IDX-PRO+VDI

[wlewis]

Hey koala & all.. I finally finished the pcb and Don's coil and not getting results - not even close. Uhmmm help?

1) the mpsa13 fried (despite an 8ohm low watt speaker) so I replaced it with a 2N6039G and heat sink - the heat sink gets hot after a while - is that normal?

2) am getting aprox a 6.5khz signal out of the speaker and about the same across coil caps. I need help nulling.

otherwise .. hey, nothing exploded (beside the mpsa13) so I can't complain.

[Koala]

MPSA13 should be cold something is wrong. Check all resistor values with meter only two measure wrong because they are in parallel. Make sure transistors are the right way round especially if you have used equivalents. Post a good quality image if you can't find the fault.

[mohandes]

Hey koala & all.. I finally finished the pcb and Don's coil and not getting results - not even close. Uhmmm help?

1) the mpsa13 fried (despite an 8ohm low watt speaker) so I replaced it with a 2N6039G and heat sink - the heat sink gets hot after a while - is that normal?

2) am getting aprox a 6.5khz signal out of the speaker and about the same across coil caps. I need help nulling.

otherwise .. hey, nothing exploded (beside the mpsa13) so I can't complain.

you make CC coil ?
if make DD coil all my friends and gurus help me just read last posts

[wlewis]

MPSA13 should be cold something is wrong. Check all resistor values with meter only two measure wrong because they are in parallel. Make sure transistors are the right way round especially if you have used equivalents. Post a good quality image if you can't find the fault.

I'm going to reinstall the mpsa13 check for faults and upload pics. Its good to know the 13 is supposed to be cold.. thanks.

mohandes.. yes its don's CC coil.. i'll be uploading pics soon.

[mohandes]

I'm going to reinstall the mpsa13 check for faults and upload pics. Its good to know the 13 is supposed to be cold.. thanks.

mohandes.. yes its don's CC coil.. i'll be uploading pics soon.

if you can not find error, make mirror print (180deg) of this pcb and check with your pcb to find any error in teragets (copper lines on your pcb )

[wlewis]

if you can not find error, make mirror print (180deg) of this pcb and check with your pcb to find any error in teragets (copper lines on your pcb )

Thanks.. already did that.

So far I've found 2 shorts and 1 incomplete trace.. good grief. Anyway, I'll be back-tracing from Eduardo's final pcb - the one without the diodes.

[mohandes]

Thanks.. already did that. [ATTACH]27341[/ATTACH] [ATTACH]27342[/ATTACH] [ATTACH]27343[/ATTACH]

So far I've found 2 shorts and 1 incomplete trace.. good grief. Anyway, I'll be back-tracing from Eduardo's final pcb - the one without the diodes.

you should remove one of them
and i put for one of them 2.7zener ,careful 180deg turn it .
i sure make mirror print (180deg) of this pcb is very good for find the errors.
and you can change another values in last posts of this pcb.just remove one 4148.
and if you learn me more about your CC coil i so happy.
regards

[seadoggy]

hi all gurus and friend
i add Attachment 26873 and in this i put for C , 100n( between pin5-8 ne5534 )and my nulling figure is 650mv(ne5534-6)
then :
i put the SENS on the max depth then find the best caps for the RX coils (stability and best depth near 32 - 33cm for 2000Rial )and it is for me 22n+22n+1.8n+1.8n
i set DIsC on fully CW(for reject iron ) then get test in my video and put it here.
in video i put by pice of ferrite 5.1cm and i can not reject it , and can guide me more ????(need to adjust for discrimination )
sorry for my bad QUALITY video, ( and i can not find 1EURO in my city ) so i measure by 2000Rial,1000Rial,ferrite , silver ring in this video

[ATTACH]27223[/ATTACH][ATTACH]27224[/ATTACH][ATTACH]27225[/ATTACH][ATTACH]27226[/ATTACH]

my video
http://p30up.ir/images/5hxo0jhaoa5dfzqsq.zip

hello mate i see your video!!how you connected 2 tone board in IDX pro board??

[wlewis]

you should remove one of them
and i put for one of them 2.7zener ,careful 180deg turn it .
i sure make mirror print (180deg) of this pcb is very good for find the errors.
and you can change another values in last posts of this pcb.just remove one 4148.
and if you learn me more about your CC coil i so happy.
regards

ill give this a try

I got it working marginally, detected aluminum and copper .. the signal is weak. If i turn up the sensitivity its crackles - saturation?

[mohandes]

ill give this a try

I got it working marginally, detected aluminum and copper .. the signal is weak. If i turn up the sensitivity its crackles - saturation?

if all parts is ok , please read my last ? from gurus gulfnot and koala
do you find the value of nulling in ne5534-6?how much for you ?
look , i OFFER to you DD coil.
that sound maybe from threshold pot or ...
regrads

[mohandes]

hello mate i see your video!!how you connected 2 tone board in IDX pro board??

i use master post , by elderado

[ossamaussama]

question
what is better use D3 as zener diode or 1n4148
why they use zener diode?
who can analysis the circuit?

[Koala]

I tried both. Both work very well. Very little to choose between them. I preferred the zener. Scattered a lot of targets on the ground and somehow found it easier to pinpoint with the zener. Since then I have been told that the recovery time is less with the zener I am not going to retest but would make sense as to why it felt better.

[golfnut]

The single diode could be considered a 0.7 volt zener. Some versions have 2 diode in series = 1.4v zener. 3x0.7 = 2.1v zener action etc. You can put a 2v7 volt Zener on and that acts like a 2.7v diode drop. The thing to watch is, if the silkscreen has a 1n4148 diode and you want to put a zener in - it must go the opposite way round. Because zener breakdown is from the cathode to anode and a forward volt drop of forward conducting diode goes from anode to cathode. S

[wlewis]

The single diode could be considered a 0.7 volt zener. Some versions have 2 diode in series = 1.4v zener. 3x0.7 = 2.1v zener action etc. You can put a 2v7 volt Zener on and that acts like a 2.7v diode drop. The thing to watch is, if the silkscreen has a 1n4148 diode and you want to put a zener in - it must go the opposite way round. Because zener breakdown is from the cathode to anode and a forward volt drop of forward conducting diode goes from anode to cathode. S

Is the replacement of the diode (D3) with a 2.7v zener the only "valid" mod on this board?

I didn't get results using Eduardo's pcb version without the trimmer. I'm going back to silverdog's version.