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@gmail.com>
To: Discussion of Ten-Tec Equipment <tentec@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@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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