Help needed ID-1590

[Alan 'A.J.' Franzman]

---- Original Message ----
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> From:    Fran Olson <w9uls at YAHOO.COM>
> Subject: Help needed ID-1590
>
> Help Needed                  December 07, 2006      Kit built_Nov 07, 1977
>
>   I have a Heathkit model ID-1590 digital wind speed/direction indicator
> that I built back in 1977, and just recently it quit sending the wind
> speed. The wind direction section is just fine, I need someone who might
> know how or what to look for in getting it working again, Here is what I've
> checked so far.
>   1. The 8 strand cable from transmitters to control cabinet or indoor
> unit. (OK)
>   2. Looked inside for bad solder connections. (still looks good, and
> nothing loose)
>   3. Tried testing by using the manual's test's. (failed the test) this I
> think might be the problem, but don't know if the parts are still be
> available.
>   4. The readout tube digit on the right side is strong, but I can hardly
> see the left side digit.
>
>   This might just be another heathkit to use the good old two pound sledge
> hammer on?
>
>   Fran O. W9ULS Illinois
>   w9ulsATyahooDOTcom

Please, don't smash it!

Re item #4, if one digit in the 2-digit panel works well and the other
doesn't, unless there is evidence of serious sputtering on the bad digit, the
problem lies elsewhere.  In this case, I would first check the connection at
the "socket", assuming the construction is similar to the Heath clocks that
used the same readouts, looking especially for a poor anode connection.  Next
I would check the current-setting resistor R224, and IC209 (swap with IC208
and see if problem follows chip).  In the clocks there is a high-voltage PNP
transistor on each digit's anode that is often responsible for dimming or
flickering problems, but I see by the schematic
<http://www.tech-systems-labs.com/schematic/ID-1590-new.jpg> that the anodes
for both digits are paralleled in this instance, ruling out that possibility.

Re item #3, did the speed fail to indicate with switch S1 in the "CAL"
position?  If so, you most likely have a logic failure on the board.  It
should be easy to find with the schematic and a logic probe.

Best regards,

Alan "A.J." Franzman

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