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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