Hi out there, I was wondering if anybody knows where to get a vintage 1970 or 1971 Garrett BFO Master hunter repaired. I do have several modern detectors, but I would like to get my first detector usable again. A friend told me the oscillators go bad due to time and ones that work are still available. I would appreciate any info on this subject. Also, why don't they seem to make BFOs any more?? Thanks, Gunsil
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Old Garrett BFO
- Thread starter gunsil
- Start date
Joel-Winnipeg
New member
You might give Garrett a call and see if they can fix it.
If they can't ask them for suggestiones.
If they can't ask them for suggestiones.
Thanks Joel. Believe me, I tried Garrett first, and so did a friend with a slightly newer 1970s Garrett BFO. They said they no longer stock parts for the old BFOs but did graciously offer to give us something in trade on a new Garrett detector if we liked. Garrett has the best customer service and support as far as I am concerned, but I suppose it is unrealistic to expect any manufacturer to stock parts for, and maintain personnel who are familiar with repairing forty year old equipment. That is why I am searching forums, thinking there must be someone who actually can do the repairs on old equipment.
Happy New Year !!! ---Gunsil P.S. How does one put the quote at the bottom of their posts?? As in yours by Charles Kingsley.
Happy New Year !!! ---Gunsil P.S. How does one put the quote at the bottom of their posts?? As in yours by Charles Kingsley.
Joel-Winnipeg
New member
Gunsil just go to the top and see in between ( Log out ) and Members only messanging
click on ( Control Centre ) and follow the instructions
click on ( Control Centre ) and follow the instructions
Joel-Winnipeg
New member
gunsil said:
That is it.
Gunsil,
You might check with www.brokendetector.com
The owner is well known for fixing older detectors.
What is your BFO doing wrong? I have an old Garrett BFO that wouldn't work when I got it. In my case, one of the pots was frozen. A little WD 40 cured that problem and brought the detector back to life. Hopefully, your detector is a simple fix.
I also have an old Bounty Hunter BFO that didn't work and it was a simple fix also. In this case, the off/on switch located on the back of a pot wasn't working. Again, a shot of WD 40 cured the problem.
So, sometimes the fix can be quite simple.
Is your Garrett BFO one of the discriminating types? If so, some of the circuitry is potted which could make it more difficult to fix.
Reg
You might check with www.brokendetector.com
The owner is well known for fixing older detectors.
What is your BFO doing wrong? I have an old Garrett BFO that wouldn't work when I got it. In my case, one of the pots was frozen. A little WD 40 cured that problem and brought the detector back to life. Hopefully, your detector is a simple fix.
I also have an old Bounty Hunter BFO that didn't work and it was a simple fix also. In this case, the off/on switch located on the back of a pot wasn't working. Again, a shot of WD 40 cured the problem.
So, sometimes the fix can be quite simple.
Is your Garrett BFO one of the discriminating types? If so, some of the circuitry is potted which could make it more difficult to fix.
Reg
Thanks, Joel, got it, am learning. Hi Reg, my BFO is pre-discrimination. My friend has one a year newer and he has an electronics buddy who looked at his and evidently there is a capacitor or two that have limited life expectancy. I do have a corroded battery connection which I am going to fix myself. I'm not sure what else is a problem, but several years ago I lent it to an ex-girlfriend who once had the same machine and she gave it back saying it didn't work, and that was with good batteries. I suppose I should fix the battery connection and then see how it acts or doesn't act. I suppose if I knew what capacitors to order and find out where to get them I could do that myself, too, I am OK with a soldering iron. I am hoping there is somebody really familiar with fixing these machines who can give me pointers like if I can test the capacitors. The tip about WD on the pots is a good one. They also sell a pot cleaning/lubing spray which I should get some of.
Thanks for your input---------Gunsil
Thanks for your input---------Gunsil
Hi Gunsil, You might give Keith Wills a call (www.brokendetector.com). He does have some parts for the older rigs. If he can't find a part for you, send me a pm. I have a lot of detector parts and pieces for Garrett, Gold Mountain and some D-tex.
