HH RevC1 help with power supply

[petere]

Hi
I have built the HH in stages as per instructions and everything seemed to be working fine. Had the correct waveforms from TP1, TP6 & 7. Audio working and was going through the process of adjustments with a commercial coil connected, (nuggetfinder brand) seemed to be going well but was concerned I might be picking up to much interference from my work area, so connected a figure 8 looped coil bundle which only measured around 190 uH inductance. I think maybe this is where I went wrong. When I reconnected the NF coil nothing was happening and noticed my +5v & -5v were gone from ic2, 3 & 4. and the 7660 is running quite hot. Have tried replacing ic1 & ic2 with no change. I like to try and figure stuff out as much as I can but concerned I might cause more damage. Not sure where to go now, my knowledge of electronics is limited. Any suggestions on how to troubleshoot will be appreciated.
Thanks

[petere]

Okay I pulled all of the power supply components off the board and found the voltage regulators to be faulty. Replaced IC2, 3 & 4 and both diodes. Caps were OK.
Now I am back up and running, just need to get the adjustments right.
Am able to detect a small nugget at about 1 cm, hope to be able to improve on that though.

[Qiaozhi]

Okay I pulled all of the power supply components off the board and found the voltage regulators to be faulty. Replaced IC2, 3 & 4 and both diodes. Caps were OK.
Now I am back up and running, just need to get the adjustments right.
Am able to detect a small nugget at about 1 cm, hope to be able to improve on that though.

Change the preamp from a single to a dual stage. Have a look at the Minipulse Plus for an example.

[petere]

I plan on looking at the preamp as soon as I get this board running more stable.