Blast from the past a Goldscan II

[Paul Harris]

Looked at the fathers Goldscan II after he said it had let off a puff of magic smoke, but it still works. Apart from his Beach Burner he says this was his best machine!!! Anyone know what the function of the black potted box is in the corner?

[Qiaozhi]

Looked at the fathers Goldscan II after he said it had let off a puff of magic smoke, but it still works. Apart from his Beach Burner he says this was his best machine!!! Anyone know what the function of the black potted box is in the corner?

[ATTACH]53846[/ATTACH][ATTACH]53847[/ATTACH][ATTACH]53848[/ATTACH]

It looks to me like it could be an audio output transformer. It appears to be connected to the volume control and the headphone socket.

[waltr]

Audio x-former looks good.

Those caps that are burnt look like Tantalum which do fail shorted.
Maybe just replacing them will get it going again.

[6666]

Looks like a lot of corrosion on that trimmer to,
wonder what took out the tants like that.

[Eddy71]

These are damaged tantalum capacitors. Usually they look like this after applying high voltage.

[Paul Harris]

I'll suggest these caps need changing, any idea as to those two bad caps value?

Here's the other board out of the GS2.

[kt315]

usually tants set on power lines. check by tester the way from tants' pins to batt pads or to voltage converter, if it is.
thx for HR pics. i kept them in a folder 'ERIC FOSTER'.

[profesor]

Hello, does this device have a scheme?
Can you help to extract schema.
Thank you.

[godigit1]

Looks like a lot of corrosion on that trimmer to,
wonder what took out the tants like that.

That,s what I thought too. being that it still works Id check that electroleytic maybe.

[Ferric Toes]

Hi Paul, The two tantalum caps were almost certainly 22uF 16V.

The potted module contained the zeroing circuitry for the two Rx channels. I am trying to locate the circuit diagrams for the GS2, but after all this time and moving from place to place (both workshop and house) it is not easy. However, I have found a folder marked GS2 and will post anything relevant.

Eric.

[Paul Harris]

Hi All, thanks for the replies.

Hello Eric, thanks for the cap values, I will let him know and thank you for any info you could pass on about this great machine. He said he tried the machine with a coil, the depth was still very good, even though he's not used it in 15 years and it has two burnt caps, but it lost the threshold after a short time and he struggled with it until giving up. His GS II needs a bit of TLC from me.

[kt315]

i think the tants were reversed, then yes this cause of the burnt. if you see a line on the tant case it is not NEGATIVE like
you can guess, as always you meeting on electrolitics. this is the POSITIVE pin.
with tants you must be careful.

[Paul Harris]

i think the tants were reversed, then yes this cause of the burnt. if you see a line on the tant case it is not NEGATIVE like
you can guess, as always you meeting on electrolitics. this is the POSITIVE pin.
with tants you must be careful.

I don't know why they burnt, maybe it was just age, he has had that detector since around 1982 and that was his go to machine for many years - its seen a lot of action.

[Ferric Toes]

Here are two schematics of the GS2 Rx board. The earlier 1982 version in which the points that go to the potted module are circled in red. The second schematic drawn a couple of years later is more complete and I have highlighted the potted module within the dashed red lines.



Eric

[kt315]

thx Eric. but his burnt tants on TX board while you shared RX ones.