[TenTec] 229A SWR Circuit - UPDATE

Carl Moreschi n4py2 at earthlink.net
Sun Jul 1 10:04:09 PDT 2012


Also, I believe most diodes in watt meters are germanium.  If they ever 
failed and were replaced with silicon diodes, that can mess up 
calibration badly.

Carl Moreschi N4PY
121 Little Bell Dr.
Hays, NC 28635
www.n4py.com

On 7/1/2012 12:44 PM, Rick W wrote:
> I hung my DVM off the 200uA meter plug and it is completely within specs.  Fully adjustable and it seems to be working.  So it looks like the Korean made 229A meter has failed.
>
> I'll have to do some thinking on a replacement.
>
> Thanks for the bandwidth.
>
>
> 73,
> Rick
> VE7TK
>
>
> Website:  http://www.ve7tk.com
>
>
>> ________________________________
>> From: Rick W<ve7tk at yahoo.ca>
>> To: Ten-Tec Reflector<tentec at contesting.com>
>> Sent: Sunday, July 1, 2012 8:39:29 AM
>> Subject: 229A SWR Circuit
>>
>>
>> I have recently acquired a 229A tuner.  It needed a few repairs - mainly mechanical - but otherwise seems in good shape.  I've replaced the dial elastic cord and it tunes smoothly and consistently.
>>
>>
>> I am having a problem with the SWR / Power measurement circuitry.  I can't get the meter to full scale and power measurements are way off.  Calibration is impossible.
>>
>>
>> The meter is moving - albeit nowhere near the correct deflection.
>>
>>
>> My guess is that the SWR circuit in the 229A is similar to the current 238.  Is there any history of problems with this circuit.  Any reports of:
>> 	1. meter movement failure;
>> 	2. leaky capacitors; or
>> 	3. open or out of tolerence resistors?
>>   This is a pretty simple circuit and virtually all the parts (less the meter) are likely in my junk box. If there's a history of a part failure I'd like to start there.
>>
>>
>> Thanks.
>>
>>
>> 73,
>> Rick
>> VE7TK
>>
>>
>> Website:  http://www.ve7tk.com
>>
>>
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