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[TenTec] Creating public domain service manuals...

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Subject: [TenTec] Creating public domain service manuals...
From: N4LQ@iglou.com (Steve Ellington N4LQ)
Date: Sun, 14 Feb 1999 07:19:13 -0500
>Reply to wb9iog:
>In case there is some confusion, the Omni V does have good basic
>documentation, including schematics and limited circuit description, but
>what I mean by a service manual is alignment procedures,

Most alignment procedures are in the manual.

 signal & voltage
>information at different circuit nodes,

Signals at different nodes? These are rather obvious. For example. If we
inject an RF signal into the antenna jack, we should be able to see it exit
the RF amplifier etc. It's true that stage gains might prove helpful but
generally most faults result in a either/or situation.

Voltages are normally understood to be typical bias voltages for silicon
transistors ie.   .2v between base and emitter unless otherwise driven to
cut off by the T or R voltages. Collector voltages are normally near the
supply voltage and emitter voltages will vary with Emitter current which is
a function of the above.

 characteristic waveforms,

Sine waves everywhere except in the PLL.

This we don't want!

>receive sensitivity measurements,

This is given in the current manual

 Basically step by step
>tests that the factory might do when checking out a new unit, or aligning /
>checking an old one in for service.

With the exception of military equipment, I've not seen the likes of this.
Perhaps you've come in contact with some of those manuals where nothing is
left to the immagination. I remember one Mil manual that gave great details
on how to DISTROY the unit in case of ememy attack.

>My proposal was that we could take units fresh back from Ten-Tec service,
>just units known to be in good working order, and take the time to record
>this data with documentation of the test equipment and procedures used. If
>we archived this sort of information, it would make troubleshooting
>easier. I have much of the equipment required for testing

You will need a spectrum analyzer...$$$$$1000's. Digital scope with
photographing capability, calibrated output signal generator. All of which
very few amateurs have.

Take care also that your probe doesn't slip and distroy that hard to replace

and am willing to
>collect what I don't have. I'm not enough of an RF designer to troubleshoot
>it entirely from just schematics (I realize that some are), but with this
>kind of test data, I can get down to the source of a problem pretty

And there you go, Gathering some of that data does require an engineer who
can interept scope patterns, stage gains, describe circuits better etc.

>I'm a pretty good digital/computer engineer, but I've never done much
>RF/analog design and I'm trying to learn more.
>Actually I've got my Omni V in for service right now and am planning to
>these sort of measurements on it when it comes back for my own use.

I think that's a good idea but again, be careful with that probe.
>I hope this clarifies what I'm looking for.

It's a good cause and good that you have the time to do it.

Steve N4LQ

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