XR-71 Sniffer PI schem+PCB

[mollax]

hi max. you shoot second time... what you say about to learn SEARCH engine in the Forum GEOTECH?
Vladimir D. asks me put a file of PCB in .LAY format, Sprint Layout-4. now you have all files to do The Thing.

truly yours

this PCB faulty

[kt315]

You posted the board on the left a few years ago in post #7. What is this additional piece (in yellow box) added to this pcb? I have the pcb on the right, but I would be interested in the other. Do you have the schem and pcb layout?

Thanks so much!

i repeat a letter again.

We haven't to speek for price. I'll send pcb not for money but for somthing similar. Last year I sent to Jurij some coil shells - you can ask him. My XR71 pcb is the same as "Aban" sent in Carl forum. He ("Aban" is pseudonim which one bulgarian boy have used. He is from Burgas and is very good liar.) He had stolen my pcb at the early 2000. This pcb have manifactured yet have a bit modification - we added a part with batery changer and lowbat indication. As you good know on pcb are swich for "Manual" - "Auto" tune which was soldered in "Auto" mode in "Aban" pcb. The main advantage my pcb is spetial selection for IC and pasive - You mast know this is "secret", because there were many XR71 detectors were manifactured but when you will test any from "VE EL electronics" you could register adventage. I have many detectors and think it was one of the best models at the time and can compare it.
About XR71 I can say that it "Father" XR7 (I had manifactured 3 devices before XR71) was one very fine designed Pi machine. If you are interesting I can send you shematics of XR7.
Best regards,
(deleted for privacy)

[mollax]

i repeat a letter again.

I fixed it everybody get a gift

[Darren in NC]

Mollax, what did you fix?

[mollax]

Mollax, what did you fix?

Some of them are more

[porkluvr]

I fixed it everybody get a gift

mollax,

If you are going to the trouble of re-spinning the PCB I have some other suggestions.

I do not think that the original PCB designer took into account that thru-hole plating would make the diameter of the holes narrower. Some component leads must be forced through the holes because of the space being too narrow. Make the R and C pads bigger where possible, and widen the holes

The damping resistor R5 should probably be a power resistor because of the high voltage spikes. The existing PCB layout only accommodates a 1/4W resistor. Pad diameter, pad spacing and hole size, are all wrong. R5 needs some attention.

Same goes for the receiver input resistor R6. R6 pads are laid out for a 1/4W resistor, but I see a power resistor in the photo. Also, I have someone's XR71 project to finish, and there is a power resistor installed at R6 as I received it. Come to think of it, a power resistor for R6 is not a bad idea but evidently that is not what the PCB designer had in mind.

Q1 (IRF740) pads could be larger and the holes wider. Why not make those bigger? I damaged pads because I could not get all of the old solder to wick when I needed to reposition Q1.

Tight specs might be great for industry, but not so good for the average hobbyist. Vias being larger than solder pads seems like nonsense to me.

[mollax]

mollax,

If you are going to the trouble of re-spinning the PCB I have some other suggestions.

I do not think that the original PCB designer took into account that thru-hole plating would make the diameter of the holes narrower. Some component leads must be forced through the holes because of the space being too narrow. Make the R and C pads bigger where possible, and widen the holes

The damping resistor R5 should probably be a power resistor because of the high voltage spikes. The existing PCB layout only accommodates a 1/4W resistor. Pad diameter, pad spacing and hole size, are all wrong. R5 needs some attention.

Same goes for the receiver input resistor R6. R6 pads are laid out for a 1/4W resistor, but I see a power resistor in the photo. Also, I have someone's XR71 project to finish, and there is a power resistor installed at R6 as I received it. Come to think of it, a power resistor for R6 is not a bad idea but evidently that is not what the PCB designer had in mind.

Q1 (IRF740) pads could be larger and the holes wider. Why not make those bigger? I damaged pads because I could not get all of the old solder to wick when I needed to reposition Q1.

Tight specs might be great for industry, but not so good for the average hobbyist. Vias being larger than solder pads seems like nonsense to me.

porkluvr amen.I posted here PCB I want to state incorrectly that.
If you want the .lay file you are correct.

[Darren in NC]

This pcb have manifactured yet have a bit modification - we added a part with batery changer and lowbat indication. As you good know on pcb are swich for "Manual" - "Auto" tune which was soldered in "Auto" mode in "Aban" pcb. The main advantage my pcb is spetial selection for IC and pasive - You must konw this is "secret", because there were many XR71 detectors were manifactured but when you will test any from "VE EL electronics" you could register adventage.

So is this pcb file available in Sprint Layout or other layout?

[kt315]

http://www.geotech1.com/forums/showt...ighlight=share

it places in folder PCB from demchenko. Sprint Layout .LAY file.

[Darren in NC]

Thanks, but I already have the pcb in that file. I posted the picture above hoping someone has the pcb file for the XR-71 with a battery charger built in.

[mazari]

hi for all .i have built the XR-71 but i can't detect gold at anny distance .please can you help to solve this problem?thank you in advance

[loukilouk]

Hello! I am a new member and do not have much knowledge of electronics. Can anyone tell me if this design is right to convert the sniffer to 24 volts? Thank you very much!
https://postimg.cc/HJqKYvFs