Help with mini pulse please.

[bigted]

I have started building mini pulse. Every thing worked fine till I got to step 6. I measured the voltages again and minus is still at 5v but the positive is a lot lower. Any ideas please.

[CAS]

DoUble check all the values of components you soldered in the last step. Also make sure you haven't bridged between any of the pads on the ic's

[bigted]

Thanks for the reply. I fixed the problem. Ic was in the wrong way. Have you built a mini pulse?

[bigted]

Also I can't hear the buzzing noise now when you put coil next to headphones?

[CAS]

Have you checked all the pulses at the test points as per the instructions with an oscilloscope? Go back through each step doing the measurements and see where things arent as they are supposed to be.

I built mine a while ago but still use it to test ideas for a new project I am working on.

[bigted]

Yes followed instructions as per document. I don't have a scope, using a multimeter. I'm up to the bit with the can and the coin testing tp3, but it seems my coil doesn't work now.

[CAS]

Did you replace the ic you had in backwards? If not, it may have been damaged.

[Qiaozhi]

Yes followed instructions as per document. I don't have a scope, using a multimeter. I'm up to the bit with the can and the coin testing tp3, but it seems my coil doesn't work now.

I would suggest the following course of action:
1. Recheck the _5V and -5V supplies are ok. If not, then fix as appropriate.
2. Connect a speaker between TP1 and TP10, and listen for a high-pitched tone (~1kHz). If there is no tone, then the TX oscillator is kaput.

[bigted]

Thanks. Will check when I get home.

[bigted]

I can hear a tone. Here is pic of the board so far.

[bigted]

All is good now. One of the coil wires attached to the PCB wasn't connecting proper. I can guarantee I will be back for more help. Thanks for the help so far...

[Tibuck19]

Answer my own question lol