V-I Curve tracer / Component tester

[Veketti]

Dear All,

Does anyone know is there available ready made connection box that can be utilized with Oscilloscope and Waveform Generator to test components in PCBA directly? So basically a box which has lead for waveform generator, leads for oscilloscope channel 1 & 2 and probes for DUT. Also needed internal connection and the 10ohm resistor. This setup is easy to build on breadboard to test leaded diodes etc. but not applicable for testing components on pcb..

Thank you

[andrewtaylor]

The sophisticated ready Made Box ist Sold as e.g. Huntron TR. 1000 and 2000 Models. Clones from CN are available too.

The poor man soltuion ist called Octopus circuit, Google gives an Impression. Soldering the 6 components and Put in Box: ist No Rocket sciencen

[Smokey]

The sophisticated ready Made Box ist Sold as e.g. Huntron TR. 1000 and 2000 Models. Clones from CN are available too.

The poor man soltuion ist called Octopus circuit, Google gives an Impression. Soldering the 6 components and Put in Box: ist No Rocket sciencen

wow.  Huntron Tracker 2000s are over 1K on ebay.  for a thing with a CRT.

[timeandfrequency]

Hello Veketti,

Does anyone know is there available ready made connection box that can be utilized with Oscilloscope and Waveform Generator to test components in PCBA directly?

Ready made no, but a schematic to build it as DIY device  (see also the attached zip file) :
https://www.radiomuseum.org/images/schematic-medium/hameg_gmbh_frankfurt/component_tester_hz65_3_486692.png

The sophisticated ready Made Box ist Sold as e.g. Huntron TR. 1000 and 2000 Models. Clones from CN are available too.

The poor man soltuion ist called Octopus circuit, Google gives an Impression. Soldering the 6 components and Put in Box: ist No Rocket sciencen

wow.  Huntron Tracker 2000s are over 1K on ebay.  for a thing with a CRT.

Yes, unfortunately, their price skyrocketed these last years. But there's a reason beyond the basic 'vintage' effect.
The CRT version is plainly able to display some weird but meaningful oscillations showing variable (multiple) traces intensities. Also, interesting discontinuities (e.g. tunnel diode) are clearly visible.
An LCD display device is just inadequate to show such singularities.

[Smokey]

...
An LCD display device is just inadequate to show such singularities.

gotcha.  and vinyl sounds better too, right?

[timeandfrequency]

...
An LCD display device is just inadequate to show such singularities.

gotcha.  and vinyl sounds better too, right?

Did you have both versions (CRT and LCD) of the trackers in your hands for a faithful comparison ?

[kripton2035]

this is the low cost option, ready built.
https://www.aliexpress.com/item/1005007169046145.html

[Veketti]

this is the low cost option, ready built.
https://www.aliexpress.com/item/1005007169046145.html

Wow! Don't even need the waveform generator, just Oscilloscope. This is perfect and affordable price too. Ordered one of these, thanks!

I see maybe the CN clone is for example ASA Tracker-3000. Looks to have lots of features, but it aint cheap +500€/$ price range. Didn't find any review of that, but it's ok as it's bit too pricey for me.

I know those Huntrons, but agree with Smokey, that they're expensive for that kind of vintage devices. If it were 200$/€ I'd consider.

[RAPo]

There is a new version with built-in display ;-)

this is the low cost option, ready built.
https://www.aliexpress.com/item/1005007169046145.html

[kripton2035]

Nice, but it seems very new as I can't find any video online about it...

[timeandfrequency]

There is a new version with built-in display ;-)

The product page talks about one unique voltage range : 4V
Really ?
If correct, this would be a serious drawback.

this is the low cost option, ready built.
https://www.aliexpress.com/item/1005007169046145.html

I spotted a similar model about a year ago.
This one has four voltage ranges : 0.6,  4,  8 and 16 V, which is quite versatile.
However, higher voltages are sometimes useful for Zener and Transil tests and also to detect semiconductors that show up partial breakdown failures.

All these models feature an internal sine generator with selectable current limiting resistor.
The additional variable level synchronous pulse output, if available, is mainly used to test 3-legged semiconductors in off-circuit test mode.

[mawyatt]

Here's some links some may find interesting.

https://www.eevblog.com/forum/testgear/fooln-around-with-dso-awg/

https://www.eevblog.com/forum/projects/dso-awg-based-curve-tracer/

We haven't completed the above (yet), however should be an interesting project for someone with an interest.

Best

[Veketti]

I ordered the "professional" version which has four different test voltages. I assume it's safe to use the 4V for for 3.3V components as well? It seems these come without any instructions but there seems to be few instructional videos in YT, but unfortunately in Spanish and Russian. Fortunately English captions were available so that's pretty clear how it works.

But none of the videos were describing how to use the user: timeandfrequency mentioned pulse output (I think the lower right hand corner blue button in the picture). Can anyone decribe how that is used to test components?

[RAPo]

The blue connection and buttons are for testing two components at the same time.
First, set the parameters for one component, hooked up to red and connector black this is the reference component
Next, pick the component you want to test and connect it to the blue connector and the black connector just next to it.

Then press the A/B button.

This multiplexes the reading from the red and blue connection.
The right blue button regulates the speed of the multiplex.
Look at this to see the switching in progress.

I ordered the "professional" version which has four different test voltages. I assume it's safe to use the 4V for for 3.3V components as well? It seems these come without any instructions but there seems to be few instructional videos in YT, but unfortunately in Spanish and Russian. Fortunately English captions were available so that's pretty clear how it works.

But none of the videos were describing how to use the user: timeandfrequency mentioned pulse output (I think the lower right hand corner blue button in the picture). Can anyone decribe how that is used to test components?

