[TenTec] Corsair - blank LED segments

[Steve Hunt]

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 chips and components from the other 
positions. I can't see anything on the schematic which is unique to one 
segmens and also common across the positions ?????

73,
Steve G3TXQ


On 06/04/2011 22:29, 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
>