[TenTec] Omni VI Logic Board

[Bob McGraw K4TAX]

In reference to my earlier post......the RESET function on the 
microprocessor is a combination of R16 {100K} and C58 {1.0uF} on pin #1 
to ground of U7.   I suggest replacing C58 with a new one and increasing 
the value to 2.2 uF.

My earlier comment was from my recall of another model.   Now I have the 
manual/schematic at my desk.   Sorry for the error.

73

Bob, K4TAX


On 8/27/2020 10:52 AM, Bob McGraw wrote:
> There is a RC timing circuit on the microprocessor RESET line. It is 
> common for the value of the C electrolytic to decrease with age. Thus 
> the original RC time constant value has changed.  That can be the 
> cause of the MP "not coming to life".    Change the C to a new cap, 
> typically 4.4 uF.   I prefer to use a Tantalum type cap.
>
> Also, take time to clean all of the cable connectors, male and female 
> pins.   Use a Q-Tip cotton swab moistened with contact cleaner.   
> Scrub the male pins and then exercise them on the female pins.
>
> NEVER SPRAY ANYTHING INTO THE RADIO
>
> 73
>
> Bob, K4TAX
>
>  On 8/27/2020 9:30 AM, Malcolm McLeman wrote:
>> My Omni VI audio doesn't spark into life for quite a considerable 
>> time and when it does it is usually preceded by unusual old-fashioned 
>> style "motor-boating" noise.
>> Have read the problem is Z3 zener diode on the logic board.
>> Has anyone had/resolved this problem by changing Z3?
>>
>> 73
>>
>> Malcolm F5VBU
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>