From cbfsb!cbnewsc!rats Tue Oct 29 13:34:00 EST 1991 Article: 10849 of rec.radio.shortwave Newsgroups: rec.radio.shortwave Path: cbfsb!cbnewsc!rats From: rats@cbnewsc.cb.att.com (PRO-2006) Subject: PRO-2006 and PRO-2022 Cellular Conversion Instructions Organization: AT&T Bell Laboratories Distribution: usa Date: Tue, 29 Oct 1991 15:50:41 GMT Message-ID: <1991Oct29.155041.26619@cbnewsc.cb.att.com> Lines: 116 PRO-2006 Modifications NOTE: The Electronic Communications Privacy Act of 1986 makes it unlawful to monitor mobile telephones, including cellular. The following modification is intended only to restore continuous 760-1300 MHz coverage as originally provided by the design of the PRO-2006 microprocessor. BE SURE TO TEST YOUR PRO-2006 FULLY BEFORE ATTEMPTING THIS MODIFICATION. ANY MODIFICATION MAY VOID YOUR WARRENTY. 824-851, 869-896 MHz Frequency Restoration Tools Required: small Phillips screwdriver, small wire cutters. Procedure: With the power cord unplugged, remove the two rear cabinet screws holding the upper cover. Lift off the upper cover, being careful not to stretch the speaker leads. Examine the inner, right-hand-corner of the front panel to find two glass diodes, labelled D503 (upper diode) and D502 (lower diode). Using the clippers, very carefully snip the visible lead of the lower diode (D502) at its bend and slightly separate the cut ends. If it is ever necessary to send the radio back for warrenty repair, the diode leads should be carefully resoldered. Reassemble, plug in AC cord, turn on scanner, and press RESET. Keyboard Beep Delete With the top cover removed as described above, locate connector CN3, a 15-pin connector with colored wires at the front of the main circuit board. There are two precedures which will stop the beep tone from being heard through the speaker; read both to decide which procedure you want to follow. (1) Find the center grey wire coming from CN3 and cut it midway to disable the beep tone. You may wish to solder a resistor in series to reduce the beep volume, a trimpot to vary the volume of the beep tone, or a minature switch to choose between beep and no beep. (or) (2) Using a pair of needle-nose pliers, CAREFULLY pry the plug from CN3, revealing a row of pins. Locate the center pin (#8) which corresponds to the grey wire and bend it down flat, disabling the beep circuit. Reinsert the plug. The pin may be erected again later to restore the beep tone if desired. This completes the restoration procedure. Reattach the cover and replace the screws. WARRANTY REPAIR Should it be necessary during the first year of ownership of your new PRO-2006 to exercise your warrenty, it should be carefully double-boxed (as you received it) and returned to Grove Enterprises. Be sure to include a copy of the original bill to establish warranty privileges. You must prepay only shipping and insurance; return shipping and insurance to you will be paid by the dealer. Grove Enterprises, P.O. Box 98, 140 Dogbranch Road Brasstown, NC; 1-704-837-9200 ========================================================================= Cellular Restoration on the Realistic PRO-2022 The Realistic PRO-2022 certainly is a look-alike for the all-time popular, but now-discontinued, PRO-2005. But is the similarity only cosmetic? What tricks can be done to increase the utility of the lower-cost 2022, now availible from Radio Shack and Grove Enterprises? Of the greatest interest, can cellular phone coverage, censored at the factory, be restored? Yes. After removing the two upper back screws and the top lid, locate the black cable just behind the front panel. Adjacent to the cable are four diodes locations: D42, D43, D44 and D45. D42 is not present; installed, it adds the 68-88 MHz European mid band (which includes the US 76-82 MHz mid band), removing the US 30-54 MHz low band. Even if a switch were installed to allow the diode to be selected, additional components and realignment are necessary for that higher frequency coverage. Don't do it! D43 is present, allowing the 800 MHz band to be received; the diode may be deleted so that the same microprocessor may be used in scanner modles which don't have that 800 MHz capability. Don't touch it! D44 is present, deleting the cellular mobile and base frequencies. If one lead is cut, total 806-960 frequency is restored, including 30 kHz steps in the cellular band. Keep in mind, however, that mobile telephone eavesdropping is prohibited by the Electronic Communications Privacy Act! This modification may void your warrenty; it is best to cut the lead carefully, gently separating the gap slightly so that it may be resoldered in case the radio needs warrenty repair later. D45 is not present; installed, it makes the cellular 30 kHz increments change to 12.5 kHz. A small SPST switch connected in series with one lead of a 1N914 or 1N4148 could allow selection of the 25 kHz step interval in those areas which utilize that channel spacing. To do this, it is necessary to unsolder a shield under the circuit board which covers the solder pads for the diodes. Such a modification should only be attempted by someone familiar with electronic circuitry. [Excerpted from Monitoring Times, June 1990, page 89.]