Modified Harbor Freight Pinpointer w/ pics

yes!

basically what I did was just clip all the wires at one time, without labeling them, since they were un-insulated. Wouldn't the wires all ground together when they touch? Are these wires coated in a clear varnish to keep them from grounding? I will try to find the "Shorted wires" and connect as you mentioned.
 
Hi Pulltab
What I meant by uncovered was having no plastic insulation on, Yes they should be covered in a layer of varnish to stop them shorting on each other,
There is no stopping you putting some sleeving on the full length if you feel it needs it.
I usually put a sleeve on where I solder two wires together just to be on the safe side.
Good luck Cloggy
 
The wires are insulated with a coat of varnish, I took very fine sandpaper and gently removed the varnish one at a time I clipped sanded and reconnected using hotglue. I found the it was difficult to keep it from falsing due the length of the cord going from the box to the wand,
 
Been there, done that. Bought the HF body pointer, made for finding guns, knives etc on someones body. Modify'd it, added vibrators, and all to it! I was impressed.......till I got my hands on a Garrett Propointer, thats when I learned just what a pinpointer was. Now you can yell B.S. and enjoy your little toy, but if you ever get your hands on the Garrett (equelled by no-one) you'll toss the HF in the round can! It's like going from a Whites 1960 BFO detector to a Minelab. No joke.......! Naw, I don't work for them. They make an Exceptional pinpointer, that's all. When you get a penny about 2 inches away from it it starts making a slow ticking noise. The closer you get the penny the faster the ticking gets. Then theres the penny trick. By preloading with a penny, you can find a .177 cal BB or a small nugget about an inch away. I kid you not. That's my 2 cents worth. For what it's worth.

After spending several hundred dollars buying a machine,in this economy,Some folks have to wait awhile to afford a Garrett Pinpointer.I am sure most here would like to own one,as they seem to be the Cadillac of pointers,but price is a consideration with other things that are due to be paid monthly as well.If i had another $130 to spend when buying my machine,i would have bought the next model up,so i still would not have had an expensive pointer.Some of us own the HF pinpointer because it's better than not having a pointer at all,and when you're there,being able to get two for $32 bucks if one breaks or is lost,is still better than doing without.I have done air tests on coins with it also and it is still within a respectable range,and for the amount of time i acually use it,it still suits my needs.I have a hard time justifying spending $130 for a handheld pointer,when i can buy a brand new Ace 150 for $20 more,to take someone along detecting with me,and get them interested in the hobby.Thats just my opinion as well.Some would agree,some not.
 
Has anyone had problems using the HF detector in the heat?? If it gets about 100deg. it will not shut up!! Anybody else have this problem?? I havent done any mods to it yet. Another thing, sometimes when it is working right, if I turn the shaft towards the ground ie. upside down it goes off also(no metal around) almost as if something is loose and moving inside...... Any help or ideas???

EDIT- Ok, I tested out my theory.
1. Put a mark on sensitivity knob at the point it wouldnt beep
2. Put the detector in the sun and got it warm
3. Try it out in same spot and it beeps like crazy until I turn sensitivity knob way down.
4. Put on A/C vent to cool it down and now I can turn the sensitivity knob alot higher than in step #1

To sum it all up heat has a very negative effect on this detector, guess I have to bring a cooler with me! :)
Anyone else have this problem with any other brand of PP? Or is it just the HF one? Or just mine lol

yes i left it in the car in florida heat and noticed a big difference in sensitivity.took it in the house and the next day tried it and it was fine
 
Great thread. I do like the Centech. I like that it is cheap enough that people are willing to modify it with out worry.

I love the Idea of having it on a length of cable so that the main unit can be belt held and then the probe is hand held by itself..

Dave
 
Cen-Tech Temp Stabilization

I guess I can't really call this a mod, since the the component I added is labeled on the circuit board but not actually installed. I will just call it an upgrade. Thanks to XeXorZ and Valhad for reverse engineering the schematics. As most who use the Cen-Tech pinpointer know, it is not stable in hot or cold weather. Cen-Tech designed a NTC thermistor into the circuit but I guess they decided it cost too much to install it. I studied Valhad's latest schematic and did a little math and decided that the optimum value for the thermistor would be one with a room temperature value of 100 ohms. A friend was ordering some parts from Mouser and kindly let me add my part to his order so I didn't have to pay shipping for single part. (Thanks Glen) This is a link to the page for that part.
http://www.mouser.com/ProductDetail...56-59-D1/?qs=sGAEpiMZZMtYFXwiBRPs0yi5Kr7KS3Ts
I soldered it into the provided holes, adjusted the external pot to the center of it's travel, turned on the pinpointer with no nearby metal at room temp and adjusted the internal pot VR1 (the blue device with a screw adjustment) until it reached the threshold of sounding off. I then put the unit back together and placed it in the fridge. After half an hour I took it out and tested it. No problem adjusting it with the external pot to a point for proper function. I then used a hair dryer to raise the temp of the pinpointer to around 120 degrees, simulating use in the sun on a 100 degree summer day. Worked perfectly! This is a simple upgrade that the manufacturer should have done and well worth the price.
Good Luck!
Ron
 
