Msg Nr. : 32410 Da : LU7AKC Per : NET9K6@WW Tipo/status : B$ Data/ora : 0815/0256 Dimensione : 9320 Titolo : MFJ1270 & 9600 Bps Bid (Mid) : 12258_LU7AKC MFJ-1270 & SAT. Hello Mark, Name is George. QTH: Peachtree City, GA. Saw your message and thought I would tell you about the 19200 mod. to the 1270 terminal port. I just got a 1270 and just completed this mod. It is very easy and only takes a few minutes. The modification is in the 1270 "Fast Start" handbook that I got with my 1270, but if you have an older 1270 it might not be in the book. The following mod. is in the Appendix section of the 1270 book here: 1. Remove motherboard out of the chassis . 2. Locate the dip switch SW2 ( dip switch for selecting the computer port rate and radio baud rate ) and IC U1. 3. Cut the trace between SW2 and U1. ( Note: rather than do this, I simply bent the pin # 1 on U1 out of its socket to prevent a destructive mod. ). 4. Connect a jumper from U1 pin # 10 to SW2 pin # 1 ( this is where the dip switch has its 300 baud position ). Be sure to connect this jumper wire to the "ON" side of the switch ( when the switch is in "ON" position it will close connection ). 5. Ensure that U3 is an LM384 or TL084 or equivalent. 6. Now when you select a terminal baud rate of "300" on the dip switches, you will get a baud rate of 19,200 instead. Hope this helps, Mark. Let me know if you need more info. BEST 73, George, AB4KN @ UO-22. =============================================================================== Hi there Mark, the handle here is Clarence, QTH Albert Bridge, Nova Scotia. I am sending you a file I have had for some time that I picked off AO-16 or LO-19 some time ago. It is the 19200 baud mod for the 1270, I have not tried it myself but it makes sense to me what is being done and I think it is one of the mods incorporated by a lot of the other chaps. I am using an MFJ-1278 and I have modified it using a mod I got off one of the birds and it works fine. I called MFJ and put some heat on them for a mod and they came up with a mod after many calls, that was very cumbersome. It might be worthwile to give them a call anyhow and remind them that you are using their equipment and maybe if enough people call thay will become aware that they should get into the 20th century and put 19200 baud in their TNCs. Enough soapboxing here is the mod. I have left the callsigns in there as I don't take credit for it I am just passing it on. Hope it works for you and all the best. " MOD ONE " MODIFICATION FOR MFJ 1270 TNC THIS MOD ALLOWS YOU TO USE 19200 BETWEEN THE TNC AND COMPUTER . THIS MOD WAS PROVIDED BY HB9AQZ...HANSPETER THE DIAGRAM IS BY KB8HAV...CHARLIE 1) replace U3 (LM324 or LM348) with a TL074, TL084 or MC33079P 2) Cut trace from U1 pin 2 to SW2 pin 1 (300 bps position!) see ** below . 3) Wire U1 pin 10 to SW2 pin 1 , see *** below . __________________________ When you set SW2 powition 1 to on, you get now 19200 bps terminal rate, instead of 300 bps. (300 bps is no longer available!) I placed miniature relays on the pcb near SW2 and J-4 to switch the radio and terminal rates between 1200-9600 for packet radio and 9600-19200 for UO-22, otherwise you must change the switches in the back every time you change the mode of operation! original trace ** ///////////( cut here )/////////// / | / 8 pin 2 1 x------------------ |-------------|--| sw2 > | * * * * * * * * | NEW | | U1 * | 8 7 6 5 4 3 2 1 | WIRE | |-.--------------| ----------------- *** | 9 10 16 * * * * * * * * ------x pcb 9 11 13 15 16 pcb 10 12 14 ________________________________________________ pcb = pc board con~ecti~s (pin 9 to 16 are sh~ fr refere~ce ~ly) sw2 > = Has the ~umbered sitch psitions for setti~g the baud rate. These numbers can be see~ frm the rear of the t~c . x-----------x = New wire that is added from sw2 pin1 to U1 pin 10 . This is the only wire added . ///////////// = Original trace that must be cut . It ran from sw2 pin1 to U1 pin 2 . This is the only trace that must be cut . U1 is a MC14040b in my 1270 . The only mod to U3 is to replace it . ( no trace to cut here ) ------------------------------------------------------- THE TL084CN WAS ONLY $1.50 HERE IN KENTUCKY . NOTE : This drawing is not to scale . You will find sw2 and u1 on back edge of the pc board next to 12 volt input jack. All pin positions are shown from the TOP VIEW of the pc board and the tnc LED's positioned at your chest. All cuts and connections are made on the bottom side of pc board , keep this in mind when you are identifying the needed pins. I would like to thank....Hanspeter HB9AQZ ....for this mod., it has make a hugh difference in the down load bps from UO-22 at my station. CHARLIE KB8HAV LOUISVILLE KY. " MOD TWO " Hi Clarence, Sorry to be so late with the answer, I finally found the mod! I got it from VE8DX, Bob...so here she comes back up North agn, hi! 73 Dave WB6LLO This is a relatively easy modification that can be performed to MFJ 1270-74 to allow 19.2 asynchronous communications between the TNC and your computer. First **** replace U3 (LM324) with a TLO84cn or TLO 94 FET op-amp. the LM324 craps out at 9600 Baud and is dead at 19.2k (my LM324 works fine at 19.2 k ---Dave) Cut the Pc trace that goes to Pin #2 of U1 (divider) about 1/8" from the IC itself. Solder jumper from pin 10 of U1 to the trace you have just isolated. Solder to the side of the trace that goes to pin 1 and pin 6 of the sw2 baud rate selector switch. This supplies 307.2 khz clock (19.2/16) to pin 1 whic is now 19.2 k to the modem instead of 300 baud. Turning on sw1 and sw7 will allow 19.2 k baud on the serial port and 1200 on the radio port. The 19.2k baud rate is unreliable with the pms code. We are using the TAPR 1.1.6 code (or lower without PMS and having excellent results on the serial port. The radio port is currently running at 9.6k and is connected to a Paccom nb96 modem. *********************************************** Clarence, the above is verbatim from ve8dx. I made a few additional mods on my 1274. I mounted a power switch outboard on an "L" bracket mounted to the right hand side of the modem. It is difficult to access the back of my modem the way my panel is arranged. I also mounted a three position switch that is in parallel with the dip switch on the back that selects the rate. There is room just above the con and power leds. I can now control the power and select 1200, 9600 or 19.2k from the front panel. Sori I couldn't get this to you sooner, but had a problem finding the mod. It is now filed properly, hi! 73 Dave WB6LLO San Diego, CA I suddenly realized I had two mods for the 1270/1274 so I have sent both as you are aware I am sure the only basic difference between the 1270 and the 1274 is the fact the 1274 has the tuning indicator. Have fun ... 73 ... Clarence ... VE1HD -=>