On second thought; the manual says it is an "auto-range" circuit, meaning it is supposed to boost at 110VAC and do nothing at 230AC. So seeing a wave at the orange wire when the input is 230vac may not be a good thing.
So stj is correct. I will just not install it. losing it a long time ago may have been a good thing.
thanks.

You should test it like I did as shown in the attached picture.
Using an isolated transformer, connect both lines, one to the blue and one to the yellow. Hook oscilloscope ground to the blue wire and the oscilloscope probe to the orange wire. At 230VAC, the line voltage is seen at the orange wire except in the sense that it is inverted in the sense when compared to the diode bridge current flow.
This defeats your theory that it is merely a switch at 110V.

When I said inverted in the sense when comparing to the diode bridge current flow, I will explain further;
When...

Merry Christmas Everyone. I have found out the answer and this is the only site where I shared the information.
The custom module is a Charge Voltage Booster/Balancing Circuit but I don’t think it is a PFC circuit though I don’t know the exact naming as it is a custom module.
The capacitors C1 and C2 are each charge/balance on alternative line voltage excursion of the AC wave.
The 3 wires are connected as follows;

Blue to E4
Yellow to E3
Orange to E6
See attachment.

If your module is damaged, here is how you can circumvent the circuit...

I dismantled the wires long time ago and can't even remember to install the component back the last time I repaired the power supply. Now can't remember where the wire goes though I found the component back recently [was shocked that I didn't install the component from old records of photo]. As can be seen in the pictures the wires is yellow, blue and orange in color.
I actually like the lecroy Oscilloscope, user friendly interface though very noisy but as close as to reality trace is what I can rely on.
Any chance you take a look at yours? [still with the adhesive wax in place ...

The Varistor and Diode assembly is shown in the picture attached. It is wrapped in masking tape and near to the fuse....

Lecroy power supply - this power supply is prone to failures. I have repaired mine a couple of times before. The problems with this power supply range from shorted out power mosfet, the green module pwm driver, aging EMI filter, shorted snubber etc.
I once dismantled a custom component that I cannot identify, no way of knowing if it was the cause, and thus I have no way of checking it. However the power supply can still power up and supply properly without this component.
This Component is not shown in the Schematic but apparently it is side piggy back mounted on the EMI filter as...

Thanks Lisa....

Hi everyone, I'm Armadillo from Singapore. I am an Electronic Hobbyist and I am able to repair most electronics. I also do programming in c/c++, embedded programming STM32, STM8, Atmel etc. I have most equipment from oscilloscopes many, spectrum analyser, logic analyser, GHz Freq Gen, Vect Analyser etc.
Badcaps has provided valuable information and had help me many times and this community is wonderful with many talented people. thank you all.

Re: New Members - please post your introductions here

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And BadCaps.Net caught my eyes and I have not seen cluttered advertisement as yet....