Garrett (pulse) XL 500

[reptooyep]

7808 input 3.9v

Hi,
Too low output charge pump could have several reasons.
If your 200pf is good value, i would change the 2 transistors and the 2 diodes of the charge pump.
I'm sure you've already verify the capacitor's polarity..

[ripsdevala]

Hi,
Too low output charge pump could have several reasons.
If your 200pf is good value, i would change the 2 transistors and the 2 diodes of the charge pump.
I'm sure you've already verify the capacitor's polarity..

Hello,
220pf is good, i measure it before soldering, 2 transistor already change.
Let me try change diode....

[ripsdevala]

Reptooyep,

Geniuss....!! I found it to be 4v3 diode...... I think the seller give the wrong item, i will check the others 4148

[blobber]

Bottom
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Your bottom view is not so clear! Are you sure, that you have there no short circuit?

[ripsdevala]

Bottom
[ATTACH]37145[/ATTACH]
Your bottom view is not so clear! Are you sure, that you have there no short circuit?

Yes im sure, some pad s is less than 1mm to each other, very hard to see in picture.
Bc548 and 558 not hot anymore, but pin3 555 charge pump is 0v, not like yours 10v

[dbanner]

Just something I noticed earlier in the thread, the garret xl500 circuit which uses the LM324 is actually the Garrett xl200 p.i. I built this circuit and it performed very well. This circuit(xl200) operates at around 400pps whereas the xl500(the circuit using the 741 and lm358 operates at 110pps). The stock surf master pi operates at somewhere around 630pps.

[ripsdevala]

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.

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Measurement without 555 oscillator, -pole as gnd:
battery voltage -11.9v

555 pin 3 charging pump -6.4v

Oscillator 555 pin3 0v

collector T2 0v

output 709 pin 6 0v

4066 pin 13 0v

4066 pin5 0v

There is something wrong here....

[reptooyep]

Pole — as gnd ?
Is it a joke ?

You said without 555 oscillator but it has non sense, which one ?
Do you mean you have put all chips exept 555 ? It's not clear.
Without any chips, it's normal to have 0v output..

[ripsdevala]

Omg...sorry wrong writing, i mean +pole
Yes that only with 555 charge.

[reptooyep]

Could you please measure the power supply of the chips, now that you have -6.3 charge pump supply ?
GND (Still battery +) of NE555 (pulse generator) and pin 1 = -5v
GND and 4538 pins 8 and 12 = -5v
GND and LM324 pin 4 = +5v
GND and LM324 pin 11 = -5v
GND and LM709 pin 7 = +5v
GND and LM709 pin 4 = -5v

[mungos]

XL-500

I made this version of xl-500 and works fine. But my spool is not good and results are not excellent. You can compare the pcb-s because it has similarities .
garrett XL-500.zip

[ripsdevala]

Could you please measure the power supply of the chips, now that you have -6.3 charge pump supply ?
GND (Still battery +) of NE555 (pulse generator) and pin 1 = -5v
GND and 4538 pins 8 and 12 = -5v
GND and LM324 pin 4 = +5v
GND and LM324 pin 11 = -5v
GND and LM709 pin 7 = +5v
GND and LM709 pin 4 = -5v

Good morning all,

Yes, 555 pin3 charge pump (555 right side) -6.3v

NE555 (pulse generator) (left side 555) and pin 1 = -5v ok
GND and 4538 pins 8 and 12 = -5v ok
GND and LM324 pin 4 = +5v ok
GND and LM324 pin 11 = -5v ok
GND and LM709 pin 7 = +5v ok
GND and LM709 pin 4 = -5v ok

All okay....

[blobber]

I made this version of xl-500 and works fine. But my spool is not good and results are not excellent. You can compare the pcb-s because it has similarities .
[ATTACH]37152[/ATTACH][ATTACH]37153[/ATTACH]

I am glad, that someone else was also able to finish this project.
*could you please post some pictures of your board and your unit?
Which coil you are using?
How are your results?

[reptooyep]

All okay....

Glad to hear that.. what about the functionning ?

[Altair]

Are there somebody who have traced the control signals timing of the two sampling points?
I am studying the circuit with purpose to do some modifications; I found it very interesting!!!
Any help would be appreciated.