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Question about 15W amplifer

 
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Question about 15W amplifer
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bannbann
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Joined: 28 Sep 2004
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Post Question about 15W amplifer Reply with quote
After few weeks excelent operation, power transistor melts itself out of the solderings in board and does not work anymore. After resoldering it works again and no such problems, is it thermal design problem?

Second question, power is low at lower frequencies 87,5 - 88,5. What i should do ?
Tue Oct 05, 2004 3:41 pm View user's profile Send private message
pcs
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Post Reply with quote
We are now equipping those amplifiers with a small fan, they did
run a little hot before, yes.

So do use a small fan to blow across the output transistor.

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Tue Oct 05, 2004 6:17 pm View user's profile Send private message Visit poster's website
Sir Nigel
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Post Reply with quote
Good thing this hasn't happened to my 15w booster!

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Wed Oct 06, 2004 12:19 am View user's profile Send private message Visit poster's website
pcs
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Post Reply with quote
It won't unless you really push it.

But still, a small PC style fan is welcome!

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Marko - PCS Electronics
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Wed Oct 06, 2004 12:59 am View user's profile Send private message Visit poster's website
bannbann
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Post Reply with quote
Before complete brurndown, SWR circuit protects the transistor and turns power off Actually what is the type that transistor ?


Ok, but my second question was: how to boost lower frequencies, my quick hack was to pull coils.
Fri Oct 08, 2004 4:20 pm View user's profile Send private message
Mustang7172
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Post Smokin while broadcasting Reply with quote
I have a 15 watt booster, I had to resolder the power supply joints, due to heat, a month later, my booster went into complete disaster. It smoked real good, and Powersupply no longer works. I even had 2 fans on mine.
Fri Dec 17, 2004 10:32 am View user's profile Send private message
pcs
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Post Reply with quote
We were selling these units with built-in mains power supply only
in the very beginning, but it soon turned out that the transformers,
even though according to specifications good enough, were in fact
not suitable so we decided to use external power supply months
ago.

Boosters are now equipped with optional external power supply
or powered from other 12-15V DC power supply so this problem
was eliminated.

Additionally, they now have a fan above the output rf tranzistor
so things are cool.

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Best regards,
Marko - PCS Electronics
--------------------------------------------------------
Turn your PC into a FM radio station!
http://www.pcs-electronics.com
fax +386 4 2316 128
Fri Dec 17, 2004 3:43 pm View user's profile Send private message Visit poster's website
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