Originally posted by normhead So essentially you were hoping they'd use a repair procedure that went against their repair protocols. This is always a problem for repair technicians. They know if they do this one thing it will work, the customer wants them to spend time investigating something else they don't know will work. But they have to warranty the repair, not the customer. You can't expect an official repair depot to encourage or support non-authorized modifications.
It seems to me, you were simply unwilling to accept that their solution was the best one. They said they would solve the problem, you didn't believe them. All they want to do is return you a working lens at a reasonable price in a reasonable time frame. For me that's enough.
There is always the possibility that if your understanding of how the lens works is not the same as their's, they have no idea of what you're talking about. In this case it's quite possible that some part of the SDM assembly is necessary for the screw drive to function. Especially likely since the lens didn't function in either screw drive or SDM, and that fixing the SDM would also fix the screw drive, and was the only way to fix the screw drive. But I'm just speculating. My point is, sometimes you just have to let the technicians do their job and not burden them with possibly extraneous information.
It's just not reasonable to expect an authorized repair facility to explain exactly how the lens works, to justify their repair procedure, or to repair a lens not consistent with factory spec. But if you want to pay an independent repair technician to do that, that's your choice.
Well, you really misunderstood what I was trying to say, which might be because I can't express myself, I concur! I also left a lot of the details out because I didn't think they were important as I felt confident my concern about communication was justified.
For specialty repair and long diagnosis, I have a camera repair guy I go to. He was actually the guy to tell me he thought it could be a problem with a "spring" (I can't remember what he said exactly...) pushing the glass elements around while zooming (he looked through the lens with a magnifying glass). He said a particular Canon lens was built rather similarly. To demonstrate the alignment problem, he tried to focus at 90mm or so, and when the camera couldn't quite get the focus confirmation, he gently tap the side of the lens, near the front element, and sure enough, it acquired focus. He repeated a few times with the same result each time. I wanted him to attempt a repair, but he wasn't keen on the idea of opening a lens he knew not much about, being mostly a Canon, Nikon repair guy, as well as an film era camera expert.
Anyhow, I actually agree with everything you say. I certainly didn't ask for them to try to convert the lens and I wasn't expecting them to spend hours diagnosing a problem that I might have invented. I did ask if they had an older Pentax body to test the lens on because when he got the lens, he said the SDM motor wasn't working anymore, so he couldn't experience the focussing problem for himself (which did piss me off a little bit, because the SDM was working when I sent in the lens). Most of my concerns started there, because he couldn't experience the problem himself. It left me with the fear that I'd have to pay for a SDM motor while the problem might be something else entirely, and they'd find out only after, so I'd probably have to pay for a motor.
When communicating with them, I wasn't trying to outsmart Sun's technician, rather, I was hoping to get information about the possible problem. When they sent their diagnosis, they said the SDM motor needed replacement, which it probably needed, because it was rather slow when I sent the lens. However, when I voiced my concerns about the possibility that there was something else going on, the technician never tried to acknowledge the possibility nor did he explain that the SDM motor was likely responsible for everything. In the end, he said "we'll change the SDM motor and test it. If it doesn't work, we'll let you know". That's perfectly fine, of course, but considering the SDM motor was still working when I sent the lens and that I had converted it to screwdrive focus to test it beforehand, I was mostly trying to avoid changing the SDM - but not if it was indeed the problem. In the end, there was two operations performed on my lens as per the repair sheet I got back with the lens. The SDM motor and something about - cleaning and adjustment - I can't remember exactly what it was, but it wasn't clear. Maybe it was standard procedures that follows a SDM replacement, maybe something else. So, was the SDM motor truly the problem? Maybe, maybe not, and I believe good communication could have clarified that.
Thus, my opinion remains the same. Sun Camera seems like a competent repair facility, but they don't include a lot of details of what is performed on the lens. Of course, they will try to change the big and expansive parts first, which I believe is the more efficient way to do repairs for them, but not necessarily for the consumer. In my experience, which was rather limited and in a "strange" situation, Sun Camera wasn't great on communication, but they delivered a perfectly working lens in a timely fashion.
I hope my experience can be of use for some of you.