Seeking Surf Pi Pro help,connected the battery backwards!

[sdesic]

you can use any above 500 Ohm if you use piezo

[sentella4d]

Hello sdesic;
I remembered that i had one TLC555CDR at home ,but in a 8-soic configuration instead of PDIP.I went ahead and adapted it temporarily by soldering 30 gauge enamel wire to the pins and I was able to mount it temporarily to the board in order to finish diagnosing the detector before my parts arrive.It was hard to solder and make it fit,but I made sure that there are no shorts or bad soldering joints.I found a 1000ohm resistor,and tested the 555 it is buzzing.THe 9640 is not overheating,it was at the beginning but i had a loose battery connection that was causing it apparently,it is fine now.I have a trimmer set at 3.1k(It has worked before as low as 2.3K). I never measured the impedance it is based on the estimate of the construction article,but the coil is extremely deep,stable and sensitive(I have used it for a few weeks)

Which pin is the base of mpsa13, C,B or E?

[sentella4d]

Dear sdesic;
I have no sound coming from either pin of MPSA13 with the utility

[sdesic]

B is base
try pin 11 of 4066 and 4093
also D3 both sides...

try waving (strong) magnet close to coil

[sdesic]

can you adjust tresh and delay ?
any changes ?

[sentella4d]

Dear sdesic;
I have sound on pin 11 of 4093,but nothing on pin 11 of 4066,D3 or b of MPSa13

[sdesic]

try waving (strong) magnet on coil

[sentella4d]

Hello sdesic;
Sorry I could not get back to you sooner. I tried waving a strong magnet in front of the coil but i got no response.

[sdesic]

Change MPSA13...

I will compare my surf pi pro when I get home.

[sentella4d]

Hello;
I went ahead an replaced MPSA13 but it did not work,no sound.I tried waving a magnet in front of the coil but it did not sound of either.

sentella4d

[sdesic]

If someone has any other idea please reply.

Probably will be... "You need oscilloscope to repair that"

[kt315]

I went ahead and disconnected the coil,and 9640 stopped heating up

first of all, you have to desolder 9640 and get the clear impulses at its gate pad. NOT DO ALL MEASUREMENTS WITH 9640 SOLDERED.

WITH UNWORKING IMPULSE PART OF SCHEMATIC 9640 WILL BE HEAT UP TO BURNT.

after that you have got all power supply voltages as normal solder it back and continue.

[sentella4d]

Hello kt315;
The 9640 is ok now,apparently I had a loose battery connection and a loose cap that was causing it to heat up. Afterwards I tested it following the procedure from this site: http://www.ehow.com/how_7683791_chec...osfet-dmm.html and it passed the test.Although a magnet provides no response,when i move the headphones close to the coil i get a faint buzzing sound on the headphones.

[sentella4d]

Hello Guys;
Does anybody else have any ideas as to what to check next?

P.S.lost the -5v again from the 7660 and i do not know why.I cannot find any cold joints.I changed the 5555 timer and the 7660s just in case again, but I still do not have -5v from pin 5,it currently reads .96v.I also changed both the 4093 and the 4066 but that did not help either. Any ideas?

Thanks,sentella4d

[sdesic]

If I was in your place I would make new one from 0
Problem is difficult to find...