surf pi 1.2 beeping issue (well not working)

[kaiseredge]

I recently just finished the surf pi 1.2 and turned it on, all it is doing is beeping every 3 seconds from the buzzer, It is not detecting metal. - I checked all soldering and checked all components before putting them in the pcb - I have replaced the chips multiple times also but still have the same issue. I can hear a steady hum from the coil with headphones next to it everything looks good but I'm unsure of what to do from here. maybe the chips are wrong friend of mine gave me the parts for the pcb?

u1 ne555
u2 ne5534p
u3 lm358n
u4 cd4093 ic schmitt trigger
u5 78L05 +5 volts 100ma voltage regulator
u6 ICL7660 cmos voltage ic
u7 cd4066 quad bilateral switch

aside from the pots working I'm not sure what is wrong at the moment.

I would post a picture but it doesn't look any different than the hundreds of pictures on here of the surf pi 1.2

thanks for any help or ideas on what I can try.

[silverdog]

start with supply voltages - look anbd the schematic and check you have +5v and -5v supplys working

[kaiseredge]

I did as you said the voltage seems to be fine 4.92, however when I poked pin 6 of the ICL7660 I get 1.54 volts and the detector works as soon as I poke that pin, if I leave a piece of metal touching pin 6 the detector works great so I'm happy that it is working just confused on why it is thanks for the reply/help

[Tepco]

Clean the board with some good solvent first.

[kaiseredge]

I've cleaned it up very well cleaned it 3x to be sure that wasn't the case - still thanks for the input I'll check a fourth time can't hurt

[porkluvr]

I did as you said the voltage seems to be fine 4.92, however when I poked pin 6 of the ICL7660 I get 1.54 volts and the detector works as soon as I poke that pin, if I leave a piece of metal touching pin 6 the detector works great so I'm happy that it is working just confused on why it is thanks for the reply/help

Did you understand Silverdog's reply? He mentioned two separate voltages, +5V and -5V.

You replied by stating that "the voltage seems to be fine 4.92".
That is great for the +5 volts supply, but what about the -5V supply? Is the negative voltage good?

Do not touch the ICL7660 to answer that question, instead look for -5V by probing LM358 pin-4.

[kaiseredge]

I meant to post it but yes 4.92 and -4.61 I did not leave it out intentionally thanks for the post now it's out there

[skylly]

Your issue is similar to mine.
Have you tune the offset trimmer to let pin 6 of ne5534 to about 0V?