Lil Amp Repair Help Please

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pede69
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Posts: 2
Joined: Sunday 11th Mar 2012, 11:35
First Name: John
Location: Daytona Beach

Lil Amp Repair Help Please

Post by pede69 » Thursday 12th Apr 2012, 13:02

Pics for this help request and topic are here:
http://daytonacb.com/amp-prob/

Original problem:

With amp on and receive amp off, amp worked OK.
With amp on and receive on, no increase in receive performance.

Took amp to a tech type person I know and he said that the problem
was the 2N3906 to the left of the relay on the left, looking from the
front. Said it was the receive pre-amp transistor.

Here's where it gets odd...

I purchased some 3906's from RS and replaced two. One on each
side of each relay.

Now, when hooked up and amp is off, radio receives as normal. Turn
amp on and relays click instantly and receive shuts down. Well... If I
turn radio volume all the way up, I can hear a small bit of radio sound.

Hm... I looked at my work and said... crap, I put the TO-92s in backwards.
So... I busted out two new 3906s and installed them opposite of the way I
installed the first two.

Damnedest thing... amp does the same exact thing no matter which
way the transistors are installed.

Amp on, no sound. Amp off, full radio receive sound.

Relay points are closing as soon as power is applied through power on switch.

OK everyone... What the heck is going on here and how do I make this
amp right?

Oh... I wish I had a schematic but I don't.

Thank you all for your kind help,
John

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