Author Topic: R104 Smoking When Pressing "IN"

May 21, 2023, 08:48:30 PM
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TheFancyWolf

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Hello!

I am in the setup phase of the CP4500. I am following this guide here. Steps 1-5 went off without a hitch and I am getting the correct power voltages from Step 5.

In Step 6, I send a sine wave, I am able to calibrate it to 2VAC and then I press the IN switch. As soon as I do R104 starts smoking and is done for.

I am using a Bento 8 Pro, so before I noticed the smoke, I am able to hear the sine wave on the output in bypass and insert, the sound itself doesn't change as I manipulate the controls, but the meter was responding correctly to lowering the threshold and adjusting the ratio, etc. But none of the settings affect the actual sine wave. After I noticed the smoke, they no longer respond.

I thought maybe a bad resistor, so I replaced with another 1/4w 220R and the same thing occurred.

Attached is a picture of the board.

My next steps are to re-check the voltages and go through the In Case Your CP4500 doesn't work readings. I didn't see any other similar topics, so apologies if this is covered somewhere else.

I don't get much time to work on this so I thought I would reach out in case anyone had any suggestions for the next time I am able to work on it and hit the ground running.

Thanks!



« Last Edit: May 21, 2023, 08:53:26 PM by TheFancyWolf »

May 26, 2023, 04:49:15 PM
Reply #1

JPK

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Your D19 is in the wrong direction.
JPK

May 28, 2023, 03:27:19 AM
Reply #2

TheFancyWolf

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Your D19 is in the wrong direction.

Yeeeaaahhh.... not a great part to get wrong. I replaced the 104 and switched the diode around and now we appear to be smokeless and the controls are responding to initial tests. Hopefully I didn't mess up any other parts, but it seems like the protection resistor did it's job and sacrificed itself for the cause.

Thanks!