Stunning 3000A, 2000A, 3000T power supply discovery - MUST READ IF YOU HAVE ONE

[EE-digger]

Reply #53 in this thread may be of interest to you:  https://www.eevblog.com/forum/repair/dso-x-3024a-power-supply-defect/50/

At 400k+ ohms, the startup voltage was 135 volts.  Perhaps not an issue for you but would be on 120v mains.

[EE-digger]

Another happy camper with a Murata PQC250-12 installed.

It took a few resistor moves to invert the remote on/off signal and it took a bit more doing to get rid of very annoying acoustic noise whether on or off.

Spoke with Murata and one of the posters and no one has had this problem.  I had it on the two supplies I tried.

It comes down mostly to one capacitor (ceramic, 10uF) that sounds like a dentist drill if you gently touch the top with tweezers.  My solution was to replace it with a Murata metal mounted cap of same value.  You can also get interposer caps.  I first made my own interposer before the Muratas arrived by simply mounting the cap piggyback on a 1 Mohm 1206 resistor.  I have to say that this was quite good.

If anyone want the on/off inversion info, I'll post it.

[Helix70]

Another happy camper with a Murata PQC250-12 installed.

It took a few resistor moves to invert the remote on/off signal and it took a bit more doing to get rid of very annoying acoustic noise whether on or off.

Spoke with Murata and one of the posters and no one has had this problem.  I had it on the two supplies I tried.

It comes down mostly to one capacitor (ceramic, 10uF) that sounds like a dentist drill if you gently touch the top with tweezers.  My solution was to replace it with a Murata metal mounted cap of same value.  You can also get interposer caps.  I first made my own interposer before the Muratas arrived by simply mounting the cap piggyback on a 1 Mohm 1206 resistor.  I have to say that this was quite good.

If anyone want the on/off inversion info, I'll post it.

Yes please, my MSOX3014T (early model) power supply just died (GE CCH0125F1-Z03A) and am researching the best replacement options. Having the correct switch position is important to me as it is a work scope and I don't want the risk assessment!

[djsb]

I have a Keysight MSO-X3054A. Is this scope affected by this and what should i be looking to replace in the power supply and with what? Thanks.