The Unsorted BBS Collection/thegreatunsorted.tar/thegreatunsorted/texts/pirate_radio/bc100xlt.txt

Text File | 1994-06-27 | 25KB | 471 lines

Last modified on 5-12-94: some additional info has been gathered, and new
data collected on some mods, but these are the basics to go with.
--Sherrod

============================================================================

I'll go ahead and post the mods I know of
for the 100XLT.  These have been collected from other netters, and some of
this is discussion via e-mail with others.


Uniden America Corporation
8707 North By Northeast Blvd.
P.O. Box 501368
Indianapolis, IN 46250
Attn: Parts Department

Here's the info on current mods I've gathered:

Here's some information about the BC100XLT collected from posts and
correspondence with people more familiar with the BC200XLT.

>From mailed notes:

------------------<BEGIN LETTER FROM BRETT BOROWSKI>-----------------

Yup, it's the same CPU as thje BC200XLT.  And I suspect that most of the
pc board inside are the
same.  The 100 will not have the 800mhz sub-pc board, an extra memory chip,
and will have some jumping blocks in different places than on 200.  I'll
get back to you with the light mod.....

>                Circuit board on back of Keypad Unit
> +------------------------------------------------------------------------+
> |  o O       v--resistor              +---+              +x-x-x-x+       |
> |blue^     l l   (for battery         |400|              | SONY  |       |
> |caps      ^      mod in 200)         |EC |     x  x     | K1013 |       |
> |          |--diode                   +x-x+     x  x     +x-x-x-x+       |
> |  x                                   2 pins   x  x       4 pins @side  |
> |   \_                                          x  x                     |
> |   / \                     19 pins           unused pads   13 pins      |
> |   \_/Spkr.              +--------------+                +----------+   |
> |   /                 13  | UNIDEN       | 13         13  | LH5008TP |13 |
> |  x                 pins | UC-1147      |pins       pins |  SHARP   |pin|
> |                         | 4080FB86     |                |  JAPAN   |   |
> |                         | 9E1 JAPAN    |       text---> | 8851 A   |   |
> |                         \--------------+    is turned   \----------+   |
> |                           19 pins          90 deg CW       13 pins     |
> +------------------------------------------------------------------------+

Looks the same as the micom board in the 200. But you're missing a memory
chip-- the sony K1013.  And the jumpers on pins 15, and 19 would have to be
moved.

> +=== antenna jack
> |                   Middle removable board with metal sheild around it
> V +----------------------------------------------------------------------+
>   |  Screw hole   text printed>==+    +====<  raised board               |
> +-+   |====> O    on board       |    |     +---------------------+      |
> | |            "800 MHz UNIT" <==+    +==>  | HCT-55 94V-0        |      |
> +-| +> ___      ___      ___                | PH-066AB            |      |
>   | |  ~~~      ~~~      ~~~                | ^                   |      |
>   | 3 holes in board, seem                  | i.d. printed        |      |
>   | like holes for vertical                 |      on board       |      |
>   | circuit board add'n.      ___           +---------------------+      |
>   |   __                      ~~~                                        |
> +-+  |__|                     XTAL            +===vertical boards==v     |
> +-+   L11                                     v               _________  |
>   |   __                 __   __             ____________     ~~~~~~~~~  |
> +-+  |__|               |__| |__|            ~~~~~~~~~~~~     "IF UNIT"  |
> +-+   L7                L12  L13            "WINDOW UNIT"                |
>   +----------------------------------------------------------------------+

This also looks the same.
>
> So how similar are the guts of the 200?  Could it be that Uniden only left
> out one board which could just be soldered in place?

The guts do appear to be the same.  As far as the 800mhz, unit, there are 5
inductors and 2 caps on one side.  But 15 caps, 10 resistors, and 4
transistors on the other side.  It does not look simple to build on your
own.  I'm under the impression that the performance of this board is
critical.  My current scanner measured in at 0.5 microvolts of sensitivity
in the 800mhz region but the previous one measured about 2.  That's a
pretty wide range for a single model of scanner.

