LeCroy 7100 repair-won't turn on-"relay ?" clicking

[itkruglak]

Hi, I just picked up a LeCroy 7100 in great shape--but not working.  When ON button is pushed, I hear a relay clicking sound. It could be the HDD trying to initialize--or something else.  It could be a PS problem-this is a complex beast and I would be grateful to anyone who has repaired this model scope and has suggestions.

Thanks!
Ivan

[DaJMasta]

Hard drives can click, but I wouldn't expect it immediately at power on.  The unit I've heard an immediate, steady clicking noise like a relay had a bad power supply, and yes, it's both large and sandwiched in an inconvenient place.

I'd recommend checking that cables are secure and whatnot first, then probably unplug some subassemblies and power it on to see if something is shorting it, but I believe it could be the startup procedure for the PSU not completing or the acquisition board reading a bad voltage and telling it to shut down through an external (of the PSU) shutdown line.

[Alex_twn]

I recently acquired 3 Lecroy broken scopes (WR6100, WR6050, WP7000), I took my chance to "waste" ~500$ for the 3 but did not regret at all in the end.

First I fixed the WR6100 few weeks ago with a similar symptom.
With the main plugged you could hear a tic tic tic ... all the time and the problem was on the PSU.
Luckily I was able to find the schematics for the PSU but I don't believe it is the same as the WR7100 one.
The fault was on the primary, after the bridge rectifier, a switching transistor was not able to create the 15V needed due to 2 dry electrolytic capacitors with high ESR and 1 dead diode.
A 2$ fix.

The WR6050 was not starting the DSO application.
After a quick check I found out that the Intel motherboard was having 3x 3300uF/6.3V very dry and opening up at the top.
Another easy fix, with 3 new caps it started immediately and works perfectly like the WR6100.

The WP7000 was supposed to be broken, but it already start to show some good sign of life.
I will open it up and clean it so if I can help with the PSU let me know as it should be similar to your 7100.

Those scopes seems robust and when a fault happens, not too difficult to fix.
Considering the price I paid for the 3, I am quite happy with the deal !