AMZ FX ANALOG ALCHEMY GEOFX MEF ROG MEF DIY WIKI

5V Regulator - help please

Started by KRK, February 25, 2006, 08:43:35 AM

Previous topic - Next topic
Print
Go Down Pages1
User actions

KRK

February 25, 2006, 08:43:35 AM
I'm building the Rebote 2 delay from the PCB from tonepad.com. When I bypass I get an audiblr pop and bypassed signal. When the effect is on I get nothing.


Looks like I'm getting 9v across the entire circuit so I think my suspect is the 5V regulator. Three questions:

1. Will 9V fry the PT2399?

2. Am I measuring it correctly the negative lead of my meter on the black wire of the battery clip, red lead placed where I am measuring voltage

3. The 5V regulator is a Motorola 7805 BT - Looking at the data sheet I got from all data sheets I am 99% sure I connected it correctly. If it was backwards would that give me 0V everywhere or 9V everywhere?

Cheers!

R.G.

#1
February 25, 2006, 08:52:11 AM
Quote1. Will 9V fry the PT2399?
Probably. Sorry.

At this point, you have either lost it or not. Go fix the power supply problem, get 5V working correctly, and if it does not work then, replace the 2399.

Quote2. Am I measuring it correctly the negative lead of my meter on the black wire of the battery clip, red lead placed where I am measuring voltage
Yes.

Quote3. The 5V regulator is a Motorola 7805 BT - Looking at the data sheet I got from all data sheets I am 99% sure I connected it correctly. If it was backwards would that give me 0V everywhere or 9V everywhere?
Unknown - it depends on the innards of the IC and how it fails, if it has failed. A better thing to do is to look for a short across the regulator with your DMM set to resistance, and no battery in the clip.
R.G.

In response to the questions in the forum - PCB Layout for Musical Effects is available from The Book Patch. Search "PCB Layout" and it ought to appear.

KRK

#2
February 25, 2006, 09:03:24 AM
Quote from: R.G. on February 25, 2006, 08:52:11 AM
Quote1. Will 9V fry the PT2399?
Probably. Sorry.

At this point, you have either lost it or not. Go fix the power supply problem, get 5V working correctly, and if it does not work then, replace the 2399.

Quote2. Am I measuring it correctly the negative lead of my meter on the black wire of the battery clip, red lead placed where I am measuring voltage
Yes.

Quote3. The 5V regulator is a Motorola 7805 BT - Looking at the data sheet I got from all data sheets I am 99% sure I connected it correctly. If it was backwards would that give me 0V everywhere or 9V everywhere?
Unknown - it depends on the innards of the IC and how it fails, if it has failed. A better thing to do is to look for a short across the regulator with your DMM set to resistance, and no battery in the clip.

Thanks for the response!

The resistance across the 5 v reg hovers around 10 ohms for about 3 sec then I get no resistance
Print
Go Up Pages1
User actions