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Trasistor Cruve tracer + Hameg 1004-3 XY weirdness
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duak:
I would check the following:

One of the solder joints of the output connector may be bad.

Does the oscilloscope have a bandwidth limit control that reduces the bandwidth of the input channels?  I couldn't see one on the sales sheet from Hameg.  If there is one, does it make a difference when activated?

The current sense signal (CH2) will be of small amplitude.  I suggest getting a proper shielded cable with the correct connectors.  A 10:1 probe will definitely add noise.

There are some design features in the schematic from the other link that I don't understand.  However, I don't want to comment until the above things have been tried.
TERRA Operative:

--- Quote from: duak on October 15, 2019, 07:15:41 pm ---The current sense signal (CH2) will be of small amplitude.  I suggest getting a proper shielded cable with the correct connectors.  A 10:1 probe will definitely add noise.

--- End quote ---

This could be a thing.
For my unit, I have shielded cables from the X and Y outputs on the PCB to the front panel BNC jacks, then standard BNC cables directly to the scope inputs, so it's shielded and 1:1 all the way on both channels.
AngraMelo:

--- Quote from: duak on October 15, 2019, 07:15:41 pm ---I would check the following:

One of the solder joints of the output connector may be bad.

Does the oscilloscope have a bandwidth limit control that reduces the bandwidth of the input channels?  I couldn't see one on the sales sheet from Hameg.  If there is one, does it make a difference when activated?

The current sense signal (CH2) will be of small amplitude.  I suggest getting a proper shielded cable with the correct connectors.  A 10:1 probe will definitely add noise.

There are some design features in the schematic from the other link that I don't understand.  However, I don't want to comment until the above things have been tried.

--- End quote ---

Until now, all my tests were done either with a BNC>banana cable or the scope probes that are all 10:1. Im just finishing the enclosure (actually it is finished, it's the transformer that is taking some time to arrive) and during the assembly process I made sure to use coax from the board to the bnc connectors and Im making provisions to make a very small BNC>BNC cable.

The Hameg has no bandwidth limit but that is an interesting thought. Maybe the 2 Channels dont have the same bandwidth? so when I invert inputs (YX instead of XY) I get a clear picture? Or somehow the XY mode limits the bandwidth of one channel but not the other?

What do you guys suggest about the transistor connections? Should I run a small wire with a croc tip to hook the transistors up? would that be horrible?
Also, just ordered some more beads for the cables, Im going to load those suckers up with ferrite.
AngraMelo:

--- Quote from: TERRA Operative on October 15, 2019, 10:38:35 pm ---
--- Quote from: duak on October 15, 2019, 07:15:41 pm ---The current sense signal (CH2) will be of small amplitude.  I suggest getting a proper shielded cable with the correct connectors.  A 10:1 probe will definitely add noise.

--- End quote ---

This could be a thing.
For my unit, I have shielded cables from the X and Y outputs on the PCB to the front panel BNC jacks, then standard BNC cables directly to the scope inputs, so it's shielded and 1:1 all the way on both channels.

--- End quote ---

My order will probably be here the beginning of next week. I order some BNC connectors to make a very small cable. Also ordered some more ferrite beads for the cables.

TERRA Operative:
I have 10cm leads from the PCB to binding posts on the front panel, then I use 10cm banana to test hook leads to attach the transistor etc.

As long as I keep the test leads spaced apart, I get no issues at all.
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