Sniffer xr71 / delta pulse version

[keith777]

Hi 6666

i would sell it but i would rather just post within the UK though.

[6666]

Hi 6666

i would sell it but i would rather just post within the UK though.

ok

[qute1]

Did you sell it ? the chance? if not i am uk and interested? also have not knob action on zr71 works on auto but manual is flunted.

[dbanner]

anyone any ideas on what i can do to sort the issues out with the board before it ends up in the bin etc.
or has anyone a working board that they could sell to replace this one?

What IC used for lf357 some are fake.

[kt315]

opamp tester pcb will be checked in 2-3 day. i have bought party of lf357 and if they work i will give a link on the seller.

[dbanner]

They may test ok on tester circuit, this don't mean that they are original part. They could be dual op amp, yes, but not original LF357N. This is why circuit above have poor sensitivity, maybe.

[dbanner]

Also coil and damping resistor together with pulse width and pps are critical for good operation.

[kt315]

for the checking only i use tl081 i find them in trash boards. dp has to work with it.
but speed of tl081 is not so hight and better to use lf357. in part list i did acumulate all possible substitutions
learned datasheets.

[kt315]

Also coil and damping resistor together with pulse width and pps are critical for good operation.

not, no so critical for DP. original DP schematic has damping resistor 2k2. DP works with big delay - from 40usec.
in reality i set a pot on 110-120. for this value damping resistor is not critical.

[dbanner]

Above I stated dual op amp, I meant to say single op amp, of course lf357 and tl081 are single.

[dbanner]

not, no so critical for DP. original DP schematic has damping resistor 2k2. DP works with big delay - from 40usec.
in reality i set a pot on 110-120. for this value damping resistor is not critical.

Yes, yes of course. You are very correct. I had used ne5534 on one of my detectors( not Delta) and it was fake component. The detector had very poor detection range. When I changed to different chip(brand) ne5534, then it worked beautifully. There are many fake chips out there, believe me.

[keith777]

Did you sell it ? the chance? if not i am uk and interested? also have not knob action on zr71 works on auto but manual is flunted.

Hi qute1.

i still have the chance machine. if you or still interested in it send me a PM.......