Here are the mods for the pro34. I've heard it said that adding the 68-88 Mhz band might delete some other band. I haven't tried any of this, proceed at your own risk! WA2ISE The Following instructions are a result of a request for the coverage mods for the PRO-34 scanner. I made the assumption that the requester had never opened up their scanner before. The instructions below are for those that don't like to completely dissassemble every new electronic toy they buy just to see how it works. Nor is it for the guy that has been building their own equipment since the days of the first tube diode. This set of instructions assumes a moderate level of skill with a soldering iron, and some simple hand tools. It is aimed at those who just want the additional coverage from the mods but havn't been building kits for a decade. lets just call these .... "NOVICE NOTES" FOR PRO-34 MODIFICATIONS 1. Remove the 4 small phillips screws on the back of the unit 2. Remove the battery cover and battery holder from the case. 3. Remove the two knobs on the top of the case (Volume & Squelch) 4. The Case has some pressure fit points, These are at the bottom of the case and you need to be a bit careful in forcing the two halves of the case shell apart. Once you have the pressure fit points at the bottom released, angle up the bottom of the case until the battery separation wall is clear of the internal metal frame, and slide towards the top of the unit, place the back half of the shell aside. 5. Now you will see the RF board mounted to the metal support frame, The BNC (antenna) connector leads and the volume control power switch leads are soldered directly to the board. Carefully desolder these 4 connections. 6. At the bottom of the RF board there is a IF Can transformer that has a small wire as a grounding strap soldered directly to it. Desolder this as well. 7. There will be some wires from the volume control knob to the PC board that are socketed. Remove the plug from the RF board (needle nose pliers work) 8. There will also be a similar wire (small shielded ) from the squelch control to the RF board which is also Socketed. Remove the plug from the RF board. (Again Needle Nose Pliers work good here) 9. Remove the 4 threaded stand-offs from the RF Board (these Hold the RF board to the internal metal frame and are where the screws that hold the back of the case on go.) Use a nut driver or Needle Nose Pliers. 10. Now the the RF board is mostly free. The only thing holding it in is the row of connector pins on its bottom side that plug into the logic board. You will need to pry this board up gently. Be warned that the bottom side of the RF board is just chock full of Very Small surface mounted components. So use something non-metallic and smooth to do the prying with. 11. Now that you have removed the RF board, place it along with the case shell back 12. The Internal Metal support frame is now exposed. There are 3 small phillips screws holding the metal frame to the bottom Logic board (actually, these screws go through the logic board and into the front half of the case.) 2 of the screws are near the top, and 1 is at the bottom of the metal frame. remove these 3 screws. 13. There is a small socketed wire that leads from the small power pc board on the metal frame that goes under it and is plugged into the Logic board. Lift the metal frame up and remove the power plug from the PC board. Place the metal frame with the rest of your parts pile. 14. You have the component side of the Logic board exposed now. There are 2 small phillips screws at the bottom of the PC board (where the Battery compartment WAS) Remove them. 15. Once you have the last 2 screws removed the Logic board is free. The speaker wires lead from the speaker to the logic board on the bottom side. These are soldered in but there is enough play in them to allow you to make the mods. 16. NOTE: The keyboard lock switch is a funky little piece of plastic with a sliding stainless metal contactor that is just wedged in between the front case and the logic board. Remove both the switch contacts and the plastic switch. (best know it now or loose them in the carpet) 17. On the component side of the PC board you will see lots of nifty surface mounted components, a fat little barrel capacitor (used for maintaining the channel freqs while you change the batteries.. and make modifications :) near the edge of the PC board you will see a couple of small diodes mounted vertically. These will be labeled on the PC board as D10 and D11, you will also see a place for another diaode to be soldered in but was not installed at the factory.. this is D9. 18. You must now move diode D11 to the place where D9 is labled. (or just remove d11 just for cell) As you have probably noticed by now there is a tin cover over about 1/2rd of the PC boards solder side. The edge of the tin cover nearest the diodes has 2 metal tabs soldered to the PC board. Desolder these 2 tabs and gently bend the metal cover way from the solder side of the PC board. This will expose the board enough to let you get your soldering iron in to where the diode leads are. 19. Desolder the D11 diode from the bottom while pulling it away from the board on the top of the board using neadle nose pliers on the LEAD only. This does the cell mod. 20. Now heat up the D9 solder pads and insert the diode (the same way it was oriented in the D11 location) This does the 66-88Mhz mod (this may delete some other band). You Have Completed the Mods for complete 800mhz band coverage and 66-88mhz band coverage. Follow the same steps backwards (20->1)and replace "remove" with "replace" and "desolder" with "solder" N.B. These instructions are from last night, All the steps are in correct order as well as the general information. The diagrams are from memory so components may not be in the exact location indicated, but they will be very close. LASTLY, Now that you have made the mods, you can use the warranty card to light the Bar-B-Q Grill with. ########################### DIAGRAMS ############################## BNC Connector RF Board __ / / internal metal frame |- ============================= / -- | \ Logic Board |_____________________________| / =============================================================== SIDE VIEW OF RF-BOARD, METAL FRAME, LOGIC BOARD --------------------------------- | L E G E N D |----------------------------- _____________________________ | X1 BNC lead | @ X5 @| | X2 BNC Sheild Lead |_ -- | | X3 Power Switch Lead --_X1 | | | | X4 Power Switch Lead | -- | | X5 Groundig Strap to RF Can ---X2 __ | | -- | --1 | | | | RF Can Xformer with | | | -- ground wire soldered to it | | | _ | __ | | ( ) Channel Memory Capacitor - X3 --2 | | - - X4 | | __ | @ @ | | --1 Plug from Squelch Control |____________________________| | __ | --2 Plug from Volume Contol TOP OF RF-BOARD | | @ Threaded Stand-off | | * Phillips Screws ______________________________ | |* | || | | 0 Diode (vertical mounted) | | || | | | |____|| | | : Solder Location of D9 | | | | (where you move D11 to) | \| | | *| | | /| | | | | | | | | | | | | | |* | | | ------------------------------ | | TOP OF INTERNAL METAL SUPPORT FRAME | |_______________________________ -------------------------------------------------------------- | *| | | | | | _ | | ( ) | | - | | | | | | | | D9 D10 D1 | | \ / | | | :00 <-- *| |_____________________________________________________________| COMPONENT SIDE OF LOGIC BOARD ############################################################################## Here are the mods just as received from the MODS mail server ============================================================================== == Date: 4 Apr 89 14:24:01 GMT Subject: PRO-34 Scanner Modifications In the May 1989 edition of Popular Communications is a "Letter to the Editor" on the Radio Shack PRO-34 Scanner. Below is the text of that letter. PRO-34 Scanner Modification In regard to the information presented (March Issue) on the handheld Radio Shack PRO-34 scanner, my own observations on the modifications have been: 1. To restore missing 800 MHz frequencies, remove D-11. 2. To add 66 to 88 MHz (European Coverage), install a diode at D-9. 3. D-10 must remain in place for full 800 MHz coverage. 4. If a diode is added at D-13 it cuts out aero band, also seems to affect 800 MHz channel spacing. 5. D-12 added dosen't seem to have any affect. 6. Only D-10 and D-11 are factory installed. I wish to thank you for a fine and informative magazine. I have had much reading enjoyment. Sam S. Jones, Rebel Antenna, Falls Church, VA Enjoy... Mark D. Copple || 42705 Lawrence Place, Fremont, Ca 94538 || (415) 438-2028 || -/Vuarnet International/- 617/527.oo91 24oo-16.8k HST/V32bis