Garrett (pulse) XL 500

[ripsdevala]

My setup


79L05 out 7.4v
78L05 out 12.5 v
I use 12v battery
I think its wrong.....

[reptooyep]

The MPSA13 is a darlington transistor. It's equivalent to BC517 or 2n6426.
You can check for equivalent here :http://alltransistors.com/crsearch.p...fe=5&caps=TO92
For your measurement, did you take the battery + as ground ? This MD has a strange power supply, the GND is the + battery, the charge pump generate +6.5v at the input of 7805.

[ripsdevala]

What??? What ever...let me try your methods

[ripsdevala]

You are right.... 79L05 out -5v, 7805 out 0v with + batt as ground test, should i put all the ic's?
Btw i cant find DR 100uh i made myself with ferrite rod with 100uh, is that okay?

[reptooyep]

The charge pump is made of a 555, 2 transistors and the 100uf you hasked before for value.
This should give a 6.5v at the input of the 78l05. You should have +5v at the output of 78l05.
All measurement should be done with the minus wire of your multimeter plug on the + battery which is a floating ground.

[reptooyep]

Btw i cant find DR 100uh i made myself with ferrite rod with 100uh, is that okay?

The inductance value is not so important, On other detectors, some version have one, some don't.
Maybe someone could explain this inductor need ? Your ferrite will work just perfectly.
I had a 68µH inductor, i added 10 turns with a piece of wire and it's fine too.

[ripsdevala]

Unfortunetly...nope, its not working, no sound at all, after put all the ic 79l05 out -1v 79l05 12v.... Any clue?

[reptooyep]

Ok, I will do it tomorrow.

Hi Fred,
i made few measurements this morning on the 4538 ICs.
On the first one, I have two output signals :
Pin 10 : Constant pulse (i did not measure the length)
Pin 11 and 6 : Variable pulse from 62µs (pot minus) to 18µs (pot max)

But on the second 4538, i have two constant pulse on the output when i act on the disc pot. I don't realy understand the second 4538 function.

[reptooyep]

Unfortunetly...nope, its not working, no sound at all, after put all the ic 79l05 out -1v 79l05 12v.... Any clue?

[ATTACH]37092[/ATTACH]

Your second 4538 IC is reversed. Try to take it out and recheck the voltages. If you have recover the good +-5v, just put a new 4538 in place.

[ripsdevala]

Your second 4538 IC is reversed. Try to take it out and recheck the voltages. If you have recover the good +-5v, just put a new 4538 in place.

Miss that one....okay i got this
79 -5v (+ probe ground), 7v with minus battery as ground
78 12v
2nd 4538
pin
1. 7.14v
2. 12v
3. 12.1v
4. 7.1v
5. 7.2
6. 7.1
7. 12v
8. 7v
9. 12v
10. 7v
11. 7.4v
12. 7v
13. 12v
14. 12v
15. 7v
16. 12v
With black probe on minus battery, in plus will different

[blobber]

Okay I also made some measurements, yesterday they was not correct, because the battery was empty.
Yes Arief, be careful with power supply, first you have to get the correct value +5V
after charging pump 555 and the two transistors!! Do not put any other IC in your board,
before you check all IC sockets, they must have the proper power supply.

[blobber]

[ripsdevala]

Did blow all the ic? The input of 78L05 is 12v output is same, is it dead?

[blobber]

That is possible, with too much power supply.

Sorry friends, I found a mistake in my layout file.
I was thinking about the wrong value in the picture from reptooyep, around LM324.
Please try to change the connection!
I will look further for other faults of course...sorry!

[ripsdevala]

That is possible, with too much power supply.

Sorry friends, I found a mistake in my layout file.
I was thinking about the wrong value in the picture from reptooyep, around LM324.
Please try to change the connection!
I will look further for other faults of course...sorry!

[ATTACH]37110[/ATTACH]