[SixClub] Amplifier Questions...

[KB0NLY]

So far it looks like the finals and the driver are kaput.  I removed them 
and tested with a VOM, shorted from collector to base.

73,

Scott



--------------------------------------------------
From: "Peter Chase" <pdcn1j at msn.com>
Sent: Friday, June 04, 2010 12:35 PM
To: "6meter club" <sixclub at mailman.qth.net>
Subject: Re: [SixClub] Amplifier Questions...

>
> If the input looks OK, then replace the final.  If not then keep checking 
> back until you find something else wrong with the circuit up to the 
> device, Like a voltage thats to high or  to low.  Possibly no voltage ?? 
> something like that.  Sounds like normal stuff that goes wrong with amps. 
> Focus on a defective component .
>
>> From: kb0nly at mchsi.com
>> To: sixclub at mailman.qth.net
>> Date: Fri, 4 Jun 2010 12:21:48 -0500
>> Subject: Re: [SixClub] Amplifier Questions...
>>
>> There is no output...
>>
>> Some more specifics... it's a 10w input 100w output amp. Driving with 10w
>> there is ZERO output. I think the driver, an MRF646 might also be bad.
>>
>> There is no measureable output with even an RF Probe.
>>
>> 73,
>>
>> Scott
>>
>>
>>
>> --------------------------------------------------
>> From: "Peter Chase" <pdcn1j at msn.com>
>> Sent: Friday, June 04, 2010 11:55 AM
>> To: "6meter club" <sixclub at mailman.qth.net>
>> Subject: Re: [SixClub] Amplifier Questions...
>>
>> >
>> > Just check the input to each final and compare it to its output. You
>> > should have a notable increase at the output of each . You should look
>> > up the RF device so you know what to expect for power output and what 
>> > the
>> > normal parameters are. this can be done with basic test equipment. Hope
>> > this helps.
>> >
>> > Regards
>> >
>> > Pete N1JHF
>> >
>> >> From: kb0nly at mchsi.com
>> >> To: sixclub at mailman.qth.net
>> >> Date: Fri, 4 Jun 2010 11:45:27 -0500
>> >> Subject: [SixClub] Amplifier Questions...
>> >>
>> >> I know this is OT, but there is a lot of smart cookies on here and the
>> >> other
>> >> reflectors I have tried, like the AMPS reflector just don't get any
>> >> replies
>> >> like here...
>> >>
>> >> Questions..
>> >>
>> >> 1. I have a UHF amp I'm working on, a RF Concepts 4-110. I think the
>> >> finals are bad, but need someone to verify my bad memory. When testing
>> >> these bipolar transistors the collector-base and base-emitter 
>> >> junctions
>> >> should test as a diode correct? I have a dead short from base to
>> >> collector
>> >> so that seems to verify they are fried. And the emitter-collector has 
>> >> to
>> >> be
>> >> open in both directions, well of course its not because of the dead 
>> >> short
>> >> to
>> >> the base.
>> >>
>> >> 2. It's been a while since I worked on a solid state amp... Whats the
>> >> package type of the small capacitors used on the finals, those little
>> >> square
>> >> metal jobs with a tab out of one side. For the life of me I can't
>> >> remember
>> >> the package number so I can go catalog search for some new ones, as 
>> >> I'm
>> >> sure
>> >> they need replacement after the heating they took on removal. Also, 
>> >> the
>> >> marking on them, in this case 30 and 40, I believe that's in pF 
>> >> correct?
>> >>
>> >> 3. This amp has a bias adjust for each transistor, what is the best 
>> >> way
>> >> to
>> >> adjust the bias after replacing the transistors, just set for minimum
>> >> idle
>> >> current or is there a number I should be shooting for? No specs 
>> >> available
>> >> from RF Concepts unfortunately but I was able to actually find a one 
>> >> page
>> >> schematic at least.
>> >>
>> >> 73,
>> >>
>> >> Scott
>> >>
>> >> ______________________________________________________________
>> >> SixClub mailing list
>> >> Home: http://mailman.qth.net/mailman/listinfo/sixclub
>> >> Help: http://mailman.qth.net/mmfaq.htm
>> >> Post: mailto:SixClub at mailman.qth.net
>> >>
>> >> This list hosted by: http://www.qsl.net
>> >> Please help support this email list: http://www.qsl.net/donate.html
>> >
>> > _________________________________________________________________
>> > Hotmail is redefining busy with tools for the New Busy. Get more from 
>> > your
>> > inbox.
>> > http://www.windowslive.com/campaign/thenewbusy?ocid=PID28326::T:WLMTAGL:ON:WL:en-US:WM_HMP:042010_2
>> > ______________________________________________________________
>> > SixClub mailing list
>> > Home: http://mailman.qth.net/mailman/listinfo/sixclub
>> > Help: http://mailman.qth.net/mmfaq.htm
>> > Post: mailto:SixClub at mailman.qth.net
>> >
>> > This list hosted by: http://www.qsl.net
>> > Please help support this email list: http://www.qsl.net/donate.html
>>
>> ______________________________________________________________
>> SixClub mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/sixclub
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:SixClub at mailman.qth.net
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>
> _________________________________________________________________
> The New Busy is not the old busy. Search, chat and e-mail from your inbox.
> http://www.windowslive.com/campaign/thenewbusy?ocid=PID28326::T:WLMTAGL:ON:WL:en-US:WM_HMP:042010_3
> ______________________________________________________________
> SixClub mailing list
> Home: http://mailman.qth.net/mailman/listinfo/sixclub
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:SixClub at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html