COMPASS COIN PRO II SCHEMATIC

[kt315]

you left me without the pics and good project.
toropyga khrenov bl. vyskochka.

[daverave]

thanks for the link for the operating manual

[daverave]

ive been tinkering with the compass and works ok then all of a sudden the tone ID stops working and go's into a single tone and then meter only go's as far as ring/pulltab section...i have no knowledge of these detectors or tone id...is there anyone with the knowledge to point me in the right direction of solving this problem ?????

[daverave]

also noticed when switched into auto notch there is no response from any metal just will not detect anything in this mode...i really need advice with these problems PLEASE

[daverave]

its very difficult probing on the pcb as both sides have a resin coating....the fault causes auto notch/multi tone/meter ID to fail together...but sometimes the fault clears for a couple of mins and all works correctly then the unit go's back into its fault condition...maybe a capacitor but im not sure ??? PLEASE CAN ANYONE ADVISE

[kt315]

advise just one - rego on Compass Metal Detector Forum http://compass-metal-detector-forum....n2.nabble.com/
i do not see your cooperative (((
Ego cultivating. that we call capitalistic egocentrizm. so much big problem grafted to you by the Levites.

[daverave]

thanks kt315 for your help.

[Melbeta]

DaveRave
Only know of one fellow here in America who works on the Compass metal detectors. He is Keith Wills, email address [email protected], company address First Texas Metal Detectors, 1495 FM49, Gilmer, TX 75644. Now he does not work on detectors outside the USA, but he might answer your questions. The main problem is what I said earlier, if it is a unit that Steve ran out of parts for, and sold anyway, then what can I say? Keith Wills used to be a Service Tech working for Compass Electronics, then left to open his own service company in Texas. He knows the detector, but if it is missing parts, then you have a problem. But you have a schematic for the first model which was the Coin Scanner Pro, and if you work for that schematic and replace any defective parts, starting from the power supply connections.

Keith Wills phone number is (903) 734-7773, but I suggest you try the email first and clearly spell out what the detector is doing and he may give you your answer where the problem is located.

Other then Keith Wills, there is no one in the Compass forum that knows how to fix the Compass machines other then Keith and PhaseShifter.
Melbeta

[daverave]

Hi melbeta....many thanks for your reply and the email of that compass service technician...i think the problem is a capacitor as the fault is intermittant....but of course which capacitor and as i know so very little about vlf motion machines its best if i can get advice rather than mess up the pcb looking for the capacitor...i hope that i can fix it as i like the compass very much and has good depth and good discrimination.

[daverave]

ive registered on the compass site that kt315 mentioned but the site will not allow me to post or even reply to anything which is very stressful...i have sent an email to keith wills for help but still waiting for a reply....just done more testing and detector works ok for several mins from cold then after a few mins the fault appears so i guess must be thermal problem.

[kt315]

try ask Sven directly. he is admin.

[daverave]

thanks kt315....you always willing to help people and im very grateful to you.

[Melbeta]

Once you have a schematic, get it printed out on paper at a local printing house. It is highly likely that Steve only moved some part controls around, but did not make much if any changes to the factory schematic. I know he added in a charger port to charge rechargable batteries, but that has been corrected on the schematic you have now.

Then you can take it to a TV or other electronics repair place to get it fixed. But the (resin) coating on top of the parts is a problem. Compass put it on to prevent moisture in the air from affecting the electronics. If one finds a chemical dissolvent and removes it where you want to test the capacitor, one can test each cap.

But you have to first discharge the voltage in the capacitor before testing, or it can damage volt meter using the ohm settings. And make sure you remove the batteries from the detector first, and then begin to discharge here and there to take away any residual voltage remaining in caps and other parts. And testing a cap, you have to unsolder one leg, in order to take an accurate ohm reading of the capacitor. So it is a better choice just to begin replace capacitors. Start from the power supply area, and concentrate first on the electrolytic caps. I used to first begin to feel the caps to see if one cap is hot. If so, that cap is passing too much voltage, so replace that cap. Too much voltage could have damaged another part in that area, especially a chip.

Now for guys like Keith Wills, it is easier for him to repair them, as he has in addition to the factory schematics, examples of the oscilloscope waveform readings for each TEST POINT. So he can hook up a oscilloscope to each test point, look at the wave form, and when he finds a distorted wave form reading, he has the problem area located. Then it is just a matter of taking voltage readings, compare the voltage reading for that position, and viola, he found the defective part or parts.

And that is what the TV or electronic service guy will do, but without the wave form readings and voltage part readings. It will take him longer but he can find the defective part by reading the voltage drops of parts. Of course, that factory coating with be a problem for him, but he will use a abrasive tool to grind a clear test spot on each of the parts he wants to check out. You know, like a Dremel tool with a small abrasive bit to grind into and remove the chemical coating. If voltage does not flow, or there is too great of a voltage flow, or a part feels hot, there the problem area is.
Melbeta

[daverave]

Hi Melbeta
i was told that these compass pcb's are three layer type so harder to fix...the resin is a real handicap in trying to fault find...i did think about rubbing the bottom of the pcb across some abrasive paper or maybe using a file to remove resin...its strange cause the detector normally works from cold on for a couple of mins...maybe a thermal problem with the solder connections..as the circuit warms up then maybe a dry solder joint causes the fault problem.....when i was in the television repair trade we used a can of freezer to locate thermal problem so maybe useful to locate the area

[kt315]

we must desolder all board and do a project for people. to measure every component and draw schematic in a CAD.