Can you give us some idea of what your BFO isn't doing? If a battery terminal, or connection is bad, repairing it may very well solve your problem. I/We will be interested in knowing what really does fix the old Gem. :0))
John London
Amarillo, Texas
Can you give us some idea of what your BFO isn't doing? If a battery terminal, or connection is bad, repairing it may very well solve your problem. I/We will be interested in knowing what really does fix the old Gem. :0))
John London
Amarillo, Texas
Hi Gunsil,
Sometimes you can check a BFO to see if it is partly working by taking a cheap pocket radio and turn it to AM. Then turn the radio on and place the radio on the coil and slowly adjust the frequency tuning and listen for a squeel. I don't have my Garrett where I can get to it but I do have an old Bounty Hunter BFO and this test works on it. If I get a chance tomorrow I will try the test on the Garrett once I find it.
Do you have any test equipment, like a scope, meters, etc? Maybe we can help you check a few things. Once I get my BFO out of mothballs, I will do some tests on it that may help since my unit is a pre discriminator model also.
Now, my unit is one of the small boxes and not one of the larger boxes Garret started using at a later date. I don't have one of those.
Reg
Sometimes you can check a BFO to see if it is partly working by taking a cheap pocket radio and turn it to AM. Then turn the radio on and place the radio on the coil and slowly adjust the frequency tuning and listen for a squeel. I don't have my Garrett where I can get to it but I do have an old Bounty Hunter BFO and this test works on it. If I get a chance tomorrow I will try the test on the Garrett once I find it.
Do you have any test equipment, like a scope, meters, etc? Maybe we can help you check a few things. Once I get my BFO out of mothballs, I will do some tests on it that may help since my unit is a pre discriminator model also.
Now, my unit is one of the small boxes and not one of the larger boxes Garret started using at a later date. I don't have one of those.
Reg
Gunsil,
I was wondering about your BFO and whether you got it going. Can you update us as to what you found so far?
BTW, I found an old Garrett Master Hunter BFO on craigslist and bought it for $50 shipping and all. I am not sure if it works or not but I should find out here in a few days. I will let you know if I get mine going and if I do, I can take a few measurements for you.
I do have a question for those reading this post and that is, have any of you tried to add the discrimination feature to a BFO? I think it would be fun to try to do this.
Reg
I was wondering about your BFO and whether you got it going. Can you update us as to what you found so far?
BTW, I found an old Garrett Master Hunter BFO on craigslist and bought it for $50 shipping and all. I am not sure if it works or not but I should find out here in a few days. I will let you know if I get mine going and if I do, I can take a few measurements for you.
I do have a question for those reading this post and that is, have any of you tried to add the discrimination feature to a BFO? I think it would be fun to try to do this.
Reg
Gunsil,
I purchased a Garrett BFO, large box, and when I got it, it wouldn't work. In my case the transistor that is the transmit oscillator was bad. I replaced it and now the detector works fine. Unfortunately, this isn't something that can easily be tested except to make sure the signal isn't there and I used a scope to determine that. I used a simple cheap PNP general purpose transistor.
I also checked to see if I could hear a squeal when I held a am radio in the middle of the coil. When bad, I couldn't hear anything reliable, but once it was fixed, the signal heard in the radio was quite distinct. I don't know the exact frequency but on this cheap hand held radio, the signal was somewhere between 13 and 16 on the am dial.
Now, I need to find a small cheap coil for this detector. It came with a coil that is over 12" in diameter.
Reg
I purchased a Garrett BFO, large box, and when I got it, it wouldn't work. In my case the transistor that is the transmit oscillator was bad. I replaced it and now the detector works fine. Unfortunately, this isn't something that can easily be tested except to make sure the signal isn't there and I used a scope to determine that. I used a simple cheap PNP general purpose transistor.
I also checked to see if I could hear a squeal when I held a am radio in the middle of the coil. When bad, I couldn't hear anything reliable, but once it was fixed, the signal heard in the radio was quite distinct. I don't know the exact frequency but on this cheap hand held radio, the signal was somewhere between 13 and 16 on the am dial.
Now, I need to find a small cheap coil for this detector. It came with a coil that is over 12" in diameter.
Reg
Hello Reg,
Good to see you repaired the BFO, that's the risk we take buying an old detector. Sometimes they are mint condition but non operational or the opposite really beat up yet operate like a champ.
Can you post a picture of your Garrett BFO, model type etc that may give us an idea which smaller coil you need.
I always thought all Garrett BFO models used the same coils, boy was I wrong based from my Garrett BFO collection at least three BFO coils are different. Certain coils will only work with a particular model, be careful when you search for a coil.
