Sniffer XR-71 help

[Jafar]

i am thinking you have to look on all banch of photos in a folder turkish_PCB in the Archive, i see you have not wires on your pcb. lost.

you do (try to do) turkish layout of shiff sniff. much people got good result, but also much people got nothing.

I couldn’t find the archive folder you mentioned. If you have the link, I’d appreciate it if you could share it.

I replaced two LM555 ICs (used in an astable circuit) with NE555s because I didn’t have the original ones. Also, I substituted the UA556 IC (where the first section, D1A, is astable and the second section, D1B, is monostable according to the schematic) with an NE556. Can you help me rebuild the circuit using the replacement ICs I mentioned, based on whether each part is astable or monostable?

Also, in the UA556, pins 3 and 11—which are both control voltage pins—are not connected to _E via a capacitor. What’s the reason for that?

warm regards

[kt315]

i am thinking you have to look on all banch of photos in a folder turkish_PCB in the Archive, i see you have not wires on your pcb. lost.

you do (try to do) turkish layout of shiff sniff. much people got good result, but also much people got nothing.

[Jafar]

I took a quick look, I assume the "P" numbers are test points.
555 timers come in both bipolar and CMOS technology. Sometimes it is critical that you get the right one.

"Thank you, Carl. I know you're amazing when it comes to metal detectors, and I’m sure this is just a warm-up for you. I’d really appreciate it if you could guide me further, and I’d also love to get help from others who’ve worked in this field so I can get my device up and running."

[Carl-NC]

I took a quick look, I assume the "P" numbers are test points.
555 timers come in both bipolar and CMOS technology. Sometimes it is critical that you get the right one.

[Carl-NC]

I've moved you posts to a new thread. I don't have any experience with the Sniffer circuit, maybe someone else can respond.

[Jafar]

359704040-sniffer-xr-71-kit-manual-instruction.pdf
Esquema_Pulse_delta[1].pdf
Lista_de_componentes[1].pdf
NEW_SINGLE_FACE_PULSE_DELTA_010410[1].pdf
Posi.pdf

[Jafar]

An unfortunate reality with the old White's detectors is that the rotary-slide switches (used for mode selection) eventually go bad. There is no replacement.

Hi Carl, I need your help.

I've built the Sniffer XR-71 device, but I'm struggling with some issues and could really use your support.

One problem is that no signal appears on the oscilloscope under normal conditions—unless I touch pin 7 of the NE555 directly with my hand. When I do, a signal appears, but as soon as I let go, the signal disappears and the circuit stops working.

I'm also having trouble with the potentiometers. When I observe the signal on the oscilloscope, only the TRESH potentiometer seems to work—it adjusts the frequency between roughly 23 to 30 kHz. The other potentiometers don’t seem to have any effect. For example, the GAIN potentiometer doesn’t mute the sound, and the speaker stays on constantly.

Also, since I didn’t have an LM555, I replaced it with an NE555.
And because I didn’t have a UA556 either, I used another NE556 instead.

Please let me know what each of the pins labeled A1 and P1 to P9 are for.
If you’d like, I can send you photos of any part of the circuit or check it with the oscilloscope.

I’ll also send you the schematic and PCB layout.