turns out
you should not remove but MOVE the diode. Doing so allows cellular coverage as
well as low band (up to 88 MHz) coverage.
Acknowledgments to Grove Enterprises; this information came from them.
They are selling the PRO-43 for $300 which is $50 less than Radio Shack.
I have no connection with them other than as a satisfied customer.
PRO-43
Cellular Frequency Restoration and Low Band Expansion
Note: It is not lawful to monitor cellular or conventional mobile telephone
conversations.
The following procedure requires familiarity with microcircuit soldering and
will violate your warranty. Grove Enterprises assumes no liability resulting
from its attempt, nor will accept the modified scanner for return under any
condition.
TOOLS NEEDED: Fine point, low power soldering pencil; solder wick or a
desoldering tool; pointed awl, hemostats or pointed tweezers; small Philips
screwdriver; solder.
1) Remove the battery, antenna and back cover (held in place by four screws).
2) Remove the six screws holding the top circuit board in place. Carefully
unsolder the two antenna connections from the board. Bend the antenna ground
tab fully up from the board. Carefully lift the board, unplugging the black
connector at its base, and lay the board out of the way on its bundle of
colored wires.
3) Remove the two screws from the next board and lift it, carefully unplugging
the white connector at the bottom of the board. Lift it up and lay it aside on
its brown wire (which can be unplugged if necessary).
4) Unsolder and remove the metal shield from the final board, revealing the
microprocessor; note the row of diodes labeled D1-D5 above it. Only diodes
D1, D2, and D4 are present; assisted by a pointed tool, unsolder and remove D4,
the lone diode (this restores cellular frequencies which will be searched in 30
kHz steps).
5) Resolder the removed diode carefully into position D3 to extend low band
coverage to 88 MHz.
6) Reassemble the boards, paying particular attention to the alignment of the
plugs. Test the radio by entering any frequency between 870 and 890 MHz
(cellular) and 51-88 MHz (low band).
--
A. Ray Miller
arm@super.org | armille@afterlife.ncsc.mil
-------------------------------------------------------------------------------
From: IN%"savage@dg-rtp.dg.com" 2-FEB-1995 17:55:07.31
BTW, I did something similar [to the mod that follows] but MUCH
easier... No soldering, removing antennas, PCBs, etc..
Just open up the Pro 43 and look down on the bottom PCB from where the
batteries usually lie. You'll see the diodes there. Simply take an
xacto knife and and break the solder on the D4 diode (left-most on
mine) on the side facing you. I just cut back-and-forth for a bit.
Once the solder (it's surface mounted) is weak enough, I just bend up
the diode a bit from the PCB. Presto. I left mine hanging on the one
side with solder. If you continue to work it a bit, you can probably
remove the whole diode.
--Ed
---
From: springel@umich.edu (Jason G. Springel)
Subject: MODing a Pro-43 without soldering
I just purchased a new Pro-43 to replace my Uniden 200XLT after reading
many of the praises for the Pro-43 on this newsgroup. I decided to try
and MOD it, but don't have a lot of experience with a soldering iron.
After examining the scanner's innards, I found it was quite easy to
"fix" with nothing more than a minature philips screwdriver and some
small needlenose pliars.
************ Standard Discalimer from other MODs:
1-It is against the law to monitor cellular or mobile telephone calls.
*****2-Procedures outlined below [DO NOT] require knowledge of
microcircuits, soldering and assembly techniques.
*****3-You will [NOT] need a low-wattage soldering iron, solder and
other various tools to help in the procedure.
4-The following procedure will void your warranty.
*********************************
Here is my new MOD:
Step 1
Remove the battery, antenna, and back cover which is held in place by
four screws. Place the scanner keypad-side down on your working surface.
Step 2
Remove the six screws holding the top circuit board in place.
Step 3
Using a VERY small screwdriver (I used one from a Radio Shack kit),
remove the two screws from the lower circuit board. Looking down at
the unit, you will see that the screw on right side of the lower
circuit board can be easily removed. Remove the screw on the left side
by by sliding the screwdriver between the top circuit board and the
metal frame which holds the two boards together.
