Advantest TR4131 Spectrum Analyser Problem (Pt 2)

[@comicaltester]

Most likely the first mixer has been damaged and you are seeing LO breakthrough. The CRT is fine, just repaired one which looks similar (not as bad) on screen. It had one diode in the single balanced mixer which was damaged...replaced both. A manual can be found here www.advantest.com/service-support/electronic-measuring-instruments/operating-manual-of-discontinued-products unfortunately not exactly the TR4131 but close enough to work out what is going on...good luck

[@lu1hko]

Hello Tony, I have a similar problem, could you fix it? Tnx .Fernando

[@T.o.n.y.T.]

Hello Fernando.. It's strange that I did reply here before to you but now I do not see my message.. I also did send you my email address but never heard back from you. You are welcome to still contact me if you wish.

[@lu1hko]

Hello. I have just received your reply!!. Not the previous one..... Sorry. I purchesed allí the smd att resistirse but i do not replece them. Todo mucho work here. I Will do asap and comment here. Tks for your interest. Fernando Costarelli

[@T.o.n.y.T.]

Good to hear back from you again Fernando. Yes let me know how you get on with your repair 👍@@lu1hko