It might not be so hard to add some memory though.  One chip and moving a
jumper as far as I can tell....

> Let me know what you figure out as to if anything looks the same or might
> be moddable as you posted in you messages about pins 15, 18, and 19, and
> also the light mod.  One final question:  how do you count the pins?
> I have noted the beveled edge on the largest IC's, but don't know how
> to count the pins.

Okay, on the CPU (UC-1147), number one is the first pin to the right of the
notch.  Number 64 is to the left of the notch.  (ie, they go
counter-clockwise.)

To turn the light on, jump the transistor input that is fed by pin 63 (2nd
from the bottom on the left edge--notch to the lower right) to VCC.  Pin 26
is VCC and you should be able to trace it to a clear pad near the bottom
edge of the board (when you can read the text on the CPU).  This pad is the
alternate location for a jumper chip that should change the low band form
29-54 to 66-88mhz.  (Note, I don't know if all the inductors and
adjustments are the same in the European version which employs this
configuration.)  Well, about those light pins--pins 60-62 are also VCC.
So if you want the light on all the time, just tie 63 to the pin or pins
above it.  You can do this with one find strand of a braided wire and no
soldering if you're carely.  But your light will be on whenever the power
is on.  If you want to add a switch, solder the leads--one to that VCC
jumper block pad I mentioned, and the other to the transistor that pin 63
leads to.  I don't recommend soldering directly to the CPU--it's more
likely to be heat sensitive and those pins are pretty small.

I hope I haven't confused you.  Any more questions, just ask!

Brett
--
[e-mail]                  Brett Borowski

-------------------<END LETTER FROM BRETT BOROWSKI>--------------------

Quoted text inside above letter quote is mine (along with drawings),
while unquoted sections are his replies.

On first diagram above, the chip labeled 400 EC is the frequency control.
It operates at 400 KHz, and recently Tom Bodoh ([e-mail])
posted that he had a few extra crystals to sell which double the clock
frequency to 800 KHz.  I did this mod, and am pleased with the
faster performance.  Now it scans 40 Ch./sec., samples priority twice as
often, delay time is cut in half, and light on time is also twice as
short.  However, if, like me, you do the light mod and put in a switch,
you won't have to worry about the light part.

If you are interested in ordering the crystal for doing this yourself, and
also if you want to make your rate 2.5 times (approx) the original rate, the
manufactureer is

Murata Erie, North America, Inc.
Rockmart Industrial Park
P.O. Box 487
Rockmart, GA 30153   [phone]
M.E.N.A. Part Number CSB1000J

This is a 1000KHz crystal, instead of the original 400KHz crystal.  Results
show something around 50 ch/sec scan rate, priority sampling rate of ~.8
sec, light delay of ~6 seconds, and VHF search rate of ~3.5 sec/MHz.  To get
more reliable results, (and to be sure your scanner has more time to sample
each channel for activity and get a more accurate result), you might want to
get the 800KHz crystal, which operates with very few side effects other than
just about doubling any clock-related operation.

About adding 800 MHz reception to the 100XLT: since, as noted above, the 100
lacks a sub-board required and present in the better cousin, the 200XLT.
This sub-board is in direct line with the antenna, and I suppose its
function is to downconvert the 800MHz to a more useable frequency before it
is lost inside the sanner circuitry.  Without this board, you can move the
jumper on the CPU to let it access the 800-900 numbers from the keypad, but
there will still be no method of receiving the signals.  The circuitry
simply isn't there.

UNIDEN refused when I talked directly with them to sell the 800 MHz board.
They will sell all the parts minus the PCB itself: I purchased all the parts
for the board quite a while back, but without the PCB.  I copied the PCB
design from the 200XLT manual, and have it laser-printer ready, but have not
figured out a cheap way to do a trial board to test everything.  The board
has quite a number of plate-throughs, and three microstrip patches, and
while I did my best to copy the locations and geometries of them, copying a
microstrip patch (especially on a board of unknown permittivity,
conductivity, etc) is mainly a say-a-prayer-and-hope-it-works business.  If
I ever finish making a board and install it and try it out, I will be sure
to post results.

