Garrett (pulse) XL 500

[blobber]

I'am sorry that's happens.
My crazy hand drawn layout file from 2004 is correct.
But while redrawing in layout5, I made this mistake....maybe even more...so I have to work now.

[ripsdevala]

Its ok mr.fred... just cut and make a jumper, its already done. Now lets test 5v on 78

[ripsdevala]

Already change 78L05, same problem, or i have two dead 78??? Or my Dmm is crazy


Pick 78, still have 12v...short!!??

Nothing is short.... ???

[blobber]

What do you have output 555 pin 3 charging pump? Look at my picture from #101!

[ripsdevala]

What do you have output 555 pin 3 charging pump? Look at my picture from #101!

Right 555 pin 3 0v
Left 555 pin 3 12v, i think this is the charging pump, sorry not looking the scheme

All ic's is omit

If i put right 555 the output is 5.7v
Left 555 out pin3 12v

[blobber]

Please look always in the schematic, when you make measurements!
Well, in the pcb on the left side the 555 pin 3 should have around 400Hz, this oscillator provides the signal for your coil, the 4538 and the receiver.
The 555 pin3 on the right side in the pcb should have around 65 kHz 10V p-p, this oscillator provides the signal for the charging pump to get +5V.


Again, do not put any other IC in the socket, before you sure, to have the proper power supply for the IC's.

[ripsdevala]

Ok mr.fred, I will learn from what i got. I should get 5v and -5v right?, when i pick all the ic's and omit 78L05 i stil get 12v, is this normal or it should get 0v.

[blobber]

12 V in the output 555 pin 3 is too much. Check it with oscilloscope! Which frequency you have there?
Maybe your 555 is already burned.

[reptooyep]

You should take off the 7805 and check resistance between the output and gnd.
I burn 2X 78l05 cause TO92 packages are not strong at all...
Without an oscilloscope, you'll have hard time troubleshooting

Fred, now, everything is about to work... the output 14 of the 324 react with target.
I still have no sound. I put a 47ohm in serial with the HP (8ohm) to avoid too much current
In the T7 (BC517). This T can have 0,4A, so, i fix it to 0,16...
I'll check that sound problem tonight.

[ripsdevala]

Lets use the scope then...

[blobber]

You should take off the 7805 and check resistance between the output and gnd.
I burn 2X 78l05 cause TO92 packages are not strong at all...
Without an oscilloscope, you'll have hard time troubleshooting

Fred, now, everything is about to work... the output 14 of the 324 react with target.
I still have no sound. I put a 47ohm in serial with the HP (8ohm) to avoid too much current
In the T7 (BC517). This T can have 0,4A, so, i fix it to 0,16...
I'll check that sound problem tonight.

Good to hear that, well done!
Aha..I remember also, I have burned some 7805 and also 7905, look my picture, in the board is still a selfmade clone of 7905, because there was no more to find in my workshop.
I remember also, that the unit only runs, as I had the MPSA 13.
Are you sure about replacment of him?

[ripsdevala]

I have put mpsa13 on it, omit from unused tgsl...

Pin 3 left 555 0.4hz

[ripsdevala]

After change 555 ic

78L05 Resistance test grond with output 3k

[reptooyep]

I have a set of transistors and it shows compatibility between bc517 and mpsa13.
I'll try to find others

[ripsdevala]

Reptooyep, do you have board pic?i like to compare it