SD 2100

[downhalo]

Anyone got any info on modding up the old Green box 2100 machines?

Love to see some DIY stuff.

[Finderskeepers]

Build Mario's dds signal generator, works really well on my sd2000. It's well documented how about connecting it to the 2100v2, but as yours is an earlier 2100 I think the circuitry is slightly different.

[downhalo]

Yeah not the same machine unfortunately... plus its a big extra box to carry around...

[downhalo]

Found some simple mods that improve sensitivity and depth
Just remove 2 1nF caps, short one, replace the other with a 180 or 220pF cap for sensitivity, or connect 3 in parallel with a 3 position toggle, to switch in and out capacitance.

img below

[downhalo]

switched out the 560 to a 5nF.. depth is better..

[downhalo]

Okay final setup, 180pF base, switch in, 330pF and 860pF.. gives best results on super fine, and at max depth..

[detectormods]

You can go further with the C values but you will run out of GB adjustment on Channel 2 , but you can change the scaling resistors to get extra range.

[downhalo]

Nah, think I'll stick with it as is.. performance is sweet... thought it gives a bit of a scream when switching back to 180pF...

[detectormods]

It will do that when some of the coil ringing starts getting into the receiver, try extra damping.

[downhalo]

Okay, cool. so how would i go about doing that?

[detectormods]

Hook up a coil and change the value of the 390 0hm damper resistor or bank of resistors that = 390 ohms (depends on detector) observe coil ringing on a cro, observe the results, do not kill any target signals by squashing it down too much.