[Amps] For any technicians

[Bill Fuqua]

does the crystal have a capacitor associated with it for adjusting it's 
frequency?
If so the frequency may be determined by the parallel resonant mode of the 
crystal and determined by
the loading capacitance. It may be adjustable over more than a kHz range.

Bill


At 04:18 PM 1/12/2005 -0500, Will Matney wrote:
>I received an original copy of a manual for a Conar model 282 RF signal 
>generator with some other test equipment I bought. I had to tell this even 
>though it doesn't concern amps in particular. The manual included two 
>engineering change notices in it. Now if any has serviced test equipment 
>like me, you'll know that for most old equipment there's no manulas for, 
>and you replace what's bad by the part number or codes. First off, the 
>generator in mention was a cross between two. It stated as follows;
>
>"Your model 282 signal generator incorporates design changes that improve 
>its serviceability and make it easier to adjust. The manual reflects these 
>changes and is marked model 282; however, the front panel is labeled model 
>281. This is correct because no external changes have been made. If you 
>have any questions or need technical assistance, please let us know that 
>you have the model 282".
>
>Now to me, this sounds like they were getting rid of any left over 
>cabinets before a model change. If a serviceman didn't know this, he would 
>be asking for parts and service on a 281! Next, there was a paper called 
>"special instructions" which stated;
>
>"Crystal CR30 Marking; You may find that crystal CR30 is marked 
>incorrectly as 6.5546 MHz. The manufacturer made this error during the 
>marking process. The actual value of the crystal is 6.5536 MHz and can be 
>used in this instrument".
>
>Now what if someone replced the crystal with the marked value and never 
>could get the rf output correct? I would think any manufacturer would have 
>made the crystal supplier re-do the whole lot! The reason I'm mentioning 
>this is I wonder just how many other manufacturers have been guilty of 
>this? Has anyone heard of anyone else doing the same on kits or 
>manufactured equipment?
>
>Will
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