++++++++++++++++++++ Date: Thu, 13 Jun 2002 16:11:01 -0400 From: W2AGN To: elecraft at mailman.qth.net Subject: [Elecraft] I Went and Did it Now-corrected That last message was a test, to see if you could read a new language. Here it is without the typos....Sorry 'bout that. I was bent about the K2, and didn't proofread I guess I really screwed up. I was getting my K2 (trusty #023) ready for FD. I was hooking up my old laptop, to send CW with TR log. Something happened, and I got 12V on the outside of the serial connector. Note this didn't go to the KIO2, but to my interface, with a transistor to key the K2 in CW. I key through the mike jack PTT line, as I use the same interface for T/R switching on PSK. Always worked fine with the big computer. I had already set the key menu for straight Key, as I used it with the big computer a week or so ago, no problems. Anyway, the voltage difference has blown something in the K2. When I turn it on, it is stuck on transmit. It appears something on the control board is blown. I have it apart, but not sure where to start. Nothing appears fried. I tried tracing the "PTT/DOT" line on the schematic and just got a headache ;-) Anybody "been there, done that?" -- _ _ _ _ _ / \ / \ / \ / \ / \ John L. Sielke w2agn at w2agn.net ( W )( 2 )( A )( G )( N ) http://www.w2agn.net \_/ \_/ \_/ \_/ \_/ NJ-QRP #57 QRP-L #884 QRP-ARCI ARQrp #86 EX-N4JS, W4MPC, W7JEF, K3HLU G-QRP #9544 NorCal CQC AKQRP QCWA FISTS #2781 SOC, ARLHS, OOTC, Zombie #576 Elecraft K2 #0023 K1 #146, 1151 ++++++++++++++++++++ Reply-To: "Ron D'Eau Claire" From: "Ron D'Eau Claire" To: Subject: Re: [Elecraft] I Went and Did it Now? Date: Thu, 13 Jun 2002 13:21:35 -0700 > I guess I really screwed up. I was getting my K2 (trusty #023) ready for FD. -- snip -- > > Anybody "been there, done that?" I'm happy to say that I haven't been there nor have I done that, but I took a look at the schematic diagram. The /DOT PTT and /DASH lines go to the Control Board where they are held at a "high" by two 82 k resistors in RP4. They are at the right end on the connector on the schematic. The /DOT PTT and /DASH lines go straight to the MCU, U6 at the RD6 and RD7 inputs. My guess is that you "fried" the MCU with the voltage. Your interface probably pumped significantly more voltage into the key lines than the normal bias provided by 5A. Normally, I'd use a simple transistor switch to ground to key the rig electronically, with the collectors only receiving what voltage is provided by 5A through those 82 k ohm resistors. Ron AC7AC K2 # 1289 +++++++++++++++++++++ Date: Thu, 13 Jun 2002 16:46:32 -0400 From: W2AGN Subject: Re: [Elecraft] I Went and Did it Now? To: Ron D'Eau Claire , elecraft at mailman.qth.net On Thursday 13 June 2002 16:21, Ron D'Eau Claire wrote: > > My guess is that you "fried" the MCU with the voltage. Your interface > probably pumped significantly more voltage into the key lines than the > normal bias provided by 5A. Normally, I'd use a simple transistor switch to > ground to key the rig electronically, with the collectors only receiving > what voltage is provided by 5A through those 82 k ohm resistors. > > Ron AC7AC > K2 # 1289 Ron, Looks like you hit it. I tried substituting an old V1.06 MCU, and sure enough, it worked. The MCU I blew was V2.01B. I'll go see about ordering a new one. -- +++++++++++++++++++++++ Date: Thu, 13 Jun 2002 17:46:12 -0400 From: W2AGN To: elecraft at mailman.qth.net Subject: [Elecraft] Beware! Well, I ordered a new MCU on the elecraft web page. Sure hope I can get it in time to install for FD! Now, I checked to see what I did. I was running the K2 off a 12V supply. As I planned to use the laptop in FD, I connected it to the same 12V supply. I use a Radio Shack voltage adapter to up the 12V to 20V for the laptop. That was the problem! Everthing was OK until I connected the serial cable. Then sparks and the computer shut down, and the K2 locked up. It seems that the negative lead coming out of the RS adapter is at +12V to the negative input to the adapter. So when I connected the serial cable, it grounded this potential, causing problems. It would work OK if they were on 2 separate batteries isolated from each other, but the RS DC Adapter is bad news anyway, with that so called negative output being so far above ground. -- +++++++++++++++++ Date: Fri, 14 Jun 2002 00:14:46 -0000 To: "W2AGN" , "Ron D'Eau Claire" , Subject: Re: [Elecraft] I Went and Did it Now? From: W2AGN said: > Ron, > > Looks like you hit it. I tried substituting an old V1.06 MCU, and sure > enough, it worked. > > The MCU I blew was V2.01B. I'll go see about ordering a new one. > > -- I blew my MCU while trying to get the PTT to work when I added the KIO2, so I know how you feel. But look on the bright side... If you buy a KPA100, you could get a brand new MCU, for free!!!! hi hi Logan, KZ6O +++++++++++++++++++ Date: Sat, 15 Jun 2002 18:39:23 +0000 (GMT) From: w2agn at w2agn.net (W2AGN) To: elecraft at mailman.qth.net Subject: [Elecraft] FAST Service I fried my MCU on Thursday, ordewred a new one that afternoon. I received it today, Saturday! Now that is FAST CA to NJ! Thanks, Elecraft. Old K2 #0023 is perking away again! ++++++++++++++++++++