Re: uBITX - U1 Getting Fried - possible cause #ubitx

Vince Vielhaber
 

Something doesn't seem right here. At least one person said that the IC smoked as well as R75. R75 is a 2.2 Ohm resistor connected between pin 6 and ground. Pin 6 is the + input on amp #2.

Vince.

On 03/02/2018 12:20 AM, Jerry Gaffke via Groups.Io wrote:
That might help here, though I'm not sure we fully understand the
problem yet.

This resistor would charge up the 470uF cap at power up, so plugging in
a short
or headphones or whatever at a later time would not be so disruptive.
Is that what you have in mind?

Resistor could be 100 ohms, and still charge the cap plenty fast.
And if 100 ohms, could be there at all times in parallel with the
headphones,
so no need for the fancy speaker jack with the switching contacts.

Jerry, KE7ER

On Thu, Mar 1, 2018 at 09:02 pm, RCC WB5YYM wrote:

Could a person add an 8ohm resistor across the speaker jack on the
NC pin? When you plug in the speaker it would open up that load and
the amp would see the speaker.

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