Sorry for the confusion - it's a Corsair II
On Wed, Apr 6, 2011 at 9:43 PM, Dr. Gerald N. Johnson
<geraldj@weather.net> wrote:
> 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 the counter.
>
> On the II, the segment driver for the MHz digits is different from the
> segment driver for the KHZ and Hz digits. And so the connections between the
> boards is different. Its not likely to be a display LED problem though a
> shorted LED could conceivable blow the driver which is protected a little by
> a series resistor. I expect a bad cable connection rather than a bad IC or
> resistor.
>
> 73, Jerry, K0CQ
>
> On 4/6/2011 4:29 PM, Barry N1EU wrote:
>>
>> 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 circuitry is completely different. To their
>> credit, the correct updated schematics are included in the Corsair II
>> manual. The Corsair II uses 81246 Logic Board -> 81247 Display Driver
>> -> 81248 Display Board while the text still references 80973 Logic
>> Board, etc.
>>
>> As Steve suggests, it IS an odd fault because the megahertz digit also
>> shows the same fault so we can't easily isolate it to the driver of
>> the khz/hz digits. I'm going to try and hang a scope probe on the
>> segment line and see if it is dead back to the display driver chips.
>> If so, I guess it could be a bad 68705 or ???
>>
>> Thanks& 73,
>> Barry N1EU
>>
>>
>>
>> On Wed, Apr 6, 2011 at 9:17 PM, Dr. Gerald N. Johnson
>> <geraldj@weather.net> wrote:
>>>
>>> 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 manual I
>>> downloaded from TenTec some time ago.
>>>
>>> 73, Jerry, K0CQ
>>>
>>> On 4/6/2011 4:11 PM, Clayton Brantley wrote:
>>>>
>>>> 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 is driving
>>>> that particular segment.
>>>>
>>>> I'll look at a drawing a bit later and see if there is anything
>>>> obivious. Right
>>>> now, I'm going but the seat
>>>> of my pants. Hi
>>>>
>>>> Good luck.
>>>> Clayton N4EV
>>>>
>>>>
>>>>
>>>>
>>>> ________________________________
>>>> From: Barry N1EU<barry.n1eu@gmail.com>
>>>> To: Discussion of Ten-Tec Equipment<tentec@contesting.com>
>>>> Sent: Wed, April 6, 2011 4:00:00 PM
>>>> Subject: [TenTec] Corsair - blank LED segments
>>>>
>>>> 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" looks
>>>> like "9". Do they share something in common that would point to the
>>>> source of the trouble? Obvious things to check?
>>>>
>>>> Thanks& 73,
>>>> Barry N1EU
>>>> _______________________________________________
>>>>
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>>>
>>
>
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