Newsgroups: alt.radio.scanner
From:
[email protected] (Interpol)
Subject: Uniden Bearcat 200XLT Scan Speedup Modification
Message-ID: <
[email protected]>
Sender:
[email protected]
Organization: Northwestern University, Evanston, Illinois
Date: Fri, 13 Mar 1992 18:21:58 GMT
Lines: 80
Speeding up the scan/search rates for the Uniden BC-200/205 XLT
You will need a small crystal or ceramic resonator in the 600-800
kHz range.
1. Disassemble the unit to access the microprocessor area.
a. Slide off the battery pack.
b. Remove the two screws from the rear of the scanner and the
two screws that hold the battery retaining spring at the
base. Then remove the spring.
c. Carefuly pry the bottom of the rear cover from the scanner
and remove the cover.
d. Locate the two small screws at the base of the circuit board
and remove them. Gently pull the front panel from the main
frame at the base and separate them. If you separate them
between the two layers. Remember that for later reassembly;
the pins will have to be lined up perfectly before you slip
the sections back together.
2. Search around the logic/CPU board (Uniden calls it the "MICOM
PCB Assembly"), and locate Y-201, which is a little rectangular
component. This is the stock 400 kHz resonator. Your
replacement can be a bit larger if necessary, but not grossly
so.
3. Carefully desolder and remove Y-201. Put it in safekeeping
because you may want it for something else someday.
4. Install (solder) your newly procured replacement clock
resonator, be it a crystal or another ceramic resonator, where
Y-201 came out.
5. Reassemble: Insert top of the front panel into the slot under
the volume/squelch control panel. Carefully noting the alignment
of the dual in-line connector at the bottom of the board with
the mating socket, press the front panel firmly into place. Be
sure that the holes at the bottom of the circuit board line up
two screws and tighten them
6. Replace the rear cover by inserting the top of the cover into
the slot under the VOLUME/SQUELCH control panel. Press cover
into place. Insert and tighten the screws.
7. Reposition the battery retaining spring (slotted side toward
notched hole). Insert the two remaining screws and gently
tighten them.
8. Slide the battery pack into place. Switch scanner on to
ensure that the display comes on. If not, the battery may be
discharged or the dual in-line connector may have been
misaligned during reassembly (step 5). Another possibility
would be that the new resonator either doesn't work, is
unsuitable, or may have been incorrectly installed. Another
possibility (if you installed something greater than 800 kHz
is that it's just too fast.
Assuming that the display comes on, leave the antenna disconnected,
and run a speed test. Speed in channels-per-second equals the number of
channels divided by the time in seconds. Using a Murata-Erie 800 kHz
Note that the channels must have frequencies programmed into them.
"Empty" or 0000.000 MHz channels run faster and throw off the
calculation.
In addition to the shortened delay time, the user reports that the
panel lamp will "time out". Doubling the clock frequency halves the
"light on" time. There is a variable extended delay modification in the
"World Scanner Report", to large to duplicate here. Also, in Volume 1,
Number 4, Bill Cheek reports that the UC-1147 CPU has the necessary
large chunk of memory on board, so you're stuck with 200 channels. You
can get the WSR from:
COMMtronics Engineering
PO Box 262478
San Diego, CA 92196
The Scanner Modification Handbook I and II are available from the
same address. They're something like $17.95 each + $3 P&H. The WSR is
$25 per year.
NOTE : I am not responsible for anything that goes wrong. Note that this
Newsgroups: alt.radio.scanner
From:
[email protected] (Interpol)
Subject: Uniden Bearcat 200XLT Battery Indicator Modification
Message-ID: <
[email protected]>
Sender:
[email protected]
Organization: Northwestern University, Evanston, Illinois
Date: Fri, 13 Mar 1992 18:58:15 GMT
Lines: 161
Here's some mods to help remedy the 200XLT's low battery indicator/blank out
feature, courtesy of Bob Parnass:
BC200XLT LOW BATTERY FIXES
Troy T. Pummill, N6XMV
Here are two small articles from MT. I have not tried these
mods, do so at your own risk (i.e. your milage may vary).
From Monitoring Times
Bob's Tip of the Month
May 1990, page 98
BC200XLT SHORT BATTERY LIFE SOLVED
Short abttery life--sometime only an hour or two between
charges--seems to be the only major complaint amoung owners
of the laeading hand-held scanner, the Uniden Bearcat
BC200XLT. Presumably, owners of similar sets like the
BC100XLT BC205XLT, and Cobra 4030 could have the same prob-
lem. Now that is an ailment of the past.
It turns out that the batteries were not really at fault; a
zener diode which determines the voltage at which the low-
battery indicator would come on was defective in some units,
causing the circuit to actuate prematurely. Replacing that
idode and changing the value of an associated resistor pro-
vides the answer.
