Should repaired equipment be stated in the ad??

It can be a plus but it depends on who does the work. ARC still services everything they have ever made and any piece of their used gear you send to them will come back sounding as good as it ever did unless they tell you ahead of time that it can't. VPI, Well Tempered and MIT pretty much the same in my experience. Likewise Vandersteen and Thiel, although it's not always worth repairing speakers.

For an aftermarket repair shop, by far the best I've encountered for electronics is Stereo Surgeons in Hartford, CT.

Then there are vintage electronics: I happen to have a Hickock 539C Tube Tester that was repaired and calibrated by Chris Haedt. Documenting his having worked on it would greatly increase its sale value today.

hi Kijanki, that's not what I said. If you read statement once more - I said

if a component was recently serviced by the manufacturer or reputable tech, it may indeed have higher value (eg, an older amplifier newly recap'd) than one that is original/never serviced.

read that it MAY have, not DOES have

So to answer your question, I would pay more for a unit that has been repaired, than for one that is broken. And, I *may* pay more for one that has been recently serviced (ie checked out, biased, etc) by the manufacturer than for one that has not been checked out in years by a qualified tech, especially if the alternative units available are in unknown, unverified condition. Example: a few years ago I did indeed pay slightly better than market price for a Bedini 100.100 power amp that had been serviced and recapped by Bedini 2 years previous. This is a 1987 vintage amp. In this case the seller did advertise the service. Likewise I paid more for my Electron Kinetics Eagle 2C amp than I did for my Eagle 2A - the difference between them being that the 2C had undergone a refurbish/upgrade. I paid more than 2 times as much for it, and would do it again.

So, as I said, I think it depends on the equipment.

I believe that is not so important what I think but rather what possible buyer might think. I don't want anybody to feel bad after purchasing things from me, so I would reveal what I know.

If I go by what I think then we enter dangerous territory - one might sell house that was rebuilt after big fire without disclosing it because it has, in his opinion, even greater value.

It's always best to be honest about repairs.