Compass XP350

[DavidB]

This is the real Scanner with the famous vari-filters. Another one of my schematic projects. A
work in progress.

[Joe(TX)]

....Modifications on the XP-350....

....Want to get an XP-350 for a project....I was told a while back that this detector has all of the ports or whatever to add components to upgrade it to an XP-Pro...I bought a Coin Scanner as a Parts detector and plan to add the meter and maybe other controls to the XP-350..I already have an XP-450.....and in the rare case that I could not locate an XP-350....I could use this instead but at the moment would rather leave it intact.........would appreciate any comments .....Thanks....Joe

[kt315]

Joe, have you asked Kasparov to send schematics for the Treasure Baron machines? can you share here or send them to me? TIA.

http://compass-metal-detector-forum....td7188373.html

If anyone needs and schematics for the Treasure Baron machines let me know and I can email you a copy. I have a schematic for all of the modular Barons. I got these from George Payne some time back and he said that he did not mind if I shared these with others. All of these are really nice copies. So shoot me an email at [email protected] if you need one. Hope all of you have a great new year and make lots of nice finds.

[DavidB]

The XP-350 bd is the same as the bottom bd. used in the 2 board Pro. There is a picture of those 2 bds posted on this forum under coin scanner Pro. I have made the schematic for the Xp-350 and I will post it after I put it in a neat one page format. If the top bd on your pro is in good shape or at least repairable then you should have what you need for the conversion. The top bd circuit is for notch and target ID but the bottom bd circuit is the actual detector. I don't have a schematic for the top BD.

[DavidB]

Compass XP-350 schematic

Here is the freehand version

[Mrand]

I found errors. Resistor 82k which is connected to U3(1) should be connected to U3(5). Analogically situation is with U4.
Mrand

[DavidB]

You are right. I see that when I transferred the drawing over to a one page format I connected the offset adjustments to the wrong side of the capacitor. They are supposed to adjust the DC level on the non inverting inputs of the last filters. I don't think that I screwed anything else up.
When I get a chance I will take this detector to work and save some scope wave forms from the test points. I spent a lot of time tracing out this 25 year old detector. I hope this drawing will help some people with troubleshooting. I sure do appreciate all the different detector drawings that others have posted. I hope that others will continue to share. Not sharing metal detector schematics is pure evil.


DavidB

[DavidB]

Corrected schematic. Does anyone know where the vari-filter patent is or if it was even granted. All the detectors that I have seen say patent pending.

[Joe(TX)]

Vari-Filter Patent??

Corrected schematic. Does anyone know where the vari-filter patent is or if it was even granted. All the detectors that I have seen say patent pending.[ATTACH]22572[/ATTACH]

....David....I do not know...but there was a post on the CXXPASS forum that had a link to contact George Payne....he either invented the Vari-Filter or at least he knows who........I know that the fire at Compass was around 1994 or so??...and once the company disbanded and could not pay their employees...all of the engineers left and found employment elsewhere.....so if the patent was pending....the original person who started the patent probably figured that they would let it pass or started it back up under another name for their new employer....this is just an d educated guess since I really do Not know......

[Joe(TX)]

...David.....Thanks for your updated post...it reminded me of my Compass Scanner Parts Detector....I had completely forgotten about it....I think that I will dig it out and see how I can get it to working again or update it......

[Melbeta]

I believe that it was John Earle who came up with the Vari-Filter design, not George Payne. And I have never found the patent, so I think it may have not been applied for or they abandoned the patent application. George Payne came to Compass Electronics just around the time that John Earle left Compass, and returned to Whites Electronics. George Payne said in a quote on the internet that he had never met John Earle. George Payne also said that John Earle made the Vari-Filter, not himself. I believe that John Earle is still working at Whites Electronics. I found that somewhere.Perhaps Carl can comment on this Vari-Filter for us? How about it Carl?A true filter usually consists of a capacitor and a inductor, both in parallel, one or the other is tuned to bring the filter into the filter frequency. Other filters are a resistor and an inductor, both in parallel, and again one or the other is tuned to bring the filter into the filter frequency. If the filter design goes to ground, it is usually called a notch filter, which is what the option of a Notch selection in the detector really consists of, a Notch Filter. The Notch Filter can notch something into selection, or notch something out of selection, which I presume would then be to ground to eliminate the signal frequency. Correct me if I am wrong...Melbeta

[treasurehunter747]

Any more info on the XP350 schematic or the XP Pro? Thanks and I know this is an old post but what the heck? Keep on diggin!!!
Frank

[DavidB]

I almost have the entire schematic for the top BD ( notch, target ID) completed. I just started looking at it again this week. Pretty soon I will draw up the whole thing in Altium. I plan to route a SMD BD with some upgraded parts and a few changes for this. Would be nice to have a compact lite weight version of this classic favorite. Hang in there it is coming. I just have a lot going on.

[kt315]

[DavidB]

There are some other mistakes that need correcting. The base of Q7 connects to the collector of U6, not the emitter and there is a missing phase shift .0022Uf capacitor at the input of U12 pin 3 that connects to the minus 5V.