My Bandido UmaxII SMD

Thought I'd share my Bandido project.

I had tonnes of fun with it, building out my own circuit from scratch for SMD, ok, copied from pictures of other peeps hard work that deserves the credit.
Learnt to make my own rosin from some hardened park pine gum, that was a good idea for my first attemt soldering SMD's.
Learnt tonnes on op-amps and every chip used, this really opened up my world a little to electronics. This was my second attempt as a beginner so it made me spend hours looking at everything. My first was on breadboard and it just became a nightmare figuring out what went wrong.
Decorated it with some old finds, and tried some nickel plating.

Ended up getting one of those cheap hantek usb oscilloscopes because of it. No regrets.

Some trivia.. Umax is maximum integrated or MAXIM's flagship chip when this detector started using the 4066. They offer better quality pin for pin replacements for these these days, the MAX6420 I think. Weather it will make a difference I don't know but it might be a good option to keep in mind with your next design.

The circuit was from Carl's schematic. I think however the battery light part was horrible. The zener would get so hot it would de-melt itself. It's actually a short if you look at it. Dropped it from the final. I was surprized to get everything working.. I did not expect the detector to sort of disk out lower end iron by default and thought it was a problem having owned some modern detectors it took a while to realise that was a standard modus opperandi upgrade in earlier models. So it's scratchy on steel with no disk, it can crank up to disk out everything, I get a clear positive-negative balance response so I'm happy every time I see it.

When I pot the coil, I'll rather test it with a silver ring than worrying too much about nulling as it seems it's a bit touchy on silver.

Oh.. I stripped some old TV antennae coax we use in our country to find readily available shielding foil tape and taped it up with some fine strands to distribute some conductivity. Seems OK.

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