Fixing the RF front end of a spectrum analyzer - Siglent SSA 3021X

[Mach1]

Hi EEVblog members,

A spectrum analyzer RF front end can be easily damaged caused by long standing, low-frequency harmonics contents. The wide use of motor drive and DC-DC converters makes it even easier to damage a spectrum analyzer if you are not being careful. I recently damaged and later fixed the front end of my Siglent SSA 3021X and recorded the process. For those who have suffered from similar problems and got frustrated by the cost and lead time of having the unit repaired, check out how to fix the RF front end of a spectrum analyzer.

For those who enjoy reading, check http://emccompliance.co.uk/fixing-and-protecting-the-rf-input-of-a-spectrum-analyzer


For those who enjoy watching, check

Happy fixing

Mach1design

[inaxeon]

I just managed to do the same thing to my SSA 3075X Plus, which err, costs quite a lot more.

Using an RF current transformer on a low powered DC setup. Literally the inrush current of charging a 470uF capacitor with the positive wire passing through the transformer was enough to blow the analyser input. I am absolutely astonished! I would not have expected it!

I will be buying that Tekbox transient supressor too. In the mean time I have reached out to Siglent. I hope they'll be as kind to me as they were to you.

[Jester]

What are the part numbers of the components that you replaced?

[inaxeon]

I meant that I've blown mine. Not fixed yet. Mach1 states that he replaced:

MASWSS0181TR-3000 (RF Switch)
BAR63-02V (Diode)
BZX84J-C30 (Diode)

MASWSS0181TR-3000 won't be what's in the SSA 3075X because that part is only 3GHz. Need at least 7.5GHz.

I don't know what's in mine. There doesn't seem to be any pictures or videos of the 3075X's RF deck yet either, and I'm not yet ready to break the warranty seal on mine until I hear form Siglent...

[oz2cpu]

this is the latest version SSA3021X see no diodes  !!
darn it my RF input is af deaf as it can be..

[TheDefpom]

is it just the lighting or is C7 chipped and cracked?