Older Fisher Goldbug not the GBII

[pavoloc0]

Does anyone know of a place where I can download a schematic/service manual for this detector?

I have a feeling it needs a tune-up since it's been bouncing around in the back of my Jeep.

Best to All -bill

[Eugene52]

Re-Inventing Gold Bug I

Does anyone know of a place where I can download a schematic/service manual for this detector?

I have a feeling it needs a tune-up since it's been bouncing around in the back of my Jeep.

Best to All -bill

Well it has been over one year and It looks like a Gold Bug I schematic never surfaced here on Geotech . Does anyone remember a hand drawn schematic of the Gold Bug I ?? Maybe a "PDF File" from W. Lahr ?? I was reading some other Gold forum last night and as we all know , the Gold Bug II is very impressive . The Gold Bug I "Original Design" has been discontinued a few years and is "no longer in production" !!!! I have not even seen a used Gold Bug I for sale in a while !!

1. Does the Gold Bug I have a PIC Chip or similar controller ?
2. Is a complete Field Test [Depth Result] comparison of both models I & II
posted anywhere ??
3. Search Coil Specs for Gold Bug I ?
4. A Complete and clear PCB Circuit Board photo ??
5. Does it detect coins as deep as the Tesoro Lobo ??
6. If the Gold Bug II is around 71 khz , is Gold Bug I the same ??


I am mostly interested in seeing Gold Bug I information at this time . I know Ivconic did some repair work on a "Gold Bug" a while back so he may have some answers. I know we can proceed on a Gold Bug I project on this forum , I am not interested in the Gold Bug II because it is still in production Any comments or opinions are very welcome ....................Regards........Eugene

[maxbiri]

I must have it samewhere, i will look for it asap.

Bye Max

[Qiaozhi]

This is the only Gold Bug schematic that I have, and I've no idea whether it's version 1 or 2.
Is this what you're looking for?

[Eugene52]

Original Gold Bug I

This is the only Gold Bug schematic that I have, and I've no idea whether it's version 1 or 2.
Is this what you're looking for?

Thank-You Qiaozhi , I am pretty sure It is the gold bug I schematic . The IC chips labeled 404 , are they discontinued ?? And of course it has the world famous Fisher Transformer . I also see this has a 1 k adjust on the 10k side of the transformer must be variable frequency adjust for parallel TX coil ?? and a 19.2 khz crystal !! So maybe it is not 71 khz like the gold bug II !!! I wish someone would post a bunch of good clear photos of the PCB "circuit board" soon ... Thanks again Qiaozhi........Eugene

[Eugene52]

Original Gold Bug

Thank-You Qiaozhi , I am pretty sure It is the gold bug I schematic . The IC chips labeled 404 , are they discontinued ?? And of course it has the world famous Fisher Transformer . I also see this has a 1 k adjust on the 10k side of the transformer must be variable frequency adjust for parallel TX coil ?? and a 19.2 khz crystal !! So maybe it is not 71 khz like the gold bug II !!! I wish someone would post a bunch of good clear photos of the PCB "circuit board" soon ... Thanks again Qiaozhi........Eugene

Here are the only photos I can find , this Gold Bug I in used condition can still fetch $250.00 dollars the stock coil is a 5x10 inch and optional coils were 7x14 inch and 3x6 inch . I see a ground reject adjustment but no external discrimination adjust !!!!! $250.00 dollars , and how old ???.Unbelievable High Resale Value.............Regards.......Eugene/Generic Member/ Stalni-Clan

[maxbiri]

It's the goldbug I,i presume, ir's the same schematic that i have.
If i well remember version I havent discrimination control on panel, maybe disc is preset.

Bye Max

[Eugene52]

Original Gold Bug

I believe this machine has a lot of potential . What is a funny coincidence is the frequency of this Gold Bug I is around 20 khz which is close to the original VLF Tesoro Lobo !!!!! Competition between the two companies in the 1990's ??? And then later Fisher changed the frequency to 71 khz on the newer Tesoro Lobo II , why is that ??? Please correct me if I am wrong , but if some changes are made here , this Gold Bug I can be a hot machine for Coins and Gold !!!!!!!!............Thanks..........Eugene

[porkluvr]

Eugene52, LS404 is from STMicroelectronics. They are available from Mouser. IMO they are very similar to MC33179.

The 1k pot is used for drive level adjustment and should have no effect on frequency. I am guessing that drive level should be set as high as possible while maintianing a 50/50 waves from the phase reference comparators. This would best be set with O'scope to monitor waveforms. Set drive level too high - and the square waves will be square no more. Remember, I'm just guessing.

Maxbiri, The Goldbug does not have discrimination by design. According to the operator's manual, ANY amount of discrimination could cause certain gold targets (especially small nuggets) to go undetected. You may have to dig more trash, but the possible pay-off is deeper detection of more valuable targets!
You can get (most?) Fisher manuals here: http://www.fisherlab.com/hobby/op_mans.htm

I have been trying to analyze the Goldbug circuit, but it has some strange twists that baffle me. There may be some other "errors" (or maybe it's my lack of understanding) but I can't quite digest the circuitry around the CD4053 pin 14. I get nervous trying to figure it out - maybe I should relax and try to believe. I would like to maybe clone GB(1) (except I'd modify the areas that don't want to run in LTspice and what I can't digest).

Qiaozhi, this schematic is definately not the Gold Bug 2. GB2 uses something like 71kHz, and has mineralization adjustments not present in the GB1.

I think the transmit coil should measure around 1mH, but could somebody please measure and post the coil inductance and resistance specs? A properly operating Gold Bug is no small potato!

[Eugene52]

Original Goldbug I

Eugene52, LS404 is from STMicroelectronics. They are available from Mouser. IMO they are very similar to MC33179.

The 1k pot is used for drive level adjustment and should have no effect on frequency. I am guessing that drive level should be set as high as possible while maintianing a 50/50 waves from the phase reference comparators. This would best be set with O'scope to monitor waveforms. Set drive level too high - and the square waves will be square no more. Remember, I'm just guessing.

Maxbiri, The Goldbug does not have discrimination by design. According to the operator's manual, ANY amount of discrimination could cause certain gold targets (especially small nuggets) to go undetected. You may have to dig more trash, but the possible pay-off is deeper detection of more valuable targets!
You can get (most?) Fisher manuals here: http://www.fisherlab.com/hobby/op_mans.htm

I have been trying to analyze the Goldbug circuit, but it has some strange twists that baffle me. There may be some other "errors" (or maybe it's my lack of understanding) but I can't quite digest the circuitry around the CD4053 pin 14. I get nervous trying to figure it out - maybe I should relax and try to believe. I would like to maybe clone GB(1) (except I'd modify the areas that don't want to run in LTspice and what I can't digest).

Qiaozhi, this schematic is definately not the Gold Bug 2. GB2 uses something like 71kHz, and has mineralization adjustments not present in the GB1.

I think the transmit coil should measure around 1mH, but could somebody please measure and post the coil inductance and resistance specs? A properly operating Gold Bug is no small potato!

Thank-You Porkluvr for your post here , I will be off the forum for 6 weeks , Work related , I will respond to all posts here , later !!! Take care everyone !!!!!!!!!!!!Eugene52

[yildiray]

are there pcb?

Hello everyone achievements in this issue to help please

[porkluvr]

Could somebody please take readings for inductance and resistance for the receive coil (19.2kHz original Gold Bug)? Oh, and post the information here.

Thank you, thank you!

[yildiray]

hello friends gold bug are there pcb and assmbly diagram? best regards