Older Compass 77b schematic

[Reg]

Hi All,

I was just wondering if anyone has the schematic for the old Compass 77b. I have one that doesn't work and would like to get it going myself if possible. Unfortunately, I dont' have time to try to reverse engineer it.

Since someone just happened to have the Judge 1 schematic, I guess I can hope someone has the 77b schematic.

If no one has the schematic, anyone have an idea of how close the Judge schematic is?

Thanks,

Reg

[kt315]

I found this via google. some good video of a collection. what can you say about 77B, 77 Automatic, 77 Auto Legend models? what is the best? what frequency they use? can you do a list on IC's from your detector PCB? is there quartz/quatzed generator on TX side, anything like to on CD40xx? photos of PCB will be meeting of All here plaudit, I believe.

http://www.thetreasuredepot.com/cgi-...g.pl?read=4110


Posted By: Doug in ILL. <Send E-Mail> (67.134.119.19

Date: Saturday, 5 August 2006, at 6:07 p.m.

I went and got a premium account at Photobucket.com That gives
access to downloading videos up to 10 min. long. I figure I will see how this works and if everything goes good I will be posting videos later of my hunting sites and the finds as they come out of the Ground.....SOUNDS EXCITING!! Got to love todays technology. The video your about to see is a TEST VIDEO just showing my detectors. It's a good start to some GREAT Future Posting.....

http://s65.photobucket.com/albums/h218/duggr/?action=view&current=Picture047.flv

[Unregistered]

You may want to check with Keith at www.broken detector.com and see if he has a schem on it, he also works on Compasses.
Steve(in MS)

[Unregistered]

The 77B,77 auto and Compass auto legend are 100KHZ units. They are the best of the Compass TR units. They don't go as deep as newer VLF's designs and have no disc except they do not react to small nails, they are the best units to use in highly iron nail areas and have great see through ability. I don't know where to find any schematics on them other than the maybe the website above.
Steve(in MS)

[Esteban]

What year the Compass series?

[kt315]

is it a static (non-motion) detector?

[Reg]

Hi All,

Thanks for the replies.

I don't know how old the 77 I have is, but it is quite old. My guess is it is one of the earlier versions. It is not one of the later ones for sure.

The unit really isn't worth sending in to get fixed, so I guess I will just tinker with it in my spare time. Hopefully, a schematic will show up later.

Thanks,

Reg

[Unregistered]

I have an older 77B automatic

Hello Reg,

I don't have the schematics to the 77B automatic but do have a good working one. If you can't find the schematics and would like to compare mine against yours I can sent you my 77, You can send it back once you figure out the problem with yours.

HH, Paul (Ca)

[Mrand]

Please, Compass 77 Automatic Tuning.
Mrand

[Esteban]

Mrand, thanks.

The anotations on the IC aren't very clear, but I can read these:

- ICA1 = 741

- ICA2 = 308

- ICA3 = 1458

- ICA4 = 1458

[Reg]

Hi All,

Once again, I want to thank all of you who provided information. Hopefully, I will be able to fix the unit now.

Thanks again,

Reg

[Mrand]

ICA2 is 3080 not 308.
Mrand

[Esteban]

Thanks, you're right!

[Reg]

Just wanted to say that the old Compass 77b is up and running now. Turned out to be a bad opamp.

Thanks again for all the info.

Reg

[Geo]

Hi all. A friend gave me a compass 77b to repair it. It has very low sensitivity and the tune knob dont work.Does anyone can tell me what about the voltage at pin 2 and 3 of ica1, and pin6 of ICA2. ICA1 writes to be a CA3094.... may i change it with a 741?
It is so small and easy detector but it generate me a lot of problems grrrr#$%^&*
Regards