Products > Test Equipment
LeCroy WaveSurfer 24MXs-B Motherboard
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TheBay:

--- Quote from: tppc on May 08, 2022, 09:28:49 pm ---some of the mosfets are not even accessible with standard test leads. (maybe with miniature test hooks)

As mentionned, I measured a suspicious 8 Ohms across an electrolytic cap (even with the cap removed)
The problem is that I have no idea of what supply voltage it should be.

No idea either of what components are supplied by this rail.
Maybe tens of them. Which one of them measures 8 ohms? No idea.  :-//

--- End quote ---

That could be a capacitor across a voltage rail and why I said check the ceramic caps and mosfets as there might be something gone s/c across the same rail.
tppc:

--- Quote from: TheBay on May 08, 2022, 09:22:42 pm ---Also, depending on the configuration of that board and/or BIOS settings it might not display anything on the external VGA connector.
If you haven't already tried it might be worth removing the scope board off the motherboard to test it.

--- End quote ---
Yes, I tried with the mobo out of the scope,
-PC104 removed,
- mobo powered with external ATX PSU (started by shorting green wire on the ATX connecor)
- external VGA monitor connected.
(also tried with the internal display)
Black screen, nothing, not even a cursor.

I did not test the tantalums yet, but thanks for the advice, I will test them all. :-+
free_electron:
https://www.ebay.com/itm/362087872172
TheBay:

--- Quote from: tppc on May 08, 2022, 09:43:53 pm ---
--- Quote from: TheBay on May 08, 2022, 09:22:42 pm ---Also, depending on the configuration of that board and/or BIOS settings it might not display anything on the external VGA connector.
If you haven't already tried it might be worth removing the scope board off the motherboard to test it.

--- End quote ---
Yes, I tried with the mobo out of the scope,
-PC1014 removed,
- mobo powered with external ATX PSU (started by shorting green wire on the ATX connecor)
- external VGA monitor connected.
(also tried with the internal display)
Black screen, nothing, not even a cursor.

I did not test the tantalums yet, but thanks for the advice, I will test them all. :-+

--- End quote ---

Did you try clearing the BIOS, as it might be set to the internal display, also plug in a PS/2 keyboard and see if the Num/caps/scroll lock LED's flash on and off when it powers up and if the num lock works on the keyboard as that will give you an idea if anything has initiated.
Martin72:

--- Quote from: tppc on May 08, 2022, 09:17:11 pm ---Much too good for me, will take me ages to read the manual  :-DD

--- End quote ---

Duh, that is what I would call a real OEM board... :P
You won´t get an substitute except from lecroy itself.


--- Quote --- I measured a suspicious 8 Ohms across an electrolytic cap (even with the cap removed)
--- End quote ---

Is it a constant value ?
Minus of the cap is connected to common GND ?
Then you can measure the ATX connector against GND, maybe you find the 8 Ohms on one of the pins.
Additional:
Take off CPU and RAM and measure the suspicious points again...
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