FREE FIX
MT contacted Uniden and was assured that they will provide
the fix for free, even if the radio is outside of the one-
year warranty period. If your Uniden BC200XLT suffers from
short battery life, send the radioo along with a brief note
describing the ailment, to Uniden Customer Service, 9900
West Point Drive, Indianapolis, Indiana, 46250.
As shown in the accompanying diagram, zener diode D203 and
resistor R208 are the parts in question. D203 should be
about 7 volts and R208 should be 150,000 ohms. These are
miniature surface-mount devices on double- sided circuit
board; if your radio is under warranty, attemping this fix
yourself will void that warranty.
-| D203
-|-------////--------;------------|>---------------;
-| R208 | HZK3CLL01TR |
150K | |
| |
| -------------
| | |
| | | TK11750
| -| | | (printed
| -|------| IC202 | sideways)
| -| | |
| | |
| | |
| -------------
|
|
|
SHORT CUT
Mark Machcinski of Wyandotte, Michigan, came up with hisw
own solution. He simply soldered a wire bridge across diode
D203, disabling the low battery indicator entirely. The
radio now operates uninterrupted until it blanks out when
the abttery level drops to about 4.5 volts.
Yet another suggestions from a Canadian reader would bridge
the original diode with a 6.8K resistor, defeating the
premature recharge signal, yet preventing the battery from
too low a discharge.
From MT
June 1990, page 98
Bob's Tip of the Month
BC200XLT BATTERY LIFE EXTENSION: Part II
Every time we run a helpful hint on a popular product, some-
one find an even more helpful hint! This one disable the
low battery cutoff circuit and adds several hours of opera-
tion to a single charge. Our lab unit was still going
strong after seven hours straight! Uniden will provide the
fix for free, but if you're in a hurry and don't mind void-
ing your warranty, read on!
NOTE: This modification should not be attempted by anyone
unfamilier with small circuit oard components.
The tools: You will need a small Phillips screwdriver,
fine-tip soldering iron and solder wicking braid.
The procedure: Remove the battery pack, then the two screws
form the bottom spring clip. Carefully pull the rear cover
off, bottom first. Remove tjhe two small screws at the base
of the circuit board. Pull the front panel away from the
mainframe, bottom first.
At the bottom of the remaining board--to the left of the
speaker magnet--are two blue electolytic capacitors; just
above them are two striped components-- one resistor and one
diode. Using the soldering iron and braid, carefully remove
the two components without overheating the board or damaging
the copper traces.
When you reassemble the radio, be very carful to note the
insertion of the front panel into the slot at the base of
the volume/squelch panel. Be especially careful to align
the screw holes perfectly, allowing the two rows of fine pin
contacts to mate correctly with the socket. If this is not
done correctly (and it probably won't be the first time!) no
damage will occur, but the scanner display will be blank.
Recharge your batteries after 6-8 hours of heavy use. If
the scanner dies, recharge it as soon as possible to prevent
loss of your memorized frequencies.
__
||
||
------
| | Voltage Regulator PARTS LOCATOR
| |
------
[][][]
___
[___] resistor
___
[___] diode
------
- -
- -
-- -- - -
- - - - - -
-- -- ------
capacitors (2, round) Speaker Magnet
---
==============================================================================
Bob Parnass, AJ9S - AT&T Bell Laboratories - att!ihlpm!parnass - (708)979-5414
----------------------------------------------------------------------------
| Drew S. Cheng, BA '91 MD '95 | "Compelling, yet tedious...I |
| Northwestern University | feel spent, like a man who is |
| Medical School, Chicago, IL USA | forced to wear his genitals |
| IRC : "Interpol" | like a pendant." |
| Internet :
[email protected] | - Dieter, "Sprockets" |
-----------------------------------------| |
| Got any anime stuff? |
-----------------------------------
Newsgroups: alt.radio.scanner
From:
[email protected] (Interpol)
Subject: Uniden Bearcat 200XLT Cellular Restoration Mod
Message-ID: <
[email protected]>
Sender:
[email protected]
Organization: Northwestern University, Evanston, Illinois
Date: Fri, 13 Mar 1992 19:05:11 GMT
Lines: 105
Yet another Uniden/Bearcat 200XLT modification, courtesy of Bob Parnass and
other good people:
BC200/205XLT CELLULAR RESTORATION
Note: It is unlawful to monitor cellular telephone conversations. It is
possible to monitor signals from the deleted ranges even without conversion.
Simply add 21.7 MHz to the deleted frequency and enter the higher (image)
frequency. Reception is virtually identical in strength to that which would be
heard on the deleted frequency.
The frequencies deleted at the factory may be restored, but the procedure must
not be attempted by anyone unfamiliar with electronic circuitry. Grove
Enterprises assumes no liability for damage caused by this procedure. The
modification will void your warranty.
TOOLS REQUIRED: Small Phillips screwdriver, small wire cutters.
1. Slide off the battery pack and remove the antenna from the scanner.
2. Using a small Phillips screwdriver, remove the two screws from the
back of the scanner, the two screws which hold the battery retaining spring at
the base and the spring itself.
