[R-390] test equipment question

[Kim Herron]

Peel the covers off and look.  If the gears are cracked, you'll see it.

Kim Herron W8ZV 
www.goldenradioservice.com
kim.herron at sbcglobal.net
1-616-677-3706

-----Original Message-----
From: r-390-bounces at mailman.qth.net [mailto:r-390-bounces at mailman.qth.net]
On Behalf Of Michael OBrien
Sent: Saturday, February 14, 2009 8:52 AM
To: r-390 at mailman.qth.net
Subject: Re: [R-390] test equipment question


Hi All
I have 2 of the 8640b and like them How can you tell if the gears are
cracked or broken One of mine had been rebuilt that I bought from a guy on
ebay that does that kind of work

Mike 


--- On Fri, 2/13/09, Cecil Acuff <chacuff at cableone.net> wrote:

> From: Cecil Acuff <chacuff at cableone.net>
> Subject: Re: [R-390] test equipment question
> To: "Tisha Hayes" <tisha.hayes at gmail.com>, r-390 at mailman.qth.net
> Date: Friday, February 13, 2009, 1:22 PM
> Actually a good HP-8640B can be had on ebay for fairly cheap....don't 
> go to Fair Radio though...not the place to buy test gear....except 
> maybe scopes.
> 
> The 8640B is an analog sig gen but has a lock feature that will lock 
> it down to the dialed up freq so no problems with drift.  I would 
> imagine a working example could be had for less than $400.
> 
> I didn't like the URM-25 either and got rid of it
> quickly....  The HP-606A and a freq counter was a better solution and 
> then I added the 8640...
> 
> Cecil...
>   ----- Original Message ----- 
>   From: Tisha Hayes 
>   To: r-390 at mailman.qth.net 
>   Sent: Friday, February 13, 2009 11:55 AM
>   Subject: Re: [R-390] test equipment question
> 
> 
>   I know that this is broaching on heresy to mention this;
> 
>   I found the URM-25D to be less than helpful when compared to a good 
> signal generator. It is drifty, the impedance matching module is a 
> joke and it is hard to get repeatable results when trying to chase the 
> performance dragon.
> 
>   But; if you use a good frequency reference (like the 100 KHz 
> calibrator and that is not waay off and WWV) you can get darned close 
> to being on frequency.
> 
>   If you dare to dabble with the compensation screws on the PTO to 
> correct linearity you need a much better frequency counter and signal 
> generator. Of course, gettting used HP/Agilent equipment will cost you 
> more than any one radio would ever sell for. You can find a really 
> decent HP 400 series VTVM or a Boonton that would do an excellent job 
> on measuring RF levels for a song-and-a-dance.
> 
>   The original maintenance manuals were written around the inherent 
> limitations of the test equipment available at the time (URM-25's). 
> While I try to keep the filaments glowing and avoid transistor/IC 
> based radios in my setup I do use more modern test equipment.
> 
> 
> 
> ----------------------------------------------------------------------
> --------
> 
> 
>  
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