I need help with idx pro silverdog red pcb!!

[Koala]

The TGSL is better on low conductive (short TC) targets like nickles and the IDX is better on higher conductive (long TC) targets like silver coins. This is due to the operating frequencies use in these two detectors. Lower freq better for long TC and higher freq better for short TC.
Dbowers did a comparison of these two detectors on different target in his 'test garden'.

I have several coils for

IDX
Bandido
F1265X

the Fisher out preform the other two on all targets the rest of the machine makes more of a difference than the frequency

the Bandido and IDX can be made to run identical. But with real in the field settings the Bandido out preforms the IDX due to the better discrimination.

[kt315]

No its not as i was getting close to 42 to 45 cm before this malfunction started
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sorry, but you have to add if mention the depth in WHAT mode you get this - ALL METALL MODE or DISC MODE.
sure misunderstanding what you write about.

[Tibuck19]

No its not as i was getting close to 42 to 45 cm before this malfunction started
---
sorry, but you have to add if mention the depth in WHAT mode you get this - ALL METALL MODE or DISC MODE.
sure misunderstanding what you write about.

for starters unless i'm mistaken which is very possible, the IDX red board does not have an all metal or disc mode, it has a normal beep detection mode and a Point point mode which is an audible threshold hummmm, the only way to get a metal mode as you might think of it, is to turn the Disc pot down to 0, in anycase, i was getting the 42- 45 in beep mode with disc pot halfway just before losing the nickels. hope that what you needed to know.

[Tibuck19]

Good morning everyone, Here an update of what had been done and what is going on, as i mentioned, Replacing every poly cap and ic on the board and redoing all of the connections wiring... here are some of the results, With a homemade coil that don made and the F deepscan coil things are looking up as im now closer to 40 cm airtest on most coin from a penny to a quarter with gb pot at around 8k ish, However with both 6b coils the 8 inch( WHICH ALWAYS WORKED ON THIS IDX) and 15 inch it is a whole different story, no progress has been made, the ground balance pot is closer to 21K which means more amplitude on the TX side which seems to cause a step ladder effect on sine wave of RX when i probe pin 7 of the 5534 with a much much lower tx to rx aspect ratio, i will snap a few photos of the oscope later on to show you all what i mean, however with all four coils, there seems to be a shift in pot values, where before the pinpoint audible threshold was around 1/4 turn it is now at a little over halfway, the discrimination for a nickel which use to be at halfway is now 3/4 of the way on the Pot, Also if i am not mistaken, doesn't the TX and RX need to be out of phase with each other? when i probe the tx coming out of pin 7 of U8(lm393) on channel one, and pin 7 of U1 (ne5534) on channel 2, the are both aligned with each other besides an amplitude difference.

[waltr]

Also if i am not mistaken, doesn't the TX and RX need to be out of phase with each other? when i probe the tx coming out of pin 7 of U8(lm393) on channel one, and pin 7 of U1 (ne5534) on channel 2, the are both aligned with each other besides an amplitude difference.

This sounds like the 'resonant' of either the TX or RX coil/circuit is not what it used to be.
I know you said you replaced every poly cap but are the caps for TX or TX resonance good values?

Maybe try adding a cap across the RX cap while watching the signals on the scope.

[Tibuck19]

This sounds like the 'resonant' of either the TX or RX coil/circuit is not what it used to be.
I know you said you replaced every poly cap but are the caps for TX or TX resonance good values?

Maybe try adding a cap across the RX cap while watching the signals on the scope.

The Caps that have been replace are the values on the silk screening, i bought a bunch of the them ( i have enough Caps to populate 3 boards if need be haha) and measured every single ones value between a few of them to get one that is the closest to what the silk screen is showing, is that what you meant? IDK Waltr, for everything to have shifted so much there has to be a resistance change somewhere along the board right? now checking each and every resistor out of circuit seems more time consuming that it is worth, Something somewhere changed big time, What i find odd is everyone tends to think that the 6b coils should not work with the idx, but i have used a 6b coil for almost two years without an issue and all of sudden they no longer work right, i just find it really odd that i was either able to get it to work out of dumb luck or idk what lol. i know the TGSL has a very noticeable phase shift, should the idx be the same? i will pull out the 680p cap and try to find something else with a lower and higher value to see if it changes anything,but again its what was in there while the 6b coil was working perfectly.

[Tibuck19]

Just to correct myself when i said " step ladder effect on sine wave of RX when i probe pin 7 of the 5534" i meant pin 6 of U1 sorry for the boo boo, re reading Don's PDF on making Concentric coil for the idx, Don does mention that the TX and RX on u1 pin 6 should be out of phase which is not in my case with any of the coils including the coil Don has made.

[kt315]

for starters unless i'm mistaken which is very possible, the IDX red board does not have an all metal or disc mode, it has a normal beep detection mode and a Point point mode which is an audible threshold hummmm, the only way to get a metal mode as you might think of it, is to turn the Disc pot down to 0, in anycase, i was getting the 42- 45 in beep mode with disc pot halfway just before losing the nickels. hope that what you needed to know.

what schematic you got with the board? would like to look what-it-is.
pleasure

[SWL]

This Classic diagram shows everything ...

[Tibuck19]

what schematic you got with the board? would like to look what-it-is.
pleasure

I dont have the schematic for this board i believe, the board is the Red one that Silverdog sells, the schematic i am trying to use as a reference is an older one with the VR Trim pots mounted to the board itself.

[Tibuck19]

Photo descriptions in order
first photo is Don's coil Ground balanced with a ferrite core top form is TX and Bottom is RX both at the same volts per division. TX is probed on Pin6 U8 and RX on Pin6 U1


Second is with the 10 inch F coil Ground balanced with a ferrite core top form is TX and Bottom is RX both at the same volts per division. TX is probed on Pin6 U8 and RX on Pin6 U1


Last photo is with 6B 8 inch coil that use to work perfectly and no longer works right, Ground balanced with a ferrite core top form is TX and Bottom is RX both at the same volts per division. TX is probed on Pin6 U8 and RX on Pin6 U1. Notice the step ladder effect on the RX (Bottom form) and notice how its amplitude is greater than the TX which is the opposite to the two other photos.

[Tibuck19]

This Classic diagram shows everything ...

this one does seem to resemble the board more than the one i posted

[kt315]

I dont have the schematic for this board i believe, the board is the Red one that Silverdog sells, the schematic i am trying to use as a reference is an older one with the VR Trim pots mounted to the board itself.

[ATTACH]54306[/ATTACH]
[ATTACH]54307[/ATTACH]

thank you. the sch taken from the forum.
you have to see two parts on the sch. one part is working independently from another.
EITHER pinpointing mode OR disc mode that you choice.
certainly you are seeking in second mode alltime at field.

[Tibuck19]

thank you. the sch taken from the forum.
you have to see two parts on the sch. one part is working independently from another.
EITHER pinpointing mode OR disc mode that you choice.
certainly you are seeking in second mode alltime at field.

Indeed i do understand that, so what are you trying to tell me? somehow the two halves are interfering with one another?

[kt315]

NOT. i am trying to tell you that you did whole job in vain. now you destroyed a metalization in pcb's holes somewhere
in result of the desoldering and just added new troubles.