But the lack of the 800 MHz region seems to be the only real
difference between the 100 and 200, again other than memory
and moving a jumper (as desribed by Brett).
Since UNIDEN doesn't even sell this board to the dealers: _all_
repair work on the units has to be done in the original repair
factory, I will try to see if it's possible to generate the board myself for
areasonable cost producing reasonable results.

Notes on opening the unit :  Remove the back two black
screws, obviously: next pull off battery pack and undo the two screws
holding in battery spring in middle of bottom.  Then lift back end of
bottom of radio up slowly, pulling out a little at the same time.  it
should slide out without too much trouble.  Front cover is more
problematic: it has a header connecting the keyboard with the CPU
etc. board.  So lift up on the bottom of the front slowly, and look
inside as soon as possible for a small black rectangular box about .25"
by .75", and continue lifting slowly while watching that you don't bend
the pins.  After that, the board with the metal shielding around it comes
up with two screws at the bottom of the radio.  Reassembly is reverse
order, obviously.  Again, caution when putting front back on so that you
first insert top of front back under lip at top of radio, then make sure
to get all the pins in the header correctly.  After the first scary time
of doing it, you'll see how easy it is, and it should go faster.  Always
remember the pins on the header will bend pretty easily, though, and
that's about all the difficulties.

Hope this helps, but don't fry your radio.  Be careful about static
electricity while working inside the radio, too.



>From a post on the internet regarding the internals of the 200XLT,
which is the fully enabled version of the 100XLT:
-------------------------<BEGIN SECOND QUOTE>----------------------


There are three pins on the CPU that are jumped to ground.  (15, 18, and
19)  They are not labelled in the service manual.  The interesting thing
about these pins is that there are alternate pads on the pc board that
could jump each of these pins to VCC instead.

Being the foolhardy soul they I am, I moved each of the little jumping
blocks to find out what would happen.  The results are mildy interesting
and not overwhelmingly useful.  I was hoping I could get 30khz spacing
in the 800mhz range, but no such luck.  Two of the three reduce the
capabilities of the scanner and the third changes it. Here's what happened.


Pin 19--when grounded, allows the CPU to tune 800mhz freqs.  When high,
        nada.  This may be (actually _is_ - Sherrod's note)
        used in the BC100.
Pin 18--when grounded, low band reception is 29-54mhz.  When high,
        it's 66-88mhz.  I think this is for European markets.  Sadly,
        one can't tune 29-54mhz when 66-88 in enabled.
Pin 15--when grounded, gives 10 banks of 20 channels.  When high, the
        memory is screwy. In bank 1, you get 1-10.  It skips bank 2 and
        in bank 3, you get 21-30, bank 4, 31-40, .... bank 10, 91-100.
        Leaving you wiht 90 channels.  I would have expected 100 channels
        with 10 in each.  Elminated one memory chip and this could be used
        in a bc100.  I don't understand the 90 channels, though.

Hope somebody out there find this interesting.  BTW, I'm going to
be working on an edited version of 200 mod file and I will add the light
mod.  If there's demand, I'll post.  If not, I'll post that it's available
and email on request.
Brett
--
[e-mail]                  Brett Borowski


-------------------------<END SECOND QUOTE>------------------------
The above pins are exactly the same on the 100XLT, as they have
the same circuitry internally, minus a few critical components.

Notes about reception of 66-88Mhz: previously programmed channels are still
receieved with no problem, but moving the jumper simply controls the ability
to key in new frequencies in those ranges.  As (I believe Bob Parnass, maybe
someone else) someone mentioned somewhere on the net, since the American
version (29-54 Mhz enabled) has different coils and caps for the VHF-LO to
optimize reception of a different range, therefore moving the jumper will
allow you to receive in that range, but the scanner will be very deaf to
anything existant there, and the images from the 29-54 band will walk all
over most everything there.


