AnyFM tuner mechanics out there?


Perhaps  can shed some light on what's going on with my Mac MR 71?

Recently had the tuning dial cable restrung. Now I can't rotate the tuning dial to the right past 91.5! I can turn the dial all the way left. I popped the cover to inspect the cable, and don't see any obvious binding. For now I'm at least stuck with all the public stations I listen to.



Any idea what could cause the tuning mechanism to bind as described?
tablejockey
Dial strings are more likely to slip than bind. Inspect the string while turning the tuning knob and look for slip. If that’s what’s happening, applying a small amount of resin can remedy the problem.
Thanks for the responses.

cleeds-
The string is indeed slipping. Turning the dial to the right and helping the cable along, the dial is now moving freely. Couldn't determine where the slipping was occurring.

Moving the dial past 91 reminded me that there just isn't anything of substance left!

oldhvymec-thanks for the schematic. I have the tubed 71, but  likely there are  many similar things( like cable restringing)
I'm glad we have a few options for repair here in So Cal. Even though I repaired photocopiers in the 80's, I now wouldn't have the patience to even disassemble the Mac and attempt such a feat. I'd have left over screws and missing parts to account for!
tablejockey
cleeds-
The string is indeed slipping. Turning the dial to the right and helping the cable along, the dial is now moving freely. Couldn't determine where the slipping was occurring
Resin is your remedy. It's available in any good music store - the same stuff violinists use.
There is a spring located on the actual wheel that is on the tuning capacitor shaft. Is it loose or does it have tension on it? It should be stretched out to be about 3/4 of the distance between totally loose and the limits imposed by the wheel. Take a look. You may have to tighten it up slightly.

Sounds to me like whoever did the restringing didn't fully test it out. Restringing is a bit of an art.
For future work on your MR71, give Tom Carione at Brooks Berdan Ltd. in Monrovia (just East of Pasadena) a try. His fulltime job is as a maintenance technician at an L.A radio station (or is it a TV station?); he's in the shop on Saturdays.
There is a spring located on the actual wheel that is on the tuning capacitor shaft. Is it loose or does it have tension on it? It should be stretched out to be about 3/4 of the distance between totally loose and the limits imposed by the wheel. Take a look. You may have to tighten it up slightly.

atmashpere-
I took a look at the wheel, and there are 2 springs. 1 is extended and the 2nd, not so much. 
https://www.manualslib.com/manual/1001212/Mcintosh-Mr-71-Fm.html?page=10#manual
The movement is fine for now, but I will drop it off for adjustment soon.
Thanks!

bpd24- Berdan was my first call when I initially had the restring. They were minimum 1 month lead time, as Tom does his thing every other week right now. Ended up going to George Meyer in LA(closer)they are a authorized Mac repair facility. Had an amp repaired there before. They did 2 week turnaround. Good service, kinda pricey(it is LA) At least the adjustment should be no charge!


I took a look at the wheel, and there are 2 springs. 1 is extended and the 2nd, not so much.
@tablejockey  This is a pretty common setup. I suspect as you work it back and forth, the spring tension will equalize and it should be fine.
atmasphere-
Thanks for the insight! The tuning seems fine after giving the dial a few turns across the spectrum.

I wasn't looking forward to taking it back to the shop and being without the great sound the Mac delivers.