Opinion for an ESR meter before the garbage can!

[whiz115]

Hi! happy new year with lots of successful electronic projects for all!

In the attached pictures you can see the schematic and the pcb for an esr meter i've built few years ago
this thing....never worked as it should, it seems functional but the capacitance measurement always
shows CX ----

i tried alot to troubleshoot it....measured every component for broken joints changed most of the ICs
in case of a faulty one but still it can't perform any measurement.

i've spent alot of time and effort to build this device also the component cost wasn't exactly negligible
so now it ended up one step before i salvage it and throw it to the garbage can. :/

would you like to help me save it?

P.S original project was descussed in the following Russian site
**broken link removed**

 

[hyedenny]

I see a lot of potential solder-bridges, and the board is a bizarre layout.
Did you check with a scope to see if the timer section is working?

 

[KevinW]

This may or may not help.
https://www.mikrocontroller.net/attachment/164956/ttester_eng104k.pdf

 

[whiz115]

I see a lot of potential solder-bridges, and the board is a bizarre layout.
Did you check with a scope to see if the timer section is working?

checked once again for broken joints or bridges and seems fine.

currently i dont have a scope, only a frequency meter @10MHz is available
can you point where i should measure and what? thank you.

This may or may not help.
https://www.mikrocontroller.net/attachment/164956/ttester_eng104k.pdf

The pdf is so great and looks like it offers full support for somebody who wants to build
the instrument it describes.. but how exactly it can help me?

 

[schmitt trigger]

A PCB layout that simultaneously uses SMT components, no solder mask, and is intended for assembly by hobbyists, is a recipe for disaster.

I would check for solder bridges at every SMT component using a microscope. Usually, microscopic solder whiskers or remaining flux can cause enough leakage to cause circuit problems.

 

[whiz115]

ok i will check again and i'll let you know.

 

[whiz115]

There's a missing 100nF capacitor which i think it's not important,because
in the Russian site i've noticed some others they also skipped that cap, it's
underneath the micro controller next to the 22pF caps for the crystal.

other than that i can't find any problem in the smd side, since the device
turns on, how can we isolate the problem?

i'm uploading the pcb layout.

.

 

[whiz115]

Would you like to help me with that?

 

[whiz115]

guys nobody? is it that hard?...

 

[schmitt trigger]

I'm really sorry but.....
It is because you don't have the proper test equipment. A frequency meter is useless here.

And troubleshooting from a distance via a forum, it makes it even harder.

And without the ability to read Russian, it makes it impossible.

 

[whiz115]

I'm really sorry but.....
It is because you don't have the proper test equipment. A frequency meter is useless here.

it's quite hard for me to find an oscilloscope this period, are you sure it's the only way so i can fix
the esr meter?

And troubleshooting from a distance via a forum, it makes it even harder.

this is not serious obstacle, i've done it before, help others and also helped by others
to troubleshoot electronics. (only once years ago and only on this forum i had to send a
pcb to ericgibbs so he can see it from near and fix it). THANKS again ericgibbs!!
isn't he moderator anymore?? :S

And without the ability to read Russian, it makes it impossible.

also this one is not so much problem...i can't read Russian too, but
with google translator i could understand alot from that website.

 

[debe]

**broken link removed** For the price of these already assembled, why bother. I have 2 of these & they work great.

 

[whiz115]

**broken link removed** For the price of these already assembled, why bother. I have 2 of these & they work great.

the instrument i've built it's years ago and happens to be useful from time to time.
i must do something, it shouldn't go wasted forgotten in a drawer, this forum is the last resort.

 

[debe]

Un fortunately with electronics ive found theres so mutch progress that some times, its time to move on to something more modern & versatile.

 

[whiz115]

what do you mean "more modern" ? this is not a cell phone or a PC so i can upgrade.
it's a DIY instrument

I'm really sorry but.....
It is because you don't have the proper test equipment. A frequency meter is useless here.

rethinking what you told me, i don't understand why you find a scope so mandatory!
the waveform should be a square wave or something similar to that, what is
important it's if there is any oscillation...(since from what i know) these instruments
pass an ~100KHz to the capacitor under test, am i wrong on that?

the PIC microcontroller starts so i guess i don't need to measure if there's a 20MHz oscillation.

the ~100KHz test frequency should come out from the op-amp..right? if yes, where do i take
that measurement??

guys pls a little bit help i need.