Analogue-sequencer

Hi Fred,

> it works fine... it's just that on the 10A input, i can't measure 
voltage.

OK, it sounds like your meter has three inputs: a common, or ground; 
a Voltage/resistance/mA; and a High current 10A input. When you 
connect the probes to the common and 10A input, this can only measure 
current going through a circuit, it cannot as you say, measure 
voltage.

What you need to do is connect the meter probes to the common and the 
V/Ohm/mA input and set the meter to measure *voltage* not current. 
Now apply voltage to the dc input jack of the P3 and measure the 
voltage between the 2 input pins. It should measure about 9V. If 
that's OK, then put your +ve probe on the anode of D6 (the end 
without the stripe), and the -ve probe on 0V. This should also 
measure about +9V. If you move the +ve probe to the striped end of 
D6, this should be about +8.3V.

Now measure the output pin 3 of the voltage regulator 7805 (you can 
measure this at the striped end of D1 if you have used it). This 
should be +5V. If this all checks out, then chances are the power 
supply is OK.....but......

If the voltage regulator is getting really hot, and you have mounted 
it on a heatsink, then it seems that your circuit is pulling too much 
current. With the circuit running properly, you should be able to 
hold your finger on the regulator without burning it.

Check the orientation of the Zener diode D1 if you have used it (i.e. 
make sure you have put it in the right way round). If it's the wrong 
way round, this will cause a near short of the voltage regulator, and 
cause it to get hot.

Let us know how you get on

All the best

Andy
---

Andy Wilson
http://www.techman.synth.net
andy@techman.synth.net