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From: parnassNewsgroups: alt.radio.scanner From: Bob Parnass, AJ9S Subject: BC855XLT Organization: AT&T Bell Laboratories, Naperville, IL Date: Thu, 29 Jul 1993 18:43:19 GMT Summary: Repost of 855XLT Modification For 100 channels and full 800 MHz. Here is a repost of John Wilkerson's article from Feb 1993 on modifying the Uniden 855XLT. DISCLAIMER: This article is listed for the technically curious. No guarantees are stated that the modification listed below will work on all scanners of this model Uniden BC-855XLT Modification by the Scope of modifications. 01. Allow continuous 800 MHz receive. 02. Increase channel capacity from 50 to 100 channels. ADD 4.7K - 22K Ohm 10K Ohm works 1/4 watt carbon resistor between diode D201 and lower connection of Jumpers 3 and 4. Jumper 3 - 100 channels. Jumper 4 - 800 MHz. 01. Remove 5 screws from bottom of scanner case. 02. Carefully separate case top and bottom. 03. Unplug connector to the internal speaker. 04. Locate diode D201 and 4 jumpers near edge of circuit board. 05. Cut the 3rd and 4th jumpers near the middle and fold down the leads, if necessary. 06. Connect the lower part of jumper 3 and 4 to one end of a 10K Ohm 1/4 watt carbon resistor, insulate all exposed leads. 07. Connect the other resistor lead to the lower connection of diode D201, do not cut any leads on D201. 08. Make sure all exposed leads aren't touching any other connections, insulate as required, tack in place with a dab of RTV silicone, or low temp hot glue. 09. Reassemble scanner, make sure to plug the speaker back in. You should now have a scanner with 100 channels numbered 01-00 in 5 banks of 20 channels and continuous 800 MHz coverage. WARNING: Doing the modification to jumper 4 removed 75 percent of the 800 MHZ Band on my Scanner. Replacing the jumper restored the coverage to design limits, without harming the Scanner. My serial # is 25021343. I suspect different boards have been used in this scanner. ADDITION: My scanner had the jumpers depicted However, there were 2 more jumpers after those depicted. Disregard any additional. johnw Copyright 1993, Bob Parnass, AJ9S AT&T Bell Laboratories - parnass Source QRZ: The Windows Ham Radio CDROM |
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