MANUAL NEEDED, For A Compass MAgnum 420

[Functional]

Actually, I don't need the whole users manual. Just the part on using this Compass. I can get it to work, but I keep wondering if I"m missing any little tidbits of information, that might help improve my limited knowledge of the machine. It took me awhile, just to figure out what the letters "PT" and "BC", stood for, by the "Discriminate" knob.

Any advice on the use of this machine would be appreciated. I mainly plan to use it for nugget hunting and relic hunting around old prospectors cabins, but I suppose coin/jewelry shooting will be unavoidable.


I have to admit that I don't like that the knobs on this machine as they don't have a pointer, or any real markings, (with numbers), to line up a point on the knob to correspond with a particular value, so that you can increase, or decrease the settings and return to previous settings without a lot of guesswork.

I'm thinking of finding some printable vinyl, like they use for labeling CD's and make a new layout for each knob. Just pop the knob off, (unscrew), and overlay the new pattern. Then make a pointer/indicator, (round piece of painted metal with a small arrow), to fit under and attach to the bottom of the knob. I could probably use some of the same vinyl, to make a better indicator for the meter also. I think I'll have to get into the city soon and see what materials I can find.

F.

 

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[U.K. Brian]

Its a 10.5kHz machine so reasonable depth and discrimination. Bit heavy I remember (4lbs ?).
The all metal mode is the deeper in any mineralized ground with a quick flick into TR to check each target.

On the beach (wet/damp sand) you will find you can tune out the salt effect with the discrimination control. Needs to be where silver paper is just discriminated out. Don't go higher as you then lose depth as well as gold rings.

One feature that Compass were very proud of at the time was the 60 cycle rejection circuit. This did mean it could be used where other machines went erratic.

You could get 8" and 12" loops but if you pick up the 12 you need the hip mount kit and its still to nose heavy for comfort. You mention gold hunting and thats not its strong point for small gold. They had a 3" Tri Planer and 5" loop for the Coin Magnum and the B series machines but I never saw one for the 420 or 320.

I don't think battery life was that good as it only used 6 AA's but it came supplied with re-chargables so you could buy some without worrying about loss of performance.

You do need to mark the control box. It was supposed to have a scaled discriminate control but as you have found out that means a few dots.

Stick with it. Many of these older machines can outperform the new when you find the type of site/job that suits them. Be great to hear how you get on. I've seven or eight old clunkers but they all have their uses.

 

[Functional]

Its a 10.5kHz machine so reasonable depth and discrimination. Bit heavy I remember (4lbs ?).
The all metal mode is the deeper in any mineralized ground with a quick flick into TR to check each target.

I do like having that switch handy. I'm keeping my eyes open for an alternative handle that would allow the control box to be mounted farther back, or lower. I've seen some DIY modifications, like the one done by another TNet member Willy and I think I can do something similar. I have a carrying harness for a saw that would make the weight less of an issue.

On the beach (wet/damp sand) you will find you can tune out the salt effect with the discrimination control. Needs to be where silver paper is just discriminated out. Don't go higher as you then lose depth as well as gold rings.

I'm going to have to do some testing to find out where everything is. The lack of any indicator on the meter to say whats below is something I'll try and address.

One feature that Compass were very proud of at the time was the 60 cycle rejection circuit. This did mean it could be used where other machines went erratic.

Cool.

You could get 8" and 12" loops but if you pick up the 12 you need the hip mount kit and its still to nose heavy for comfort. You mention gold hunting and thats not its strong point for small gold. They had a 3" Tri Planer and 5" loop for the Coin Magnum and the B series machines but I never saw one for the 420 or 320.

I talked to someone that said they might have a 3" coil for it. I think it was called a "Magnum Prospector" coil. I really don't want to go for the tiny gold as there is so much flake gold around the areas I'm going to use it, that I'd be digging constantly. I do plan to still pan, but sometimes I find an area that I think I'd be better off using something else and they don't like dredges, or sluice boxes in the designated "Gold Panning Reserves" here.

I don't think battery life was that good as it only used 6 AA's but it came supplied with re-chargables so you could buy some without worrying about loss of performance.

I was actually thinking of getting a "GelCel" external battery, but I don't know if they come in 9 volt. If not, I'll stick with rechargeable AA's, so I can use the same battery charger as my camera.

You do need to mark the control box. It was supposed to have a scaled discriminate control but as you have found out that means a few dots.

Thats the one thing I haven't been too impressed with. That and the meter. And then theres the handle.

