Marauder-2. Delta Pulse. Troubleshooting.

[kt315]

hi guys,
i got a project back, for the troubleshooting. i will tell you step-by-step what i do.
first of all, pcb is soldered so masterly as i only wait from you. THE nice example that i expect to see from you.

http://www.geotech1.com/forums/album.php?albumid=83

[kt315]

desoldered HV diode and mosfet - its are OK. i will supply the board without them.
orientation of all micros is right.

[kt315]

desoldered C21. i had wrote that you have to mod only after (AFTER) you got all working and tested in field.
anotherway you do not hear the sound on turn ON and not able appreciate your pcb works good
or not.

http://www.geotech1.com/forums/album.php?albumid=83&attachmentid=39397

do not set C21 on pcb at first.

[kt315]

setted VT10 VT11 in inverted position (thanks to Toros). checked them and they are good.
will tune a indicator voltage threshold later (by R52 or R53).
i setted 100 Hz PPS.
i setted PULSE WIDTH to sure 110-120--450us range, decreased R4 to 6k2.

http://www.geotech1.com/forums/album.php?albumid=83&attachmentid=39396

[kt315]

100 Hz PPS

http://www.geotech1.com/forums/album.php?albumid=83&attachmentid=39398

[karim1980]

hi kt315
ici lf357n not original
I tried this version of ici (m54af LF357N) is fake ici . Coming from China or singapor

[kt315]

hello Karim, how do you determine that its are fake?

[karim1980]

i Buy them and try with delta pulse and felezjoo No sound comes out
with lf356n Works well

[kt315]

try another opamps too. i gave BOM file with all subs.

http://www.ebay.com/itm/2x-AD744KR-SOIC-to-DIP8-Precision-500-ns-Settling-BiFET-Op-Amp-AD744-/120903872761?hash=item1c266eb0f9:m:mS-4EGeeJjpa3FaJpJQHGFQ

[kt315]

DP_BOM.pdf

[kt315]

http://www.geotech1.com/forums/album.php?albumid=83&attachmentid=39435

check the sound... good, no problem here.

[kt315]

the sound i turn THRESHOLD

https://drive.google.com/drive/my-drive

[kt315]

desoldered C21. i had wrote that you have to mod only after (AFTER) you got all working and tested in field.
anotherway you do not hear the sound on turn ON and not able appreciate your pcb works good
or not.

http://www.geotech1.com/forums/album.php?albumid=83&attachmentid=39397

do not set C21 on pcb at first.

sorry, i mean C30 above. tantalum on bottom side. my mystake.

[kt315]

you are right Karim. problem was LF357. probably its really fake (((

[karim1980]

Yes my friend has tried this type and did not work with any device. This particular figure does not work (m54af LF357N)
Try any other type that will work : tl081-lf356n-lm318-ua741...