James, The voltage at KIO2 pin 11 (/RXD) will be determined by your computer's input to U1 pin 6. First check the voltage at U1 pin 6 and also J1 pin 3 with the computer cable connected and the computer powered on.
Under normal conditions (computer RS232 output at idle), the voltage at U1 pin 6 (and J1 pin 3) should be somewhere between -3 volts and -25 volts (RS232 Mark voltage). If that condition is true, then the voltage at KIO2 U1 pin 11 should be 5 volts. Alternately, if the voltage at U1 pin 6 is between +3 volts and +25 volts (RS232 space voltage), then U1 pin 11 will be at 0 volts. So---, if you have the correct voltages at KIO2 in 3 and U1 pin 6, but not at U1 pin 11, then the U1 chip is not functioning properly - but if you do not have the correct voltages at U1 pin 6, then blame your computer or the cable or the L3 inductor (or a soldering short on the KIO2). If the voltage at U1 pin 6 is somewhere between +3 volts and -3 volts, and the voltage at J1 pin 3 is the same, then your problem lies with your computer serial port - this voltage region is 'indeterminate' and can result in U1 pin 11 being either at 0 volts or +5 volts (it is anyone's guess which one it will be). Once you obtain a proper input to U1 pin 6 from the computer, you can then trace the signal to the K2 control board U6 pin 26, but until you obtain +5 volts on KIO2 U1 pin 11, the zero volt reading at all points may be exactly right. As a side-note, the schematic markings are not consistent between the base K2 and the KIO2 (and KPA100) - the KIO2 schematic properly indicates the inversion in the receiver by naming the signal '/RXD', while the K2 schematic names this same signal by its non-inverted designation 'RXD' - it is a bit confusing if one is attempting to follow the logic levels - the signaling state for the RS232 level is the 'space' condition which will result in a logic low (zero volts) on the '/RXD' (or 'RXD') signal lines. 73, Don W3FPR > -----Original Message----- > > Gary, > > I took some measurements: > > You mentioned when the K2 is not sending or receiving data that U1 pin > 11 and pin 12 should both be 5 volts. Pin 12 is 5 volts, but Pin 11 is > 0 volts. I also verified that U6 Pin 25 is 5 volts and U6 Pin 26 is 0 > volts. What could cause U6 Pin 26 to be 0 volts? > > U1 Pin 5 is -10 volts, which is within the range you specified. > > I verified the serial cable is built exactly to the manual's > instructions. I verified that nothing is crossed by popping off the > covers on each end and plugging the male/female into eachother. All > colors lined up. I verified continuity with all pins. > > I tried changing between U6 - 25 and U8-4 for the side tone source in > the menu back and forth several times with no change in the output > voltage of that U6 Pin 26. If that pin is supposed to be 5v and it's > not, that seems to be raising a red flag, correct? > > Where should I go from here? > > Thanks & 73, > > James Kern KB2FCV > > -----Original Message----- > From: [EMAIL PROTECTED] > To: [EMAIL PROTECTED]; [EMAIL PROTECTED]; elecraft@mailman.qth.net > Cc: [EMAIL PROTECTED] > Sent: Fri, 27 Oct 2006 8:15 PM > Subject: W3FPR: RE: [Elecraft] KIO2 sends out to pc but doesn't take > commands from pc > > Anything less than 10 ohms means the RFC is OK. > > > Here are more KIO2 troubleshooting tips: > > > BEGIN: > > > Here are some things about testing the KIO2: (also applies to the KPA100 > RS232 interface) > > U1 pin 12 (K2 /TX) and U1 pin 11 (/K2 RX) come from the K2's U6 MCU, > pins 25 > (TXD) and 26 (RXD) respectively. All of these pins are held near 5VDC > until > they become active with data, at which time the level goes toward > ground for > short duration pulses of data. > > U1 pin 5 should be at -6 to -12VDC with no cable connected between the > KIO2 > and computer. If not, check for shorts on the pin or an unsoldered > connection. Use an ohmmeter to test for shorts with the power turned > off. > Make sure you are counting the pins correctly. Make sure your serial > cable > is built exactly like it is shown in the manual, and you did not > miscount > the pins on the DB9 connectors. Male and Female DB9 connectors are > mirror > images of each other. > > Since the MCU in the K2 must be set up to use pin 25 as a data port, be > sure > the sidetone and the SPOT button works in CW mode. Otherwise, U6 pin 25 > may > be setup as the sidetone source and not as a data pin. It is changed > between > the two, by editing the ST L Menu entry and pressing the DISPLAY button > until U8-4 is seen rather than U6-25. You may have to switch off the > power > after you make this change if the sidetone still doesn't work, and > repeat > the process several times if it is unsuccessful. > > Once you get the proper 5V level on the KIO2's U1 pins 11 and 12, you > can > use an oscilloscope or even the lower AC volts range on a voltmeter to > see > if data is present when you send a command from the PC or the K2. You > can > follow the data from the PC to the KIO2 to J1 pin 3, U1 pin 6, then U1 > pin > 11. Note that the small RF chokes on the KIO2 are fragile and can break > so > they are an open circuit. Use an ohmmeter to verify all of them have > less > than 10 ohms series resistance with the power turned off. > > Look for wiring problems too, and small strands of wire on the boards > (or > the cable connectors) that might be causing shorts to nearby circuits. > Reheat or resolder the connections if necessary. > > The idea here, is to verify there is data coming from the PC to the > MAX1406, > and then it is making it through U1 to the K2's MCU. Study the signal > labels > and pins names on J1 and U1 on the KIO2 or KPA100 schematic and you > should > be able to understand the data flow. > > Example: TXD on J1 pin 2 means transmit data from the KIO2 to the PC. > RXD on > J1 pin 3 means receive data from the PC to the KIO2. U1 buffers this > data > and then sends or receives it to/from the K2 MCU on the U1 pins labeled > /K2 > TX and /K2 RX. The "/" indicates these are active low pins, normally > held > near 5VDC until data is present. > > -- > 73, Gary AB7MY > ========= > [EMAIL PROTECTED] > Elecraft Technical Support > > > > > -----Original Message----- > From: Don Wilhelm [mailto:[EMAIL PROTECTED] > Sent: Friday, October 27, 2006 4:23 PM > To: [EMAIL PROTECTED]; elecraft@mailman.qth.net > Cc: [EMAIL PROTECTED] > Subject: RE: [Elecraft] KIO2 sends out to pc but doesn't take commands > from > pc > > > James, > > Have you checked the resistance across the tiny inductors on the KIO2 > board? > Those inductors are easily damaged when installing, and an open inductor > would cause exactly the symptoms you report. RXD and TXD are separate > signals, so it is quite possible that TXD is working, but RXD is not - > resulting on 'one-way' communications. > > 73, > Don W3FPR > > > > -----Original Message----- > > > > I have been working with the KIO2 for a while to try to get it to > > work. It's never really worked since I put it in. > > > > Today I verified with another PC that the K2 does indeed send data > > through the KIO2 but it does not receive. I ran the test as described > > on page 14 of the KIO2 manual. Steps 1,2,3,4 works fine I get the > > FA0xxxxxxxx; to come up in hyperterminal when I hit the DISPLAY > button > > as instructed. When I try step 5, which is to type SW01; then nothing > > happens. The software I tried cannot connect to the K2 either. > > > > The settings on my serial port (COM1) in Device manager (windows 2003 > > production) are as follows: > > Bits Per Second: 4800 > > Data Bits: 8 > > Parity: None > > Stop Bits: 2 > > Flow Control: None > > > > I am still baffled by what would cause one way communication, but not > > two way communication between the K2 and the PC. > > > > 73, > > > > James KB2FCV > > > > -- > No virus found in this outgoing message. > Checked by AVG. > > > > ________________________________________________________________________ > Check out the new AOL. Most comprehensive set of free safety and > security tools, free access to millions of high-quality videos from > across the web, free AOL Mail and more. > > > -- > No virus found in this incoming message. > Checked by AVG Free Edition. > Version: 7.1.408 / Virus Database: 268.13.17/505 - Release Date: > 10/27/2006 > > _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