All this modding maddness makes no sence to me lol. Who can I send my centech with $20 to make it wired with a nodded on/off switch on the "probe"
 
I'm about half a click between bad and worse when it comes to electronics, so I bought 2 of these so I could ruin the first one with my soldering iron as a science project. As you know science is a tricky thing that we don't yet understand. Somehow mine was working just like it was supposed to when I finished the switch and vibration motor. now I have a spare to loan out or use for spare parts when my workmanship unravels. Don't be scared to give it a try. 17 bucks for the centech, 8 bucks on parts and an hour of my time that no one would pay a dime for. The way I see it I'll save thirty bucks on gloves not having to scavenge in the dirt for five minutes every time my detector beeps. HH
 
Damn this pin-pointer rocks now. I ran a CAT5 wire and installed a switch and vibrator in the water proof wand. I truly enjoy using this PP now. I like to refer the last mod on the cen-tech "Icing On the Cake". Installing a thermistor on the NTC slot. Thanks to everyone posting about this mod, Ultralightpilot, and this youtube video http://www.youtube.com/watch?v=BQ-Vub0D1IA
 
electronics schematics

Somebody have electronics schematics of this circuit??
Thanks.
 
This kind of mod is right up my alley. I see a trip to HF in my near future :)
 
I guess I can't really call this a mod, since the the component I added is labeled on the circuit board but not actually installed. I will just call it an upgrade...

Greetings Ron, and many thanks for the write-up!

I ordered a total of ten 100 Ohm NTC thermistors from a eBay seller for only $2.50 shipped - and just installed the upgrade/mod to both my pinpointer and my dad's. Now the pinpointers will work in the hottest summer, I'll be able to use it year round now unlike last summer.

I did the hair/blow dryer trick to test my pinpointer before the upgrade. It didn't take long to heat it until it was unusable and always on. I preformed the upgrade and tested again. I was able to heat the pinpointer till even the hotglue around the upgraded switch got soft (way hotter than before) and it still worked normal - and had 40% of the knob turn left for adjustments!

No more worrying about not using the pinpointer or wrapping it with a icepack in summer (the only trick that worked last summer). :laughing: Thanks again - it's hard to believe only $0.22 in parts fixed two pinpointers so they will work no matter how hot it is outside!
 
This helped a ton. Thank you!!!!!!!

:d:d:d
i guess i can't really call this a mod, since the the component i added is labeled on the circuit board but not actually installed. I will just call it an upgrade. Thanks to xexorz and valhad for reverse engineering the schematics. As most who use the cen-tech pinpointer know, it is not stable in hot or cold weather. Cen-tech designed a ntc thermistor into the circuit but i guess they decided it cost too much to install it. I studied valhad's latest schematic and did a little math and decided that the optimum value for the thermistor would be one with a room temperature value of 100 ohms. A friend was ordering some parts from mouser and kindly let me add my part to his order so i didn't have to pay shipping for single part. (thanks glen) this is a link to the page for that part.
http://www.mouser.com/productdetail...56-59-d1/?qs=sgaepimzzmtyfxwibrps0yi5kr7ks3ts
i soldered it into the provided holes, adjusted the external pot to the center of it's travel, turned on the pinpointer with no nearby metal at room temp and adjusted the internal pot vr1 (the blue device with a screw adjustment) until it reached the threshold of sounding off. I then put the unit back together and placed it in the fridge. After half an hour i took it out and tested it. No problem adjusting it with the external pot to a point for proper function. I then used a hair dryer to raise the temp of the pinpointer to around 120 degrees, simulating use in the sun on a 100 degree summer day. Worked perfectly! This is a simple upgrade that the manufacturer should have done and well worth the price.
Good luck!
Ron
 
Great modifying job. I'm going to give it a try. Tip: Get you a package of heat shrink tubing from HF. It's so much easier to work with on small wires.
 
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