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Bayou Jumper troubleshooting audio chip

Jim, N5IB
 

Hi Bryan,

Did you get my earlier message?

Those voltages, and the hot condition tell the tale.
I'm pretty sure U1's output is being shorted to ground somewhere. It may possibly have survived, but is most likely done for.
What kind of speaker of headphones are plugged into the jack?

Jim, N5IB
bryan rice
 

Stereo type like ear buds i went back through this morning with the build sheet all parts are in there rite place i did this 3 times just to triple check my self i dont know why u1 is showing low voltages. If i ordered a nother audio chip how wolud i do that with out buying the whole kit again. 



On Thu, Jan 28, 2021, 12:03 PM Jim, N5IB <n5ib@...> wrote:
Hi Bryan,

Did you get my earlier message?

Those voltages, and the hot condition tell the tale.
I'm pretty sure U1's output is being shorted to ground somewhere. It may possibly have survived, but is most likely done for.
What kind of speaker of headphones are plugged into the jack?

Jim, N5IB
Jim, N5IB
 

Get in touch with Steve the Kitter ... his email contact info is at the bottom of the kit web page.
He'll be able to set you up with a replacement chip.

In the meantime, do you have a way to measure the supply current being drawn by the radio?

If so, unplug your earbuds, turn the radio to receive mode and look at the supply current . It should show a brief high current spike for a second or two as capacitors are charging up, then drop back to a steady 25 mA or so.
If it stays above say, 30 mA after 3 or 4 seconds, then turn the radio off. Pop U1 out of its socket and repeat the current test.

Report back what you discover.

Jim, N5IB
bryan rice
 

With the chip out the voltage stayed above 30ma soon as put  the chip in starts getting warm then the  the numbers are crazy.
Jim, N5IB
 

If the current was about 30 mA without the chip, that's about right.
But you said stayed **above 30 mA** How much above? 40 or 50 mA would be a problem.
What's your power supply voltage? If it's a 13.8 V supply the current will be only a few mA more than what I measured with a 12 V supply.

All indications point to a zapped U1, so go ahead and contact Steve the Kitter for a replacement.
His email contact info is at the bottom of the Bayou Jumper kit page.

While you are waiting for that you can go ahead and check out the transmitter section. It's completely independent of the receiver.

Jim, N5IB
bryan rice
 

My supply is 12 volts ill try to get in touch with him thanks for all the help.73 KG4GCX agent 049


On Thu, Jan 28, 2021, 6:11 PM Jim, N5IB <n5ib@...> wrote:
If the current was about 30 mA without the chip, that's about right.
But you said stayed **above 30 mA**   How much above? 40 or 50 mA would be a problem.
What's your power supply voltage? If it's a 13.8 V supply the current will be only a few mA more than what I measured with a 12 V supply.

All indications point to a zapped U1, so go ahead and contact Steve the Kitter for a replacement.
His email contact info is at the bottom of the Bayou Jumper kit page.

While you are waiting for that you can go ahead and check out the transmitter section. It's completely independent of the receiver.

Jim, N5IB
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