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Re: [TenTec] Omni 6 Logic Board Failure

To: tentec@contesting.com
Subject: Re: [TenTec] Omni 6 Logic Board Failure
From: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Reply-to: geraldj@weather.net, Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Fri, 14 Jan 2011 15:49:58 -0600
List-post: <tentec@contesting.com">mailto:tentec@contesting.com>
I was looking at the wrong schematic set, the original Orion.

Found the much much simpler logic board for the Omni VI in the Omni VI 
manual. CPU is an 80C32. Still available from multiple makers. Ram is 
6264 which should be readily available and the program (8051 compatible 
code) is stored in a 27C256. I have a shoe box full of those from 
modifying packet TNCs. I'm certain I can read and write the 27C256, but 
I don't have an 8051 disassembler and haven't learned 8051 assembler 

The DSP is an ADSP 2105 with several vendors and versions.

The stinker that I see is a DS1285 real time clock chip that is no 
longer made. Though Dallis Semi/Maxim says their DS12885+ or DS12885N+ 
is a direct replacement and still made (in three packages). The N+ has 
the wider temperature range. I also see a lithium cell on the board. Has 
anyone ever replaced that cell when there was a control board problem? 
Every other radio that vintage with a lithium cell has needed 
replacement. That might be worth the bother in the Omni VI and VI+. A 
typical front panel check for a bad memory battery is that the radio 
runs fine if you do a master or major reset at power on. That's because 
the battery backed up parts are supplied with main power and the reset 
initializes them.

There might be other parts with problems but one could eliminate the DSP 
by connecting the input and output audio cables together.

73, Jerry, K0CQ

On 1/14/2011 11:09 AM, Neal Laugman wrote:
> On Fri, 14 Jan 2011 10:40:52 -0600
> "Dr. Gerald N. Johnson"<geraldj@weather.net>  wrote:
>> I was going to look at the Omni VI control board logic, but unless I
>> commit to doing a lot, the dozen or 16 schematics turned me off.
> Uh - yeah. My solution to the problem is this: Barring any intellectual
> property or licensing issues, release a version of the source code into
> the public domain and let a 3rd party manufacture the solution. This
> happens every so often in the software domain, usually creating quite a
> bit of synergy the OEM can take advantage of in their future product
> development.
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