I've never mucked around with the LED freq display before but the lower left vertical segment is out on ALL four digits of a Corsair LED frequency display. In other words, "6" looks like "5" and "8"
Barry: I have never dug into displays but most of them are multiplexed and the drive for that segment in all the digits is most likely at fault. Look at the display drawing and it should show what
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Wed, 06 Apr 2011 16:17:14 -0500
I just checked the Corsair manual. Definitely multiplexed and on two boards so it could be the connection of that segment between the boards, the driver chip, or the counter chip. Page 3-27 in the ma
Barry, When you say "all four" digits, I presume you mean the 100kHz, 10kHz, 1kHz and 100Hz digit positions? They are driven by a multiplex arrangement where the same segment in all digit positions i
Thanks Jerry, Clayton and Steve! What was throwing me for a loop is that the Corsair II manual really messes up this section - the text is copied from the Corsair I manual but the counter logic circu
The path you need to check is: Pin 17 of U2 on the 81247 Display Driver board R14 on the 81247 Display Driver board Links between the 81247 Display Driver board and the 81248 Display Board 73, Steve
Barry, That is odd. I don't think it can be the 68705 because that doesn't operate down at the segment level. On the other hand the 10MHz and 1MHz positions are fed by completely separate driver chip
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Wed, 06 Apr 2011 16:43:44 -0500
Corsair or Corsair II? Your post says Corsair. There is not much in common between Corsair and Corsair II displays. My post is based on the original Corsair schematics where ALL the digits come from
Sorry for the confusion - it's a Corsair II _______________________________________________ TenTec mailing list TenTec@contesting.com http://lists.contesting.com/mailman/listinfo/tentec
Wallah. Good advice. On a scope, the segment driver line looked good. So I fiddled the cable from the 68075 coming in (probably not the problem) and fiddled the board connectors that sandwich the dri
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Wed, 06 Apr 2011 18:27:20 -0500
Fortunately for fixing but unfortunately for needing fixing, TenTec cables have been a weak part of the radios for a long time and still are in Orion I and II. Best I can figure from the manual (whic
Author: Daniel Schlieper <daniel.schlieper@tuxomania.net>
Date: Thu, 7 Apr 2011 10:07:23 +0200 (CEST)
Hi Barry, I had the same problem with my Corsair II and replaced C6 on the logic board. Now all is fine. See http://www.tentecwiki.org/doku.php?id=561dispfix and pictures at http://qrpforum.de/index.
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Thu, 07 Apr 2011 11:50:05 -0500
And you jiggled the connections. No doubt C6 is highly suspect and cause of many display problems. It probably should be replaced before it goes completely bad to save on future failures. 73, Jerry,
There are so many caps just like C6 in the Corsair II, yet it seems to be a universal culprit. Wondering if there is some reason why that specific part is being abnormally stressed? == And you jiggle
I had a lot of display problems during the years my Corsair II was not used much. After re-capping the display board back in the late nineties and using the Corsair II as my PSK-31 radio almost daily
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Thu, 07 Apr 2011 23:33:53 -0500
Its the only capacitor in the radio accompanying digital logic. Everything else is analog with slower edges or no edges at all. And most of the RF bypasses are not electrolytics. 73, Jerry, K0CQ ____
Author: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Date: Thu, 07 Apr 2011 23:39:25 -0500
All electrolytics need power at least every couple years. The electrolyte eats away at the insulation layer formed after they are assembled. So they go downhill continuously while not powered. That f