Step 4
With these two screws removed, you can now lift the entire top panel
(antenna, volume, and squelch knobs) along with the top two circuit
boards as one unit. The two circuit boards will be connected to the
final circuit board (the one attached to the front section of the
scanner) by several wires. Simply set the top panel/circuit boards
alongside the front section of the scanner and you can leave these
wires connected.
Step 5
The microporcessor is located under the large metal shield on the final
board (the front section of the scanner with the display and keypad).
If you look under metal shield from the side closest to the bottom of
the scanner, you should see the row of diodes labeled D1-D5.
Only diodes D1, D2 and D4 should be present.
Use a small pointed tool to break off D4. You actually don't have to
remove it completely (unless you want to use it to restore additional
frequencies as explained in other MODs), you can just lift one side so
it dosen't make connection and then put a small piece of tape or heat
shrink over it, so it won't. Make sure it's not lifted to high or the
boards will not fit.
This will restore Cellular Frequencies in 30 kHz steps.
Step 5
Reverse the process to replace the top panel/circuit boards and the two
screws that connect the lower circuit board. Replace the 6 screws from
the top board. Replace the cover, etc.....
...the diode positions on the cpu board, of which only three are
filled look like this. Where X equals a diode soldered in place.
D5 D4 D3 D2 D1
O X O X X Normal configuration
O O O X X Cellular modification(D4 removed)
O O X X X Lo-Band modification(D4 in D3's place)
These directions were based on an original MOD design whose origins I
do not know. My thanks go out to the original author of that MOD!
Hope this helps those of you who do not own a soldering iron!
-------------------------------------------------------------------------------
From: ross@novax.llnl.gov
Date: 19 Aug 92 16:51:08 GMT
Here is my keypad beep delete mod for the RPO-43:
1. Remove battery.
2. Remove back cover (4 screws).
3. Remove top board (6 screws, desolder two antenna connections and bend
antenna ground lead up out of the way). Be careful of black connector at
bottom of board. Flip board over and lay aside (wire connectors need not be
disconnected).
4. Remove middle board (remove 2 screws and wire connector). Be careful of two
multi-pin connectors along underside of board. Set middle board aside.
5. Locate 10 pin connector on side of bottom board (labeled CN3). Note that one
end of connector has pin 10 labeled as such. Count back to pin 6 and bend
pin 6 ninety degrees towards the large RF shield. Make sure the bent pin
clears the RF shield.
6. Reassemble and your done OR do the cell mod since you are so close.
Have fun. Gary Ross >usual disclaimer>
-------------------------------------------------------------------------------
Subject: Improved audio for the PRO-43 portable scanner
From: parnass@cbnewse.cb.att.com (Bob Parnass, AJ9S)
Date: Wed, 2 Dec 1992 01:15:35 GMT
IMPROVED AUDIO FOR THE PRO-43 SCANNER
by Bob Parnass, AJ9S
The Radio Shack PRO-43 scanner audio is too bassy.1 The
lack of treble makes it difficult to hear the PRO-43 in
noisy situations, especially while listening in a car
or truck. Louis Shirley sent me a schematic and sug-
gested I remove C341, a tiny 0.015 ufd surface mount
capacitor.
I'm glad to report that removing C341 made a great
improvement. The audio is now much "crisper," more
like the Uniden 200xlt, although still not quite as
loud. Turning the volume control up still overloads
the PRO-43's small, internal speaker, but there's less
need to do that once C341 is removed.
The PRO-43 contains 3 printed circuit boards, and the
middle (second) board contains the audio circuitry.
Finding C341 is difficult, as it is neither marked with
a value nor a component designation. It is located on
the foil side of the middle board, under IC304, an
LM386 amplifier IC. C341 is in parallel with, and phy-
sically next to, R350 (33,000 ohm). R350 is slightly
larger than C341 and is marked 333. Both R350 and C341
are connected between pin 2 of the LM386 and ground.
