Problem with surf pi 1.2

[kellogs]

Hi to all i am a new member and have taken up this hobby i live in Australia don't hold hold that against me.I have purchased a couple of silver dogs surf pi 1.2 detectors i don't know what i have done wrong but my coil is getting hot and has 11.1 v as this is my first time at building a pc board could any one help, you all seem to have been doing this for a long time would be so grateful
Kind Regards
Kellogs

[Chet]

Hi kellogs, I assume that you do not have an oscilloscope. So start by taking voltage readings on the three pins of the MOSFET transistor that is connected to the coil. Also note whether the voltages are + or -. Also measure the +5 volt and the -5 volt power outputs referenced to ground. Possible problems that would cause the coil to heat up are that the MOSFET transistor is installed in backwards; the wrong kind of MOSFET is installed (P-channel vs N-channel); the 555 timer circuit is not working correctly or the battery is somehow connected with the wrong polarity. There are different versions of the Surf PI circuit diagram available. To get everyone on the right one please post the diagram that you have with the voltage measurements taken. Also the details on your coil would help. We will get you through this problem.

[ice413]

Hi.
Did you put all the components in the right place? And the right way ?
Do you have any photo of your board ?

[kellogs]

Hi Chet thanks for replying so quickly no i don't have a oscilloscope i will do what you have asked and will reply back it is really good to have people with that are willing to help we have a place called jaycar that sell a lot of components but not helpfull regarding problems have a great day.
Kind Regards
Kellogs

[kellogs]

Hi ice413 i will have to check every thing again you have been realy great i will get back to you later
Kindest Regards
Kellogs