What I can do is let you borrow a few, the smaller ones and hang onto the one that works. We can figure out something later, the main thing is you get the right coil.
Still use them every chance I get, recently changed the handle setup on my favorite one and added an arm rest. This is by far my best Garrett BFO drift free model I've ever owned, operates so smooth especially in tot lots. Will post a quick pic, Extreamly well balanced.
Pm me your mailing address, I'll send you a few smaller coils select the one that works and mail back the rest.
Paul (Ca)
Good to see you repaired the BFO, that's the risk we take buying an old detector. Sometimes they are mint condition but non operational or the opposite really beat up yet operate like a champ.
Can you post a picture of your Garrett BFO, model type etc that may give us an idea which smaller coil you need.
I always thought all Garrett BFO models used the same coils, boy was I wrong based from my Garrett BFO collection at least three BFO coils are different. Certain coils will only work with a particular model, be careful when you search for a coil.
What I can do is let you borrow a few, the smaller ones and hang onto the one that works. We can figure out something later, the main thing is you get the right coil.
Still use them every chance I get, recently changed the handle setup on my favorite one and added an arm rest. This is by far my best Garrett BFO drift free model I've ever owned, operates so smooth especially in tot lots. Will post a quick pic, Extreamly well balanced.
Pm me your mailing address, I'll send you a few smaller coils select the one that works and mail back the rest.
Paul (Ca)
Hi Paul,
Good to hear from you again. My Garret is like yours, a large master hunter type box that has the name Treasure Hunter on the side. I can post a pic but they all look alike. It is not the switchable model so it doesn't have the switch that allows one to switch between two coil sizes.
I found that this unit has a cap inside the connector. I suspect they use a cap to get them in the proper frequency range. That is probably the big difference.
As for taking chances, I bought three BFO's, two PNI units and this Garrett. None worked but all were easily fixed.
I am thinking seriously putting a Beachscan board in one of the PNI units just for fun. I think it would be fun to have an old BFO housing used as a PI.
On the other BFO, I might add a disc feature. I have an idea that might work and I need to try it when time permits.
Right now, I am working on some mods to the TDI and a GS 5. I have one GS 5 modded and boy what a difference in sensitivity but more importantly, what a difference in noise. This unit is super quiet even at the high gain. Now, I need to get a couple more going. I have two promised out and maybe a third to go to the factory.
My other project has to do with the TDI but I can't say much more at this time. All these projects have priority.
Reg
Good to hear from you again. My Garret is like yours, a large master hunter type box that has the name Treasure Hunter on the side. I can post a pic but they all look alike. It is not the switchable model so it doesn't have the switch that allows one to switch between two coil sizes.
I found that this unit has a cap inside the connector. I suspect they use a cap to get them in the proper frequency range. That is probably the big difference.
As for taking chances, I bought three BFO's, two PNI units and this Garrett. None worked but all were easily fixed.
I am thinking seriously putting a Beachscan board in one of the PNI units just for fun. I think it would be fun to have an old BFO housing used as a PI.
On the other BFO, I might add a disc feature. I have an idea that might work and I need to try it when time permits.
Right now, I am working on some mods to the TDI and a GS 5. I have one GS 5 modded and boy what a difference in sensitivity but more importantly, what a difference in noise. This unit is super quiet even at the high gain. Now, I need to get a couple more going. I have two promised out and maybe a third to go to the factory.
My other project has to do with the TDI but I can't say much more at this time. All these projects have priority.
Reg
Thanks Reg for sharing some of the interesting projects you have going, I know you have always been a great contributor for the GS 5 and now the TDI we appreciate the hard work and effort you continuisly put into the PI sector.
The information you gave on your BFO not having the coil selector switch narrows down the coil you need, pretty sure which one you need now but to play it safe will enclose two others. All three are the 5.5" inch coils, but the one I feel will work with your model is the latest BFO coil which helps with drift.
If you ever finsh the BFO discrimination feature and the Garrett BFO beachscan post some pics, with the right pi coil it will still appear to be a BFO only in disguise.
Below is a quick pic of my Garrett BFO collection, Several of the earliest 1960's models to several of the latest BFO models most of these were Allan Cannons personal machines. Some of the coils are one of a kind, prototypes for Allan actually one of the BFO models is a prototype made for Allan.
