Does anyone repair or rebuild the old Allen Bradley pneumatic timers or do you just upgrade to a newer part?

Trying to decide if it is worthwhile to get renewal parts for these vintage Allen Bradley timers or just move on at this point...

I see some of the parts are still listed as available, x-311256 bellows assy, x-221325 filter assy, and 40262-001-54 switch assy.

Looking for your thoughts on rebuild or update.

Thanks!
Ben

Gentleman,
How much difference is there between manufacturers of size 50 chain? We have ongoing issues with broken #50 drive chain on a conveyor system and I can't seem to determine a mechanical bind anywhere. So I would like to try a better brand of drive chain to rule out a cheap chain as the culprit.

Are there any recommendations of preferred chain manufacturers? How about brands I should avoid?

Thanks in advance...

It is  my understanding that a tach generator is nothing more than a mini generator. Is it possible to verify proper tach operation simply by spinning the tach and monitoring voltage? Is there anything else I should look for when troubleshooting a tach gen?

Thanks in advance for any help on this...

Hello,
During a normal workday we began experiencing a "feedback loss" alarm on a Reliance Flex-Pak drive. Can anyone point me in the right direction?

The DC motor is 50HP and we are using a tachometer for the feedback method. The tach was replaced in the last 6 months so I don't think it is the tach gen. 

Could there be a bad board in the drive?

Thanks in advance for any help.