kimsdad
Silver Member
- Apr 17, 2008
- 4,692
- 24
- Detector(s) used
- E-trac & Bounty Hunter Land Star
Problems with your Harbor Freight Cen-tech pinpointer? How to fix 'em.
I'm posting this in case anyone out there purchased a Centech hand held metal detector from Harbor Freight for use as a pinpointer and is having problems with it. I bought one last year and I'm really pleased with what I got for my $16.95. I have a Sunray probe on my SE, but I still use the Centech to really narrow down those small targets, and it's the only pinpointer I use when I'm hunting with the DFX. I really beat the snot out of this pinpointer.
I've lost it in the woods over a real rainy night and it still worked when I found it again the next day and dried it out. I've hunted in powder-fine dust, and plunged it almost up the the box in mud water. I've pushed it into the mud and soft dirt and twisted and pried dirt with it. Since it was so cheap, I've treated it with little respect. What surprises me is just how easily it bounces back from all this abuse.
Over the course of this abuse, I've found that there are a few things that gave me problems. I was able to fix these, and I wanted to pass this info on so anyone else who isn't afraid to dig into it so they deal with them too.
First of all, I'm not looking for "Buy a real pinpointer and you won't have to deal with these things" replies. I get that. I don't want to buy a "real pinpointer". I'm more than happy to spend my hard earned clad on extra coils and other things like that.
Secondly, if you decide to try these remedies, you do so at your own risk. I make no claims that any of this is completely safe. There are risks in anything we do, and this is no exception. You could ruin your $16.95 pinpointer or hurt yourself while trying to fix it. Rubbing alcohol is flamable. Don't use it by a flame or heat source. Again, you assume any and all risks.
Third, before performing any maintenance on the unit, remove the battery.
That said, there are four things that gave me problems
That dirty rotten switch...
This was the first thing that I had trouble with on this unit. After several hunts in the dust, the switch got dirty and would only operate intermittently. It's not a sealed switch, so dust and moisture will get in it and cause problems. Not a big deal, the switch can be cleaned. After taking the battery out, open the unit by removing the four screws holding the back on. They are small screws, but can be turned with a 3/32" Phillips screwdriver from a precision screwdriver set. Carefully pull the back off, being careful not to pull it apart too much so you don't pull the wires to the speaker out.
Hold the unit so the switch is facing down. Put a folded paper towel under the switch. Apply drops of ordinary rubbing alcohol to the back of the switch where the contacts enter the case and start pushing the switch up and down on the paper towel. You should see the alcohol work its way into the switch through the gaps where the contacts go into the case. If the switch is dirty, you'll start to see dirt and gunk flow down around the red button and onto the paper towel as you work the switch. This dirt was fouling the switch. Keep doing this over clean sections of paper towel, adding more drops of alcohol until no more dirt comes out. Once it is clean, keep working and shaking the switch without adding more alcohol. This will help get the excess out. Then just let the whole thing sit out for a while to dry before reassembling it.
My switch gunks up a lot, so to make cleaning easier, soldered wire extensions on the switch and insulated the connections with heat shrink tubing. This makes it easier to clean the switch without having to deal with holding the pinpointer case. I simple remove the switch from the case and clean it as explained above. One of these days, if I come across a cheap sealed switch, I just might install it.
Hey, the tip isn't waterproof!
The tip of this unit is press-fit into place. It isn't waterproof. I waterproofed mine by gently prying off the tip, being careful not to break the coil wires. The coil is glued to the inside of the tip of the probe, so if you pull the tip too far, you might break the wires. Clean both surfaces with rubbing alcohol, let them dry, and apply a coating of silicone caulk to the part of the tip that fits in the probe. Press the tip back into place and wipe off all excess silicone. Allow it to cure for at least 24 hours. Now your tip should be waterproof.
My probe is loose!
Only after months of abuse, the screw holding the end of the probe to the inside of the case wore through the inside of the case and was loose. Simply replace this screw with a small bolt, lock washer, and nut. Just be sure the head of the bolt is bigger than the hole in the back of the cast that the original bolt fit into. Use a washer under the bolt head if it isn't.
Hey, there's gunk in the speaker.
One other thing I noticed. The speaker hole kept getting gunked up and the screen eventually tore. After cleaning the case, I covered the hole with a piece of blue masking tape. It keeps dirt out and you can still hear the beep.
This unit can be easily modified by anyone with electronics knowledge. It can be made to vibrate with an add-on vibrating motor, or a "target found" LED can be added.
Eagle77 has a great post of one of these mods here:
http://forum.treasurenet.com/index.php/topic,178515.0.html
I hope someone finds this post useful.