Take care,
Paul (Ca)
The information you gave on your BFO not having the coil selector switch narrows down the coil you need, pretty sure which one you need now but to play it safe will enclose two others. All three are the 5.5" inch coils, but the one I feel will work with your model is the latest BFO coil which helps with drift.
If you ever finsh the BFO discrimination feature and the Garrett BFO beachscan post some pics, with the right pi coil it will still appear to be a BFO only in disguise.
Below is a quick pic of my Garrett BFO collection, Several of the earliest 1960's models to several of the latest BFO models most of these were Allan Cannons personal machines. Some of the coils are one of a kind, prototypes for Allan actually one of the BFO models is a prototype made for Allan.
Take care,
Paul (Ca)
Sorry I haven't gotten back to anybody, have had some family problems I need to deal with, haven't looked into my BFO yet. One thing I do know is after using my AT Pro and Safari I sure miss the superb pinpointing of the Garrett dual coil system!! I wonder why no manufacturers aren't making dual coil machines?? Too expensive??
Yeah Reg, my buddy with a slightly newer Garrett BFO had his oscillators replaced and his machine now works once more. I need to get through some of the responsibilities I am faced with now and will get back to getting the oldie but goodie back on line. Where did you get your new oscillator from?? Funny about the radio test, I used to hear police car transmissions through my headphones while hunting.
Yeah Reg, my buddy with a slightly newer Garrett BFO had his oscillators replaced and his machine now works once more. I need to get through some of the responsibilities I am faced with now and will get back to getting the oldie but goodie back on line. Where did you get your new oscillator from?? Funny about the radio test, I used to hear police car transmissions through my headphones while hunting.
Ed in SoDak
Member
Transistor oscillators are made up of an inductor or coil, a capacitor and a transistor. Usually there's other parts to make it all work, but that's the basics. In a BFO, two oscillators are tuned to almost the same frequency. they are offset in frequency so you hear the combination of them, or beat frequency.
One of the inductors is the search coil, the other inductor is inside the box.
Many modern digital multimeters (DMM) can read transistors and capacitors as well as resistance and voltage, etc. Testing capacitors is iffy, because they really need to be tested for leakage using the frequency at which the circuit operates. Most of the easy tests that a DMM will perform are at DC, so while they can indicate problems, they won't find all of the bad caps you come across.
You can read an electrolytic capacitor for simple DC resistance with a DMM. It will start out at a low Ohms reading and this will climb through several ranges on your meter. Eventually it will top out and hold some reading. The higher this is, the better, generally speaking. A very low reading that does not rise is probably shorted. One that has essentially no reading may be open, but not always. Swap the meter probes positive and negative, and the capacitor will discharge and then recharge and once again rise in resistance as it charges up again.
The other common test is for capacitance in microfarads (uf). Not all meters have this function. Most electrolytics have a broad range of acceptable values, so don't expect a "10 uf" cap to be exactly that, but if it's way off, that indicates a weak cap.
All this can be fun, but new caps are so cheap, it's almost as easy to simply replace them as to trust any tests you might try. At least one lead should be unsoldered to test accurately, so just remove and replace any suspect caps. If there's a lot of them, the tests might help narrow it down to the few bad ones, but you may have to repeat the process again later if you don't change out all of them. You also have to be careful not to create new problems when you do a lot of wholesale parts changing, so it's good to test along the way to see if it got fixed or became worse due to an error creeping in.
Sometimes caps will bulge or actually spew their waxy contents, but not always in the low-voltage circuits. You might see discolored or burnt parts, bad solder connections or physical breaks or it all may look just fine. But often close inspection can reveal the problem.
You can read the battery voltage with the unit turned off and then on. If the voltage really drops when turned on, that may indicate a shorted part. Usually the voltage should drop a little, just not too much. If it doesn't change at all when turned on and off, that may indicate a bad wire, switch, connector or blown part.
Transistors can fail either way, shorted or open. They can be tested like two back-to-back diodes or your meter may have an HFE test.
Mica "disc" caps are hard to test, but fortunately are usually still good. Don't just assume they are good, however. Resistors also change in value and can go open. Battery corrosion can travel a long ways up wires to other parts. Dirty controls and switches has already been mentioned, but don't forget the coil cable and coil itself as they can fail, too.