Stick with it. Many of these older machines can outperform the new when you find the type of site/job that suits them. Be great to hear how you get on. I've seven or eight old clunkers but they all have their uses.

I'm trying to wind up several projects I'm working on here, including renovating an old travel trailer, which I hope will be usable in time for a nugget shooting/prospecting trip in mid July, or early August, (likely the latter). I'm also waiting to hear back from the fellow with the 3" coil and I need to either replace my 8", or replace the cable, which I'm told isn't a simple task. It still works as is, but I don't know how long the coil will keep functioning the way it is.

F.

 

[U.K. Brian]

Nice to do up a trailer to suit your needs and I should get that small coil for that gold expedition.

If the cable is shot near the top from wear from hip mounting then you can trim it down with no worries its not like some that require the length to in effect tune the coil. You should also find that the machine works a little better with the cable run in a straight line up the top of the shaft.
If the problem is down near then coil due to flex then you could cut it off leaving a few inches and splice on which stops any possiblity of having to open up the coil.

Is 'Broken Detectors' still going? They may well have a replacement coil. They just don't seem to turn up on E-Bay very often.

 

[Functional]

Nice to do up a trailer to suit your needs and I should get that small coil for that gold expedition.

Even though the trailer needs alot of work, I'm sort of enjoying the opportunity to customize it and install some hiding spots during the renovations. Unfortunate for the previous owner who was told by his landlord that he had to get rid of it in a hurry, right before last Christmas, but fortunate for me that he let me have it for the price of towing it away.

Another lucky thing, is that I'd tracked down the guy with the Magnum parts from the internet and it just so happens he is a member and sometimes poster to TNet. He's got parts for several older machines and is still digging to see what other parts he can send me for the Magnum.

If the cable is shot near the top from wear from hip mounting then you can trim it down with no worries its not like some that require the length to in effect tune the coil.

Actually, the cable is blistered in places and feels sort of brittle, or stiff, as though the insulation inside hardened in spots due to the exposure to the heat of the fire.

You should also find that the machine works a little better with the cable run in a straight line up the top of the shaft. If the problem is down near then coil due to flex then you could cut it off leaving a few inches and splice on which stops any possiblity of having to open up the coil.

I'm going to try testing the cable for resistance while slightly flexing the coil and see if there might be a break that only appears when the cable is "bunched up", like when I had the coil rod collapsed before. It wasn't until I straightened the cable by extending the rod out, that it seemed to start working properly. I'll clean the connector to the detector housing while I'm at it.

Is 'Broken Detectors' still going? They may well have a replacement coil. They just don't seem to turn up on E-Bay very often.

Yes. www.brokendetector.com
I had emailed Keith Wills just before I heard back from the fellow I mentioned with the Magnum parts and he said he could sell me a length of replacement cable. The following is a quote from his email:

"There is a lot more to replacing the cable on a Magnum Compass 420 model. To do it correctly, you have to cut the coil itself open and you'll need a new top for the coil and cable sleeve and you can dig the cable O ring out of the old top and use it again. Then after replacing the cable, you'll have to reseal the coil to be water-tight with MEK and plastic solution so both halves will be fused into one again. Then you can solder the other end of the cable to your connector that attaches to the detector itself. If you can accomplish all this, then the cable is $1.10 a foot and we have it in stock. Shipping is $5.00. Hope this helped."

Reasonable enough price, but I'm not so sure I want to tackle the job if it involves opening up the coil, (unless I have another coil to fall back on, just in case). I also found another supplier, (Diversified Electronics in Burnaby, B.C.), who has some old stock of coils for the Magnum for $30.00 Canadian, but they only had the 8" and 10" coils. I may end up grabbing one of the 10" and then I'll be free to dissect my 8" coil to try replacing the cable.

Still no luck here with finding a manual yet though. Even Keith Wills didn't seem to have one. I don't really know how much information the manual would have that I couldn't find on the web, but so far I haven't found much through Google. If all else fails, theres always the trial and error approach.

F.

 

[U.K. Brian]

Try here

This site has many manuals (not yours) but if you look near the bottom of the page they have added some as requested by different machine owners.
Might be worth asking if they can help.
Worth a try. I've lots of manuals myself as I have loads of machines and never traded in anything good for a new model that often turned out to not be an improvement. Unfortunately I don't have the one you need.

Best of luck

 

[Functional]

Uhmm... Was there supposed to be a link in your post? I tried highlighting everything just in case there was and it was in white on white, but couldn't see it.

F.