A Note About 50-88 MHz Reception
Now that I have a schematic, I see that the European
version of the PRO-43 has different coils and capaci-
tors in the low (mid) band front end filter. That
explains why the 75 MHz sensitivity isn't stellar after
adding diode D3 to enable 30-88 MHz coverage.
__________
1. See "PRO-43 Product Review," by Bob Parnass, AJ9S, in
the November 1992 RCMA Journal.
--
==============================================================================
Bob Parnass, AJ9S - AT&T Bell Labs - parnass@ihlpm.att.com - (708)979-5414
-------------------------------------------------------------------------------
Subject: S-Meter for PRO-43
From: schuster@panix.com (Michael Schuster)
Found this on the Fidonet scanner echo:
=====begin quoted text=================
Date: 02-06-93 00:24
From: Bill Cheek
To: All
Subject: PRO-43 S-Meter!
Greetings Scanner Fans!
It had to happen! The fundamentals for an S-Meter exist alive and well in the
PRO-43! Only a simple circuit and your choice of meter, analog or LED, is
required for a jim-dandy S-Meter function!
The key point in the circuit is the cathode of D-302 located on the bottom
(solder side) of the AF Board (middle board). You will need the Service
Manual for the PRO-43 to find it as it's not marked and it would take me
10,000 words to guide you to exactly where it is located. Call Tandy National
Parts at (800) 442-2425 to order your manual: approx $10. Now here is the
deal:
Locate D-302 and either build the following circuit right there on the back of
the AF board in the vicinity of D-302, or solder a wire to the cathode of
D-302 and route it to somewhere else more convenient to feed the below
circuit. This wire ought not to be very long, though, say not more than a
couple of inches. Refer to the ASCII schematic diagram as follows:
PRO-43
PRO-43 D-302 existing
T-302 x---o--|<-------x PRO-43 ckt
/ |
Connect |
here | 0.01-uF 1N34A
|------||------o-------->|----o---o-----------> (+)
| | |
| \ | To the
| 47-k / | S-Meter of
| ohms \ = 0.01-uF Your Choice
| / | (This should
| 1N34A | | be a jack
|-----|<-------o---o----------> (-) mounted on
^ PRO-43 Ground^ the case of
Legend: the scanner.
|
1. ---||--- and = are 0.01-uF capacitors; disk, mylar, monolythic, chip
|
2. --->|--- and ---|<---- are germanium diodes, 1N34A
| is cathode
< is anode
3. o means a connection, preferably soldered
4. The 47-k resistor is self-explanatory, I hope.
5. -------- and | are wires/conductors.
|
|
6. x is existing PRO-43 circuitry
If you use an analog meter, preferably a real S-Meter like salvaged from an
old junked CB rig, then rig it as follows to connect to the circuit above:
5-k Trim Pot
(+) --------/\/\/\/\---o--------|
| | |
This should |-------| |
be a plug of +
some sort to The S-Meter
connect to the Terminals
mating jack on -
the scanner |
|
(-)-----------------------------|
You can also build the 10-segment LED S-Meter as shown in Volume 2 of
my SCANNER MODIFICATION HANDBOOK, available from leading mail order
radio dealers everywhere. ISBN 0-939780-14-3 published by CRB Research
Books, Inc. Commack, NY.
After connected and working, locate the PRO-43 very near a known strong
transmitter, perhaps a ham transmitter, a police cruiser, your favorite
security guard's handheld or right next to a cordless telephone, or anything
else known to transmit a strong signal. Tune the scanner to the frequency,
and adjust the 5-k trim pot above so the meter reads exactly full scale. All
other signals will read proportionally lower to yield "relative signal
strength" measurements! A hell of a circuit here, boys & girls! Have fun!
Developed & distributed by: Bill Cheek
COMMtronics Engineering
PO Box 262478
San Diego, CA 92196-2478
Ok to distribute, but credit appreciated. Thanks!
