[TenTec] Omni 7 shuts down on overcurrent on 10-12 meters only

[Bob McGraw - K4TAX]

OK are we to presume all other bands operate normally with 90 to 105 watts 
output and that no over-current conditions are present.  Will it operate 
normally when TUNE is activated in any of the modes?  This should produce 
about 15 to 20 watts output.  What happens on 6M when connected to a 50 ohm 
resistive load?

My suspicion is that either the over-current circuit is faulting to which I 
would expect it to be seen on all bands or there is some unique instability 
in the PA more likely due to a capacitor failure.

If all other bands operate normally and TUNE operates normally and the issue 
exists only on 12M & 10M, I wonder what the output power appears to be just 
before shut-down.  I would expect it to go very high and very suddenly.  I 
know the protection circuit is fast so you might try setting the PWR to 20 
watts, activate TUNE in CW mode and work up to the point of shut-down.  If 
the output power suddenly jumps high just before shut-down then there is 
reasonably solid evidence of a PA issue.  All references to power output 
should be done using an external power meter.

A few more details and specifics and I can likely point you to the cause of 
the fault or more likely the specific component.

73
Bob, K4TAX


----- Original Message ----- 
From: "denton" <denton at oregontrail.net>
To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>
Sent: Tuesday, September 25, 2012 4:00 PM
Subject: [TenTec] Omni 7 shuts down on overcurrent on 10-12 meters only


>I have an Omni 7 that shuts down due to over current into a flat 
>load...regardless of power output setting on 12 and 10 meters only. All 
>other bands behave themselves.
> If I even tap the mic it will shut down...
> Called TT about it over a year ago and they think it is either a diode or 
> relay...hate to sent it in.
> Anyone else experience the same?
> Talked to another ham at the Spokane hamfest this last Saturday and he 
> said he had the same problem, sent it to TT for fixing but can't recall 
> just what they did.
> --------------------------------------------------
> From: "shristov" <shristov at ptt.rs>
> Sent: Tuesday, September 25, 2012 10:44 AM
> To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>
> Subject: Re: [TenTec] Balancing Orion 565 VFO knobs
>
>>
>> Michael Cheponis <Michael at Cheponis.Com> wrote:
>>
>>> I have a 566, and the knobs are perfectly balanced.
>>
>>
>> It's great to know that knobs on 566 do not drift by themselves.
>>
>> I managed today to balance both of my 565 VFO knobs.
>> It was easier than expected, took me 15 minutes per knob.
>>
>> Using an 8 mm slot drill, I cut out a ~2 mm deep hole,
>> on the bottom of the cast balancing hole,
>> just opposite of the fastening screw.
>>
>> Quantity of material removed was very similar on both knobs:
>> approximately 100 mm^3, which is ~0.27 g of aluminium.
>>
>> For the record:
>>  the knob itself is ~165 g
>>  skirt (made of metalized plastics) is ~8 g
>>  spring is ~1 g
>>  rubber is ~10 g
>>
>> I completely ignored the skirt and the rubber
>> as being much lighter than the main knob part.
>>
>> Now I can use a much lighter drag, similar to FT1000,
>> and VFO knobs are much more pleasant to use.
>>
>>
>> 73,
>>
>> Sinisa YT1NT, VE3EA
>> _______________________________________________
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>> TenTec at contesting.com
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>>
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