New to the forum

[Coe42]

Hi From Ohio!

Just wanted to say hello and let you know that I have just started building a HH1 (SMT board!) I'll be posting my progress and asking questions if I need some help. I plan to build a waterproof metal detector for scuba diving. Any suggestions will be greatly appreciated!

Thanks!

[Coe42]

Need help!

I built the first part (power supply) and everything went ok, but now I've finished the second phase (clocking) and instead of -5V in the testing points suggested in the article I have -7.6V. Also the output of the 555 varies from 0 to -7.6V. One thing that bothers me is that I re-soldered diode D1 after the first test. Could it be D1 the problem? Did I burn any/any other component?

Thank you!

[authere]

HH1 SMT

Hi Coe 42,
I do hope you keep us informed of your progress as i have the PCB en transit and will be starting from scratch and would enjoy the company while trying to build mine. I hope to gain a better understanding of electronics and gain some building skills while i'm at it.
Good Luck,
Regards Ron

[Coe42]

SMT board

Hi Ron,

If you can still change go for any through hole project, unless you are very good with the soldering iron, have perfect sight and lots of patience. I do not have some of these requirements so I'm still stuck with the -7.6V problem, and I don't want to do anything else until I solve this problem. Hopefully I'll hear from some expert soon, if not I will have to start replacing components, and is something that I really don't want to do. The board is nice and compact but everything is so small and close that makes it difficult to solder one component without desoldering the neighbor.

Anyway, if you have the above qualities, go for it and have fun! I'll be glad if I can help you. And please, keep us informed too!

David

[Altra]

Hello David,

It sounds like you may be taking your voltage readings from the wrong points. On the HH circuit your battery "+" is the ground, not the battery minus. So connect your volt meter to Bat+ and -5v output. The same goes for the 555 (B+ and pin3 output). Hope this helps

mark

[Coe42]

Hi Mark, thanks for your response!

YES! I don't have the board now here with me but I'm using a 9V battery to test and I may have screwed up the battery clips with the battery connector clips and taken the wrong measurement. I'll try again when I get home and I'll let you know.

Thank you very much!!!!

David

[Coe42]

Nothing...

Hi Mark,

Still the same problem . I'll replace D1, since everything was working fine before it came out. I can measure a voltage drop through D2 that decreases with time (probably as C3 discharges) but I cannot get anything through D1... I'm measuring -7.4 on most parts of the circuit.

I'll let you know.

[Coe42]

Got it!

I replaced D1 and Voila! I have the correct voltages! Now I have another problem though... I have -5V on pin 1 of IC11 and 12 but not on IC5.
I'll check after dinner and I'll keep going on!

Thanks!

[Coe42]

Got it working! I'm going for the next phase! I haven't seen any spot for the power LED. Any suggestions?

[Coe42]

Finished the board, questions before test

Hi, I have finished the board (finally!) but I have not attached the coil and test it yet. I have a couple questions I would appreciate if somebody could help before I proceed to test. In my board (SMT Rev C, the one that is in the manual) after putting everything needed I have a few empty spots: R37, C27, Q10, R49, R22, C16, R51 and R52. I have only shorted R22. Do I need to short anything else?
Also I have a 8 Ohm speaker. Will it work? I read somewhere in the forum somebody had a "bad" experience with an 8 ohm speaker.
Thank you!

[Coe42]

Help please!

Hi all! Sorry to post again, but I really need help.

From the schematics I understand that I have to short R51 and R52 (I did). I do not see clear what to do with the rest of resistors-capacitors-transistors not used, and a smt board does not leave a lot of room to start messing up with shorts.

I have everything else set up and I just tested the project to find out that the coil and most of the pots are not doing anything. I can hear a low volume high pitch sound on the speaker that seems to be only affected by R3 (it changes the frequency).

That all I have. I am testing with a regular 9 volt battery.

Is there anywhere where I can test voltages to follow up the circuit with everything on the board?

Thank you!

[Carl-NC]

I assume from post #10 you are using the VCO audio option. So, yes, all those parts should be omitted, except R22 should be shorted. For VCO audio, R51 and R52 should be omitted. You can get zero-ohm SMT resistors to use for shorts.

- Carl

[gold1958]

waterproof housing

Hi Guys

the first posting in this thread asked about a housing for underwater. I have built and used the HH while scuba diving and it works really well provided that you set it up for operating in water. If you want I can post a picture or two.

[Coe42]

Hi! Thanks Carl and Gold!

Carl, Sorry... yes, is the VCO option. Now I have the shorts as you said but nothing seems to work except pots 2 and 3 that change the audio freq.

Gold, yes please, I really would like to see the pics! Is it the SMT version? If so, can you please also post a pic of the board?

Thank you!!

David

[authere]

HH1 SMT

Hi All,
Finally recieved my PCB's, thanks Carl!!, now the fun begins
Ron