[Elecraft] K-2 Control Board Resistance Checks Fail
Hi all: I am assembling K-2 S/N 4397. I have just completed the Control Board. Two of the resistance checks fail. The resistance between the collectors of both Q1 and Q2 to ground measure 454 K each. They are supposed to show resistance 1meg to ground. I have checked resistor network RP1. It is installed correctly. On RP1, the resistance between 12, 34, 56, 78 and 910 are all 3.9K. Resistance checks between 23, 45, 67 are all under 1 ohm. Resistance between 89 is about 1.5k. That strikes me as an anomoly, but I'm not sure. Can anyone tell me whether this looks good, or suggest where the problem might be? Tnx. 73 de Brian W3BW ___ 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
Re: [Elecraft] K-2 Control Board Resistance Checks Fail
Hi Try reversing the ohmmeter leads or changing ranges and see if the readings look better. If not I wouldn't worry about it. You are mainly looking for gross errors like very low readings or shorts. Some DVM ohms ranges will turn on semiconductors in the circuits and that will give the effect of a lower than expected reading. Changing ranges or reversing the leads may keep the semis from conducting. Don Brown KD5NDB - Original Message - From: Brian Wrublemailto:[EMAIL PROTECTED] To: [EMAIL PROTECTED]mailto:[EMAIL PROTECTED] Cc: Elecraft Discussion Listmailto:elecraft@mailman.qth.net Sent: Sunday, August 08, 2004 1:07 PM Subject: [Elecraft] K-2 Control Board Resistance Checks Fail Hi all: I am assembling K-2 S/N 4397. I have just completed the Control Board. Two of the resistance checks fail. The resistance between the collectors of both Q1 and Q2 to ground measure 454 K each. They are supposed to show resistance 1meg to ground. I have checked resistor network RP1. It is installed correctly. On RP1, the resistance between 12, 34, 56, 78 and 910 are all 3.9K. Resistance checks between 23, 45, 67 are all under 1 ohm. Resistance between 89 is about 1.5k. That strikes me as an anomoly, but I'm not sure. Can anyone tell me whether this looks good, or suggest where the problem might be? Tnx. 73 de Brian W3BW ___ Elecraft mailing list Post to: Elecraft@mailman.qth.netmailto: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/elecrafthttp://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htmhttp://mailman.qth.net/subscribershtm Elecraft web page: http://www.elecraft.comhttp://www.elecraft.com/ ___ 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
RE: [Elecraft] K-2 Control Board Resistance Checks Fail
Thanks for the tip. That worked. One reads infinite, and the other 1.1meg when I reverse the leads. Nothing beats this reflector for nearly instant (and accurate) help and info. 73, Brian _ From: Don Brown [mailto:[EMAIL PROTECTED] Sent: Sunday, August 08, 2004 1:38 PM To: Brian Wruble Cc: Elecraft Discussion List Subject: Re: [Elecraft] K-2 Control Board Resistance Checks Fail Hi Try reversing the ohmmeter leads or changing ranges and see if the readings look better. If not I wouldn't worry about it. You are mainly looking for gross errors like very low readings or shorts. Some DVM ohms ranges will turn on semiconductors in the circuits and that will give the effect of a lower than expected reading. Changing ranges or reversing the leads may keep the semis from conducting. Don Brown KD5NDB - Original Message - From: Brian mailto:[EMAIL PROTECTED] Wruble To: [EMAIL PROTECTED] Cc: Elecraft Discussion List mailto:elecraft@mailman.qth.net Sent: Sunday, August 08, 2004 1:07 PM Subject: [Elecraft] K-2 Control Board Resistance Checks Fail Hi all: I am assembling K-2 S/N 4397. I have just completed the Control Board. Two of the resistance checks fail. The resistance between the collectors of both Q1 and Q2 to ground measure 454 K each. They are supposed to show resistance 1meg to ground. I have checked resistor network RP1. It is installed correctly. On RP1, the resistance between 12, 34, 56, 78 and 910 are all 3.9K. Resistance checks between 23, 45, 67 are all under 1 ohm. Resistance between 89 is about 1.5k. That strikes me as an anomoly, but I'm not sure. Can anyone tell me whether this looks good, or suggest where the problem might be? Tnx. 73 de Brian W3BW ___ 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 ___ 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
RE: [Elecraft] K-2 Control Board Resistance Checks Fail
Another clue that this is happening (charging capacitive loads, etc.) is that the reading will be sliding, drifting while you are watching it. If you see this, reverse the leads. Bob N4HY -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Brian Wruble Sent: Sunday, August 08, 2004 6:42 PM To: [EMAIL PROTECTED] Cc: 'Elecraft Discussion List' Subject: RE: [Elecraft] K-2 Control Board Resistance Checks Fail Thanks for the tip. That worked. One reads infinite, and the other 1.1meg when I reverse the leads. Nothing beats this reflector for nearly instant (and accurate) help and info. 73, Brian ___ 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