Play with your meter on known "good" parts to see what readings to expect. Sometimes you can just probe around and visually inspect things without having to unsolder parts. Take good closeup pics or draw sketches to show where wires go and how parts you remove are oriented for polarity, etc. Tiny wires break off as you move things around and without the pics or diagrams, you'll never know where they came from.
Don't wade in too deep to where it's too much of a mess for someone with more experience to be able to figure out the original problem, let alone any new ones you've accidentally created.
To become familiar with the techniques, you can try them out on some broken old radio instead of your detector. This is how I learned, and from reading the old hobby electronics magazines of the 1960's and '70s.
-Ed
One of the inductors is the search coil, the other inductor is inside the box.
Many modern digital multimeters (DMM) can read transistors and capacitors as well as resistance and voltage, etc. Testing capacitors is iffy, because they really need to be tested for leakage using the frequency at which the circuit operates. Most of the easy tests that a DMM will perform are at DC, so while they can indicate problems, they won't find all of the bad caps you come across.
You can read an electrolytic capacitor for simple DC resistance with a DMM. It will start out at a low Ohms reading and this will climb through several ranges on your meter. Eventually it will top out and hold some reading. The higher this is, the better, generally speaking. A very low reading that does not rise is probably shorted. One that has essentially no reading may be open, but not always. Swap the meter probes positive and negative, and the capacitor will discharge and then recharge and once again rise in resistance as it charges up again.
The other common test is for capacitance in microfarads (uf). Not all meters have this function. Most electrolytics have a broad range of acceptable values, so don't expect a "10 uf" cap to be exactly that, but if it's way off, that indicates a weak cap.
All this can be fun, but new caps are so cheap, it's almost as easy to simply replace them as to trust any tests you might try. At least one lead should be unsoldered to test accurately, so just remove and replace any suspect caps. If there's a lot of them, the tests might help narrow it down to the few bad ones, but you may have to repeat the process again later if you don't change out all of them. You also have to be careful not to create new problems when you do a lot of wholesale parts changing, so it's good to test along the way to see if it got fixed or became worse due to an error creeping in.
Sometimes caps will bulge or actually spew their waxy contents, but not always in the low-voltage circuits. You might see discolored or burnt parts, bad solder connections or physical breaks or it all may look just fine. But often close inspection can reveal the problem.
You can read the battery voltage with the unit turned off and then on. If the voltage really drops when turned on, that may indicate a shorted part. Usually the voltage should drop a little, just not too much. If it doesn't change at all when turned on and off, that may indicate a bad wire, switch, connector or blown part.
Transistors can fail either way, shorted or open. They can be tested like two back-to-back diodes or your meter may have an HFE test.
Mica "disc" caps are hard to test, but fortunately are usually still good. Don't just assume they are good, however. Resistors also change in value and can go open. Battery corrosion can travel a long ways up wires to other parts. Dirty controls and switches has already been mentioned, but don't forget the coil cable and coil itself as they can fail, too.
Play with your meter on known "good" parts to see what readings to expect. Sometimes you can just probe around and visually inspect things without having to unsolder parts. Take good closeup pics or draw sketches to show where wires go and how parts you remove are oriented for polarity, etc. Tiny wires break off as you move things around and without the pics or diagrams, you'll never know where they came from.
Don't wade in too deep to where it's too much of a mess for someone with more experience to be able to figure out the original problem, let alone any new ones you've accidentally created.
To become familiar with the techniques, you can try them out on some broken old radio instead of your detector. This is how I learned, and from reading the old hobby electronics magazines of the 1960's and '70s.
-Ed
Ed in SoDak
Member
But wait, there's more! 
If you want to play with a BFO detector, they are actually very simple circuits to build from scratch. Several designs can be found on the web and the parts are inexpensive. Coils are one simple winding and can be almost any diameter. I made a BFO pinpointer using as a tiny coil a small inductor removed from some old TV or radio.
BFO detectors are useful for testing suspect stony meteorites since they can read both the iron content or the "mineral" portion that causes a negative response opposite to that of metal.
-Ed
If you want to play with a BFO detector, they are actually very simple circuits to build from scratch. Several designs can be found on the web and the parts are inexpensive. Coils are one simple winding and can be almost any diameter. I made a BFO pinpointer using as a tiny coil a small inductor removed from some old TV or radio.
BFO detectors are useful for testing suspect stony meteorites since they can read both the iron content or the "mineral" portion that causes a negative response opposite to that of metal.
-Ed