Seller responded quite quickly, and asked for video of the problem sent to an external (from ebay) email, along with a repeat of the description of the problem and the order number.
...the usual tactics of letting people jump through a succession of hoops in the hope that they'll eventually give up. Have they already offered you a refund of something like 1 percent of the auction price?
They haven't offered anything as yet. I'm certainly not paying anything for this one, they can send me a return label. It may or may not be fixable, in point of fact the PLL lock LED actually comes on properly now, but the performance otherwise is unchanged.
The fact they asked me to communicate outside ebay undermines their case massively; ebay will frown deeply when they see that and likely come down 100% on my side regardless of anything else.
Oh, here are the pics I sent. You can see the frequency is miles off, and the waveform at the lower frequency is horrible.
I agree on the assesment that the seller would like to dodge responsibility, but also I can see that they want "good proof" the unit is actually faulty (they also have likely been scammed by dishonest buyers). One might argue they want video because "flickering lock-LED & jumping frequency" is
really hard to convey in a picture - email is most likely the "most easy" way for both partys to get the video from one to the other. Also, I might add, your pictures of it working on some specific frequencies might be interpreted by a suspicious seller as "unit is working, buyer is trying to get it for free".
Also, the non-sinusoidal waveforms are expected! I think the PLL IC operates in "frequency divider mode" up to 2.2GHz, and that divider output is more or less a square wave. I think I mentioned that but worded it less directly before. Also also I might add that with such high harmonic content (as in a square-ish wave) even at "low" frequencies (say 50MHz) there might be a lot of energy up to 500MHz in those fast edges - which means you want to pay close attention to terminate your transmission lines, before trusting / judging what you see on the scope. That cable might be "too short for funny effects" at 50MHz but surely not at 500... As in have a scope with 50
![Ohms \$\Omega\$](https://www.eevblog.com/forum/Smileys/default/omega.gif.pagespeed.ce.G89vbH4KGC.gif)
input mode (best case) or use a BNC through-termination or at least a BNC-tee with a terminator. You can easily see the effect (IF there is one
![Wink ;)](https://www.eevblog.com/forum/Smileys/default/xwink.gif.pagespeed.ic.cldandycH0.png)
) in the latter case when plugging / unplugging the terminator
![DMM :-DMM](https://www.eevblog.com/forum/Smileys/default/smiliey_dmm.gif.pagespeed.ce.CvRqtDiING.gif)
Good luck!
![ThumbsUp :-+](https://www.eevblog.com/forum/Smileys/default/icon_smile_thumbsup.gif.pagespeed.ce._JElyJQqdB.gif)