====================================================================

Adding 100 Channels to the 100XLT: Instructions and parts required.


The following  instructions tell  how to  add an extra 100 channels to
your Bearcat  100XLT.   PLEASE READ THE ENTIRE FILE BEFORE PROCEEDING.
This modification  is only  meant for  the more recent versions of the
100XLT, for  those which use the same CPU board as the 200XLT.  UNIDEN
has left  off some  parts from this board, but the solder pads must be
in place for the additional parts to restore the 100 extra channels.

Before ordering  parts to modify your scanner, open up the unit to see
if your  scanner is  modifiable.   Look at  the  CPU  board  (the  one
integrated with  the keyboard  and the  display; the same one with the
UC-1147 64  pin chip).   Look  above the upper right corner of the UC-
1147 chip  (the CPU)  and see  if there  are 8  solder pads  in a  DIP
configuration; if  so, then  yours is  the later version of the 100XLT
which is modifiable.  If not, then modifying it is not recommended.

Also, if  you are  not comfortable  soldering surface mount components
directly onto  the CPU  board of  your scanner,  do not  attempt this.
Remember, it's  better to  have a  working 100  channel scanner than a
non-functional 200 channel one.
The following  parts are  necessary for  the operation of the scanner:
As of May, 1993, the prices are valid:

Qty  Stock number   Scanner part #  Description                 Cost
1    SMBC200XLT                     Service Manual for the 200  16.00
1    BDEY1127001    IC206           Memory chip                 14.74
1    BDBD1777549    Q208            Transistor                  00.64
3    BRZY0021001    R250,R252,R253  Jumper chip                 00.08
2    BRFD182234Z    R218,R219*      22Kohm resistor             00.08
1    BRFD181004Z    R222            10 ohm resistor             00.08
                                    Shipping and Handling       04.50

*note: In  the 200XLT schematic, these are 22Kohm.  In my 100XLT, R218
came as  4.7Kohm, so  I matched  R219 as  4.7Kohm.  However, using the
listed value on the 200 schematic means you would have to replace R218
and add  R219 as  both 22Kohm.  If you want to use a 4.7 Kohm resistor
to match  the current  R218, then  order part  number BRFD18472Z, also
$00.08.   Also, the  service manual  is not  required, but  is nice to
have     for      the      parts      layout      and      schematics.

Contact  the   Uniden  Parts   Department  for   current  pricing  and
availability.   They take  credit cards  and  checks,  but  obviously,
checks take longer to process (it took them three weeks to cash mine).
Uniden Parts Dept.
P.O. Box 50463
Indianapolis, IN 46250
Tel [phone]
Fax [phone]



_Procedure:_

First start  by copying  down all  the frequencies in your current 100
channels.   More likely than not, you will lose them in the process of
moving the jumpers to tell the CPU that it now has 200 channels.

Next make sure you are working in a static-free station.  If you don't
know   about    this,   you    shouldn't   be    doing    this    mod.

The IC206's  leads should  have been  trimmed to  sit flush  with  the
board: if  not, then  trim them  off to the proper length (so the chip
sits flush).

Set the CPU board so that the text on the CPU is right side up and the
speaker is on your left, with the keypad down, obviously.


                Circuit board on back of Keypad Unit
+--------------------------------------------------------------------+
|                                     +--+--empty pads               |
|                                     |  |                           |
|                             +---+   v  v     R222\ +x-x-x-x+       |
|                             |400|   x  x          v| SONY  |       |
|                             |EC |   x  x R250--v  l| K1013 |       |
|                             +x-x+   x  x      ll   +x-x-x-x+       |
|  x                                  x  x R223-^                    |
|   \_                  transistor-\..   - <-R252                    |
|   / \                             ..  - <-R219                     |
|   \_/Spkr.           +--------------+ - <-R218       +----------+  |
|   /                  | UNIDEN       |                | LH5008TP |  |
|  x                   | UC-1147      |                |  SHARP   |  |
|                      | 4080FB86     |                |  JAPAN   |  |
|                      | 9E1 JAPAN    |       text---> | 8851 A   |  |
|                      \--------------+ :    is turned \----------+  |
|                                 :l  l:l    90 deg CW               |
|                                 ^^                                 |
|          new location for R253--++--old location of 10Kohm resistor|
+--------------------------------------------------------------------+