Bill Cheek
--- GEcho 1.00/beta+
* Origin: Hertzian Intercept, San Diego (6pm-1pm) 619-578-9247 (1:202/731.1)
======end quoted text====================
--
_______________________________Mike Schuster________________________________
NY Pub. Access UNIX/Internet: schuster@panix.com | 70346.1745@CompuServe.COM
The Portal (R) System: schuster@shell.portal.com | MCI Mail,GEnie: MSCHUSTER
----------------------------------------------------------------------
From: bbb@kuhub.cc.ukans.edu (LORD BB)
Subject: PRO-43 w/400 CHANNELS HERES HOW!
IT IS NOT FOR THE FAINT OF HEART however.
PRO-43 ENHANCEMENT
MEMORY EXPANSION & "FADE-AWAY" LIGHT
Brett Bennett 4/12/94
bbb@kuhub.cc.ukans.edu
Copyright 1994 B&D Electronics All Rights Reserved
INTRODUCTION
The following document details two enhancement modifications that are
possible on the Radio Shack PRO-43 scanning radio. The first modification
doubles the factory standard memory capacity, allowing you to enjoy an
additional 200 channels of memory, plus 10 more monitor memories. After
completing the first modification, it is a fairly simple matter to add a 7 to
10 second delay feature to the LCD back-light lamp circuit. I designed and
performed these modifications on my PRO-43 and they do work. As I understand
it, there (has been/is being) presented in WORLD SCANNER REPORT a similar
memory expansion. I have not seen this modification and for all I know it is
a better way of doing it. What is presented is a 'clean-room' design of my
own that to the best of my knowledge is the only one to also offer a time-
delay for the LCD back-light. Having said that, let me say:
I ASSUME NO RESPONSIBILITY FOR ANYTHING THAT MIGHT HAPPEN TO YOUR RADIO
SHOULD YOU OR ANYONE ELSE ATTEMPT THESE MODIFICATIONS. WHILE REASONABLE CARE
HAS GONE INTO THE PREPARATION OF THE FOLLOWING DOCUMENT, I CAN NOT GUARANTEE
THAT THERE ARE NOT ERRORS.
The procedure described below is very complicated, and involves the soldering
and desoldering of very tiny components and the cutting of printed circuit
board traces. While the procedure is not irreversible, it will leave
permanent scars inside your scanner. It should only be attempted by someone
with moderate to advanced electronics experience. I don't think it should be
attempted by, to quote someone else, a "weekend technician." If as you read
through this you feel intimidated by the jargon and required procedures or if
an electronic schematic looks like a strange piece of modern art to you, then
this might not be the 'mod' you are looking for. The following document will
assume you have obtained the materials listed below, especially the Service
Manual, and you have studied the circuit in some detail. I will not describe
in great detail where every component is or where every solder point on the
logic board should be placed. Having the Service Manual, and having studied
the drawings therein will allow you determine to where it is I refer.
REQUIREMENTS
1 - PRO-43 Service Manual. (Tandy Parts # MS-2000300 - approx. $6.00)
1 - CD4053 - Triple - SPDT analog switch - Surface mount package (DigiKey
#CD4053BCM-ND - approx. $1.50)
2 - 93C67 EEPROMs (Tandy Parts # MX-8050 - approx. $13.00/each)
1 - 100k x 5 resistor network. Common lead type. (DigiKey # Q5104)
1 - UN2111 PNP transistor (Q1 on Logic PCB. Tandy Parts # )
1 - 1 uF 16v capacitor.
1 - 10 MOhm 1/8-1/16W resistor.
Misc.:
Wire wrap wire-30 gauge. (Radio Shack)
Grounded soldering iron with approx. 1/32" tip or smaller.
Desoldering Equipment.
Digital Volt Meter. (Used to double check your VCC and Ground connections,
pre-check switching assembly)
Utility knife with fresh sharp small blade. (Needed to cut traces.)
Strong hand held magnifying lens. (Needed to check solder joints.)
+5-10 Volt bench power supply. (Used to check switching assembly.)
Anti-Static work place and grounding wrist band.
Very fine needle nose pliers, wire cutters.
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