[TenTec] AF/IF board (was: Corsair II sidetone mod)

[Glenn]

Hi Barry,
Thanks for the encouragement. Perhaps this will be a good winter project. 
It would be awesome if I could talk Jerry into doing the board layout.
The design work is finished and I wish you could hear the audio from my Cosair II with the 
Bur Brown OP amps; it's sharp, crisp and clear. IF you have ever listened to a Racal 6790GM on SSB, I would rate the 
audio even better. Compared to a regular Corsair audio stage it's literally night and day difference. 


What I would need to do is verify my notes and schematic and see if Jerry could be persuaded to do the layout. This is an area
that I am slow in and based on the SUPERB job he did with the layout of the display board, I am convinced he could do the work very well.


Keep in mind also, I have between 30 to 50 of all 21 IC's on the Omni 6 logic board. Several of these IC's are not available at Digikey, Mouser, Allied, Newark nor Jameco. I found an overseas company who probably has the worlds largest NOS IC Inventory.
Since I don't have permission yet from Ten Tec, I will not burn the 27C64 and 27C256 EPROMS. However, I do have about 60 of each in stock if anyone wanted to burn a spare set for their own consumption.
I know Ten Tec does have and sell those EPROMS should anyone need them.


On the boards I repair for clients, I install machined IC sockets wherever I remove a defective IC. I have 3 logic boards that I have installed machined IC sockets
in all 23 positions. These are my test bed boards. 


On my test bed, I stack machined sockets to raise an IC above the clutter of cables and connectors on the board. Then I install my custom ZIF, Zero Insertion Sockets, for troubleshooting. As an example, I can raise U1 and clamp on my custom 40 pin adapter that goes to my Logic analyzer. Then I can exercise the encoders and front panel switches to look at at the buses for faults. 


As it turns out the pins on a ZIF socket are designed to be soldered to a board and are to wide to fit into a machined socket. Even too wide to fit into a leaf socket. So, I developed a technique to hand solder all of the ZIF pins to the top side of a machined socket. Once I developed this technique, it was not to bad to make even 40 pin mates. Now the ZIF will plug into a machined socket on the board or I can raise it up by stacking sockets if I need more room. Remember ZIF's are wider and longer than sockets by a considerable amount.


Glenn WA4AOS


DSM Labs (dot com)



-----Original Message-----
From: Barry N1EU <barry.n1eu at gmail.com>
To: Discussion of Ten-Tec Equipment <tentec at contesting.com>
Sent: Sat, Oct 15, 2011 2:53 pm
Subject: [TenTec] AF/IF board (was: Corsair II sidetone mod)


On Sat, Oct 15, 2011 at 9:33 PM, Glenn <wa4aos at aol.com> wrote:

> A few years back, I rewired the audio path of one of my Corsairs with Bur 
Brown IC's and the improvement in the audio was awesome. I have doe the same for 
a few clients and they also loved the mod. I had considered redoing the entire 
AF/IF board in the Corsair II but just have not had time.
>

Glenn, I can't encourage you enough to proceed with the AF/IF project.

Lately my focus has been on the AF side and I drifted from the Corsair
II to the Omni 6.  The AF strips in both radios are throw-away and I'm
in the midst of replacing everything in the Omni 6 except for the dsp
sidetone (everything else in the dsp + notch + af output goes).  It is
just amazing when you unlock the potential in these radios that was
hidden/mangled by bad AF circuitry.

73, Barry N1EU
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