At the  bottom right corner of the CPU, the l's represent the location
of the  jumper chips  in the  100XLT.  The :'s represent the alternate
location.   From the  left on  the bottom, the first :l combination is
the important jumper for this mod.  Remove the current 10Kohm resistor
and install R253, a jumper chip, across the pads represented by the :
Remember as  you work  with surface mounted components, they are glued
to the  board, so  remove the  solder from both ends and slowly pry up
the chip  while making  sure that the solder is liquefied on the ends,
and be careful not to pull up traces, etc.  They're pretty hard to put
back once they're gone  :)


Install the  missing K1013 chip, notch down toward the CPU.  The first
pair of  pads directly  beneath the  new chip  (one  of  the  pads  is
connected to  pin 1  of the new chip) gets the jumper chip, R252.  The
next set  of horizontal  pads get  the  22Kohm  resistor  (R219),  and
replace R218  (the next  set of  pads  down)  with  the  other  22Kohm
resistor if it is not 22K already.

Next mount the transistor directly above the upper right corner of the
CPU.   Reading the  transistor in  the same orientation as the diagram
above, the  text CI- should be upside down, such that the stripe is to
the right.

Now look  at the  left side  of the  previously existing  K1013  chip.
Immediately to  its left  in my  version was a diode: this needs to be
removed and  replaced with R222, the 10ohm resistor.  A little more to
the left  is a  open pair  of pads;  place R250, a jumper chip, there.
R223, already  installed in mine, was a 10ohm resistor (mentioned only
for location reference).

Now reassemble the scanner, taking careful not to properly realign the
pins on  the RF  board with  the socket on the CPU board.  Connect the
battery pack  and turn  the unit on; you might have to cycle it on and
off several  times to  get a display.  Enter a frequency in channels 1
and 200,  turn the  unit off,  and turn  it back  on.   If the scanner
maintains its memory, then everything else ought to work also.

If your scanner does not retain its memory, then check all your solder
joints to  make sure  they  do  not  bridge  to  any  adjacent  traces
(especially around  the transistor  and the  CPU, and  the new  chip's
leads).   Make sure  the all  the parts are properly located, checking
with the  schematic if  you were  wise enough  to get one.  Also, make
sure the  transistor and  the IC  are in the right orientation.  After
that, troubleshooting becomes your sinking boat, not mine.

For cosmetic's sake, you might want to order and replace the following
part to make the front appear the same as a 200XLT:

Qty  Stock number   Description                   Cost
1    KDPT419915Z    Display plate for keyboard    00.62

Again, check with UNIDEN for availability and the current price.

Standard postmortem disclaimer: I do not assume any responsibility for
damage you might do while inside your unit.  Nor do I claim that these
modifications will  work for  all versions of the BC100XLT.  I make no
guarantees about  the correctness  of this file, but I will do my best
to make  sure it's  right for everything I did to get my unit working.


========================================================================

Copy of AM/FM mode switch mod: mailed to me by Tom Bodoh:
neither done on my scanner, so proceed at own
risk.  They give the right idea of what to do, in case details are sketchy.

> Here's the last of the 200XLT mods I know of...downloaded off of a local BBS
> here in Chicago:
>
> Modification for Putting BC-200XLT (same for 100XLT) 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

==================================================================



This completes my knowledge of the mods for the 100XLT.  Any more additions,
please mail me and let me know so I may add them into the files...

Sherrod Munday

[e-mail]
[e-mail]
[e-mail]


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