[RAPo]

Yes really (my device just came in an hour ago) and yes a very serious drawback., 16V should be there.

The product page talks about one unique voltage range : 4V
Really ?
If correct, this would be a serious drawback.

[timeandfrequency]

Yes really (my device just came in an hour ago) and yes a very serious drawback., 16V should be there.

The product page talks about one unique voltage range : 4V
Really ?
If correct, this would be a serious drawback.

At least, the description matches with what you get

[Poroit]

This one came up on the Repair Forum...."What More Can I do"

[watchmaker]

this is the low cost option, ready built.
https://www.aliexpress.com/item/1005007169046145.html

Couple $30 multi voltage tracer to the SC02 https://www.aliexpress.us/item/3256805833382411.htm  and you have a decent workable low cost unit.

I have used the SC02 for a Thaikit w/Octopus but am relying on others about the V/I tracer itself.

[RAPo]

Well, maybe we should start tinkering.
The device has two 4.0V batteries.
And a LD1117AG voltage dropper.
If we can replace these to higher values there is some hope.

I was looking for the pins that send the signal to the display, in the hope of tapering them off to BNC so we can also look at it on a (analogue) scope.
Didn't find them, need some more time....

At least, the description matches with what you get

[RAPo]

Added to my own post:

A video using exactly this device in A/B mode is.

The blue connection and buttons are for testing two components at the same time.
First, set the parameters for one component, hooked up to red and connector black this is the reference component
Next, pick the component you want to test and connect it to the blue connector and the black connector just next to it.

Then press the A/B button.

This multiplexes the reading from the red and blue connection.
The right blue button regulates the speed of the multiplex.

[timeandfrequency]

Well, maybe we should start tinkering.
The device has two 4.0V batteries.
And a LD1117AG voltage dropper.
If we can replace these to higher values there is some hope.

Sure that it's worth improving this TE.
If you can raise the AC test voltage the TE provides at its outputs, you will also have to add some attenuation on the X axis channel of the display.
For these 'octopus' devices, the trace on the X axis (voltage axis) should always have the same width (which is close to the full screen width, or as wide as the graticule, if displayed). Of course, this is only true when there's no DUT connected to the output(s).


If there's enough room, try to add a DPDT switch, so you can select between two ranges : one circuit will change the feedback resistor of the LD1117AG. The second circuit  inserts an attenuator (= basic resistive divider) in the X channel measurement path. 


Update #1
If the batteries (Li-ion I assume) are close to empty, you will have just a bit more than 5 VDC in the 2S configuration.
I don't know if an in deep circuit analysis is feasible but as ultimate goal, it would be interesting to be able to separate the power supply of the sine generator (so that measurement voltage can be raised to 10 VACpeak or perhaps even 20 VACpeak by using a small booster) from the supply of the processing assembly (probably 3,3 VDC).

10 VACpeak  (= 20 VACpp) sine waveform output  is doable if the TL084 opamps are supplied with at least ± 15VDC (± 18VDC max).
For 20 VACpeak (= 40 VACpp) output, an additional high voltage opamp is required. The low values series resistors must also be replaced by parts with higher power dissipation.*

Update #2
We started a deeper analysis of the TE circuit below, so several sentences in this post are no longer valid :
- LD1117AG is a fixed value regulator : it's output voltage cannot be changed as easily as indicated here.
- Presumably, there's a boost regulator after the Li-Ion batteries. So even close to empty, there should be enough voltage for the downstream circuits.

[RAPo]

well, right now, the circuit is not working: pressing+keeping the on-button shows the LCD screen monetarily but with an off-scale low (in the sense of no green bars) bat. indicator. The battery themselves are full. I must have done something wrong/

[Veketti]

The blue connection and buttons are for testing two components at the same time.
First, set the parameters for one component, hooked up to red and connector black this is the reference component
Next, pick the component you want to test and connect it to the blue connector and the black connector just next to it.

Then press the A/B button.

This multiplexes the reading from the red and blue connection.
The right blue button regulates the speed of the multiplex.
Look at this to see the switching in progress.

Yes, I knew the A/B button but I meant this square wave button:

[Kean]

Yes, I knew the A/B button but I meant this square wave button:

The model RAPo bought was the one with the display which doesn't have that button.

It seems the label on the button translates as "pulse".  I suspect it changes the frequency at which it alternates between A & B measurements, which is what RAPo said.

The right blue button regulates the speed of the multiplex.

[timeandfrequency]

well, right now, the circuit is not working: pressing+keeping the on-button shows the LCD screen monetarily but with an off-scale low (in the sense of no green bars) bat. indicator. The battery themselves are full. I must have done something wrong/

Bummer, that's bad news.
Lets make some checks on the internal power supplies.

Remark #1 : As I don't know your level of knowledge in electronics, here are some guidelines. But if you're experienced, you might find the below advices as unecessary or overkill.

Remark #2 : If you want to start a repair action, consider creating a dedicated thread in the 'Repair' section of this forum.


At first glance, as I see no transformer on the PCB, I would say that all of the supplies should have the same GND.
But it seems also that each battery has its own set of wires.
So how does the PCB connect them together ? In // ? In series ? Or are they independant of each other ?
 
 I guess there are 4 regulators, but I can't read their markings :
- a) the LD1117AG you already mentionned; confirm the '50' voltage code  (meaning 5 VDC output)
- b) Just above the latter, the the part in the SOT223-4 package is likely also a linear regulator
- c) Towards the bottom, there's a SO8 part just above the '330'  (33µH) inductor
- d) Top right, there's another regulator/charger near the '2R2' (2,2µH)  inductor

Identify each part, find their datasheets and check their output voltage.