[TenTec] unstable Omni D display fix-problem found

w8bvh w8bvh at sbcglobal.net
Mon Jul 13 04:51:47 PDT 2009


Mike :
Try this site: $69.90.
http://www.donberg.ie/catalogue/semiconductors/semiconductors_md-mz/mk_50398n,ic.html
Best regards,
Ralph Howes
W8BVH

----- Original Message ----- 
From: "Mike Bryce" <prosolar at sssnet.com>
To: <geraldj at weather.net>; "Discussion of Ten-Tec Equipment" 
<tentec at contesting.com>
Sent: Sunday, July 12, 2009 9:26 AM
Subject: Re: [TenTec] unstable Omni D display fix-problem found


> the counter-on-a-chip is a MK50398N
>
> the multiplex chips are 75491APC and 75492apc
>
> there's two 491's they are the segment multiplexer and the 492 is the
> display multiplexer
>
> ( I guess technically, the 50398 does the multiplexing, and the three
> other chips are used to decode and drive the LEDS)
>
> both the 75491APC and 75492apc are not stocked anymore by ten tec.
> These chips are really hard to come by, but again, there's the part
> miners out there that have them listed, but with  $250 min to buy.
>
> I did a quick look at NTE and they seem to have a replacement for the
> 491, but have not looked deeper into the project.
>
> there's three possibilities here with a dead Ten Tec Omni LED display
>
> 1. Get another junker for parts
> 2. Use a external freq counter
> 3. The dead one becomes the part donor
>
> and...
>
> there's a few places that sell "digital dials" that maybe used,but
> none that I have seen drive LEDs, they are usually for LCD displays.
>
>
> Mike, WB8VGE
>>
> What are the chips?
>
> 73, Jerry, K0CQ
>
>
>
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