From:wa2ise@cbnewsb.cb.att.com (robert.f.casey) Newsgroups:rec.radio.amateur.misc Subject:TS440 Q33 protection Keywords:fix Message-ID:<1991Dec10.045038.26685@cbfsb.att.com> Date:10 Dec 91 04:50:38 GMT Sender:news@cbfsb.att.com Organization:AT&T Bell Laboratories Lines:59 copied from packet: Msg# TSF Size #Rd Date Time From MsgID To 8731 BF 1957 0 08-Dec 0343 KD2EJ 28523_WB2QJA INFO@ALLBBS () Sb:PROTECTING Q-33 ON TS-440S SB-949 TS-440S PROTECTI 01/20/89 If pin 7 (RL) of the remote connector is accidently connected to ground, current from the 14 volt line (14L) will damage transistor Q33 on the IF unit. This will prevent the radio from transmitting. To protect Q33, a 4.7 ohm resistor should be installed in series with the RL line on the foil side of the IF board. In the event that pin 7 is connected to ground, the resistor will open, but the transceiver will still be capable of transmitting. REQUIRED PART: 4.7 OHM, 1/6 WATT RESISTOR ........ RD14CB2C4R7J 1Disconnect the power supply and antenna from the transceiver. 2Using a #2 Phillips screw driver, remove the 9 screws from the top cover of the transceiver. Remove the cover and unplug the speaker wire. 3Locate connector 19 on the IF unit. 4Using a #1 Phillips screw driver, remove the 7 screws that secure the IF unit to the chassis of the transceiver. 5Pull the board up and rotate it towards the front of the transceiver to expose the foil side of the board. 6On the foil side of the board, locate the trace that is connected to pin 3 (brown wire) of connector 19. 7Using a craft knife, cut the trace comming from pin three so as to open the foil trace. 8Solder the 4.7 ohm resistor across the now open trace (i.e. in series with the trace). 9Assemble the transceiver by reversing steps 1 - 5. This is an optional change that may not be covered under warranty. Time required for this modification is 0.5 hrs or less. © 112188TKC ===================================================================== Note:I haven't tried or verified this, proceed at your own risk. WA2ISE  Amsterdam View Our Stats   CLICK FOR A FREE DOMAIN NAMES HTTP://WWW.YOURNAME.TK FOR YOUR OWN WEBSITE IF YOU CLICK HERE AND YOU CAN VOTE FOR OUR FREE WEBSITES IN THE TOP 100 LIST  WANT A TOP RANKING ? USE THE ULTIMATE SOFTWARE SUITE FOR WEB SITE PROMOTION  FreeWebSubmissions Submit Your Site To The Web's Top 50 Search Engines For Free THE ALEXA BANNER, THIS BANNER GIVES THE DALLY STATISTICS OF THIS FREE WEB SITE The World of Free Packet Radio Software Amsterdam The World Of Free Packet Radio Software Amsterdam The Netherlands |