HH!
I'm posting this in case anyone out there purchased a Centech hand held metal detector from Harbor Freight for use as a pinpointer and is having problems with it. I bought one last year and I'm really pleased with what I got for my $16.95. I have a Sunray probe on my SE, but I still use the Centech to really narrow down those small targets, and it's the only pinpointer I use when I'm hunting with the DFX. I really beat the snot out of this pinpointer.
I've lost it in the woods over a real rainy night and it still worked when I found it again the next day and dried it out. I've hunted in powder-fine dust, and plunged it almost up the the box in mud water. I've pushed it into the mud and soft dirt and twisted and pried dirt with it. Since it was so cheap, I've treated it with little respect. What surprises me is just how easily it bounces back from all this abuse.Over the course of this abuse, I've found that there are a few things that gave me problems. I was able to fix these, and I wanted to pass this info on so anyone else who isn't afraid to dig into it so they deal with them too.
First of all, I'm not looking for "Buy a real pinpointer and you won't have to deal with these things" replies. I get that. I don't want to buy a "real pinpointer". I'm more than happy to spend my hard earned clad on extra coils and other things like that.
Secondly, if you decide to try these remedies, you do so at your own risk. I make no claims that any of this is completely safe. There are risks in anything we do, and this is no exception. You could ruin your $16.95 pinpointer or hurt yourself while trying to fix it. Rubbing alcohol is flamable. Don't use it by a flame or heat source. Again, you assume any and all risks.
Third, before performing any maintenance on the unit, remove the battery.
That said, there are four things that gave me problems
That dirty rotten switch...
This was the first thing that I had trouble with on this unit. After several hunts in the dust, the switch got dirty and would only operate intermittently. It's not a sealed switch, so dust and moisture will get in it and cause problems. Not a big deal, the switch can be cleaned. After taking the battery out, open the unit by removing the four screws holding the back on. They are small screws, but can be turned with a 3/32" Phillips screwdriver from a precision screwdriver set. Carefully pull the back off, being careful not to pull it apart too much so you don't pull the wires to the speaker out.
Hold the unit so the switch is facing down. Put a folded paper towel under the switch. Apply drops of ordinary rubbing alcohol to the back of the switch where the contacts enter the case and start pushing the switch up and down on the paper towel. You should see the alcohol work its way into the switch through the gaps where the contacts go into the case. If the switch is dirty, you'll start to see dirt and gunk flow down around the red button and onto the paper towel as you work the switch. This dirt was fouling the switch. Keep doing this over clean sections of paper towel, adding more drops of alcohol until no more dirt comes out. Once it is clean, keep working and shaking the switch without adding more alcohol. This will help get the excess out. Then just let the whole thing sit out for a while to dry before reassembling it.
My switch gunks up a lot, so to make cleaning easier, soldered wire extensions on the switch and insulated the connections with heat shrink tubing. This makes it easier to clean the switch without having to deal with holding the pinpointer case. I simple remove the switch from the case and clean it as explained above. One of these days, if I come across a cheap sealed switch, I just might install it.
Hey, the tip isn't waterproof!
The tip of this unit is press-fit into place. It isn't waterproof. I waterproofed mine by gently prying off the tip, being careful not to break the coil wires. The coil is glued to the inside of the tip of the probe, so if you pull the tip too far, you might break the wires. Clean both surfaces with rubbing alcohol, let them dry, and apply a coating of silicone caulk to the part of the tip that fits in the probe. Press the tip back into place and wipe off all excess silicone. Allow it to cure for at least 24 hours. Now your tip should be waterproof.
My probe is loose!
Only after months of abuse, the screw holding the end of the probe to the inside of the case wore through the inside of the case and was loose. Simply replace this screw with a small bolt, lock washer, and nut. Just be sure the head of the bolt is bigger than the hole in the back of the cast that the original bolt fit into. Use a washer under the bolt head if it isn't.
Hey, there's gunk in the speaker.
One other thing I noticed. The speaker hole kept getting gunked up and the screen eventually tore. After cleaning the case, I covered the hole with a piece of blue masking tape. It keeps dirt out and you can still hear the beep.
This unit can be easily modified by anyone with electronics knowledge. It can be made to vibrate with an add-on vibrating motor, or a "target found" LED can be added.
Eagle77 has a great post of one of these mods here:
http://forum.treasurenet.com/index.php/topic,178515.0.html
I hope someone finds this post useful.
HH!
Then I used clear silicone and totally sealed up all the openings and case so it not longer gets dirty, it looks like hell but it sure can take some abuse now!
