DBX 3BX question

Rob41 · 5th February 2011, 11:45 PM

Hi all,
I'm pretty much a lurker here because the members knowledge is almost always above my head. Hopefully next summer I'll get a couple projects off the ground and actually be able to contribute to this wonderful site.

I've got a non-functioning first gen DBX 3BX that when you turn it on (source going through or not) all of the indicator lights remain on and none of the controls have any effect. Accept the power button of course. I've used De-oxit cleaner and lube on all the switches and sliders and still nothing.

The only thing I could find wrong inside is a bad tip33 transistor which I already got a replacement for from Digikey and will install Monday. I checked all the caps and diodes and resistors and found nothing else wrong. I also looked at the traces but could see no cracks or damage. Keep in mind, although I'm a merchant marine engineer, My knowledge of circuit boards is limited.

I guess I'm wanting some opinions from the experts here. Could it just be a single transistor (the tip33) that's the sole cause of the problem, or is it likely that there are other issues?

Here is a picture of the burned tip33:

Thanks for the help,
Rob

Rob41 · 8th February 2011, 04:14 PM

Sorry, if I posted this question in the wrong heading would a moderator please put it in the correct spot?

5th February 2011, 11:45 PM	#1
Rob41 diyAudio Member Join Date: Dec 2010 Location: Northern Michigan	DBX 3BX question Hi all, I'm pretty much a lurker here because the members knowledge is almost always above my head. Hopefully next summer I'll get a couple projects off the ground and actually be able to contribute to this wonderful site. I've got a non-functioning first gen DBX 3BX that when you turn it on (source going through or not) all of the indicator lights remain on and none of the controls have any effect. Accept the power button of course. I've used De-oxit cleaner and lube on all the switches and sliders and still nothing. The only thing I could find wrong inside is a bad tip33 transistor which I already got a replacement for from Digikey and will install Monday. I checked all the caps and diodes and resistors and found nothing else wrong. I also looked at the traces but could see no cracks or damage. Keep in mind, although I'm a merchant marine engineer, My knowledge of circuit boards is limited. I guess I'm wanting some opinions from the experts here. Could it just be a single transistor (the tip33) that's the sole cause of the problem, or is it likely that there are other issues? Here is a picture of the burned tip33: Thanks for the help, Rob

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8th February 2011, 04:14 PM	#2
Rob41 diyAudio Member Join Date: Dec 2010 Location: Northern Michigan	Sorry, if I posted this question in the wrong heading would a moderator please put it in the correct spot?

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