3. Carefully pry the bottom of the rear cover from the radio and remove
the cover.
4. Locate the two small screws at the base of the circuit board and
remove them. Gently pull the front panel from the mainframe at the base and
separate them.
5. Locate the (64 pin quad flatpack) microprocessor IC labelled "UNIDEN
UC-1147" and the 10k ohm (brown-black-orange) leadless resistor positioned
above the letters "DEN" on the IC.
6. Using miniature wire cutters, cut the resistor body in two without
disturbing anything else near it. If the left solder pad comes loose, it may be
peeled from the board. Brush or blow away any residue. This completes the
restoration.
REASSEMBLY
7. Insert the top of the front panel into the slot under the
volume/squelch control panel and, noting carefully the alignment of the dual
inline connector at the bottom of the board with the mating socket, press the
front panel firmly into place. Be sure that the holes at the bottom of the
circuit board line up with the holes in the plastic standoffs below them.
Insert the two screws and gently tighten them.
8. Replace the back cover by inserting the top of the cover into the
slot under the volume/squelch control panel; press the cover into place, insert
and tighten the screws.
9. Reposition the battery retaining spring (slotted side toward notched
hole), insert the two remaining screws and gently but securely tighten them.
10. Slide the battery pack into place; switch the scanner on to make
sure the display comes on. If not, the battery is discharged or the dual-inline
connector was misaligned during assembly (see step 7).
Assuming the display comes on, press: MANUAL, 845.0, E; within two seconds, the
frequency 845.000 should appear on the display.
Cut this resistor
|
V
[*10k*] [ ]
I I I I I I I I I I I I I I I I I I I
= =
= =
= =
= =
= U N I D E N =
= =
= =
= =
= =
= U C - 1 1 4 7 =
= =
= =
= =
I I I I I I I I I I I I I I I I I I I
Pete Simpson, KA1AXY
[email protected]
Data General Corp
Westboro, MA 01580
(508) 870-9837 "My company doesn't have anything to
do with this."
that's it.............et.
Edward Thomas, N2IHN.
P.O.Box 3233
Long Branch,NJ. 07740 UUCP: rutgers!petsd!tsdiag!ka2qhd!n2ihn
----------------------------------------------------------------------------
| Drew S. Cheng, BA '91 MD '95 | "Compelling, yet tedious...I |
| Northwestern University | feel spent, like a man who is |
| Medical School, Chicago, IL USA | forced to wear his genitals |
| IRC : "Interpol" | like a pendant." |
| Internet :
[email protected] | - Dieter, "Sprockets" |
-----------------------------------------| |
| Got any anime stuff? |
-----------------------------------
Newsgroups: alt.radio.scanner
From:
[email protected] (Interpol)
Subject: Uniden Bearcat 200XLT 136-174 AM Modification
Message-ID: <
[email protected]>
Sender:
[email protected]
Organization: Northwestern University, Evanston, Illinois
Date: Fri, 13 Mar 1992 19:34:40 GMT
Lines: 39
Here's the last of the 200XLT mods I know of...downloaded off of a local BBS
here in Chicago:
Modification for Putting BC-220XLT In AM Reception Mode
I have come up with a crude mod for the BC200xlt scanner to allow AM
reception in the 136 to 174 range. Why would I want AM in this range you
ask? well I attend several Air shows during the year and the Thunderbirds
use 140 mhz area fregs. As we all know the Uniden switches to FM in this
range, causeing very distorted reception (slope detection). Somebody else
may have already thought of this idea (you?) but here goes. Break the AIR
Trace between dual diode D31 and IC1 pin 8. Connect the center of a single
pole - double throw mini switch to the trace leading back to IC1 pin 8.
Connect one of the other poles to the trace leading back to D31. This is the
"Normal" mode(This just restores what you have cut). Now connect the other
pole to the VHI (VHF HI) line at a easy to locate point. This is the "AM"
mode. What will happen now is when AM is selected the VHF and VHF air band
will all be in the AM mode. UHF and others are not affected. When in the
normal mode everything is just like it always was. I have done this mode
over a year ago so it's still a cloudy in my memory. But it works like this:
The microprocessor sends a high to Q7 to select the AIR mode, by routing the
VHI signal around D31 by means of the switch the AM detector is reselected.
Normaly D31 blocks out the VHI signal allowing FM in the VHF HI range. I
hope my explaination of this mod is clear. It does take some delicate
surgery to do. I also hope I haven't duplicated anyone elses idea.
Thanks
From: BILLY WIGGINS
----------------------------------------------------------------------------
| Drew S. Cheng, BA '91 MD '95 | "Compelling, yet tedious...I |
| Northwestern University | feel spent, like a man who is |
| Medical School, Chicago, IL USA | forced to wear his genitals |
| IRC : "Interpol" | like a pendant." |
| Internet :
[email protected] | - Dieter, "Sprockets" |
-----------------------------------------| |
| Got any anime stuff? |
-----------------------------------
