problem RB67 lens

David T T · Mar 11, 2018

Hey everyone. I have an RB67 with the Sekor C versions of the 50/65/90/127 and 180mm lenses. Of these, I use the 65mm the most by a wide margin.
This lens, though optically wonderful, has been problematic. When I first bought I got blank frames. No problem, it looked like it had been unused all of its life, had it CLA'd, worked fine. Until I started using it with speedlights, and it stopped firing the flashes. I guess the tech didn't clean the PC ports. Sent it out again, and it came back firing the flashes. Awesome. But last week at an indoor fashion shoot, I was shooting some instant film with my RB, testing the space, and I started getting blank frames. I ended wasting a full pack of fp-100c until I could finally believe this lens, which has been to the tech TWICE, was f*#$@&g up again.
So here's my query. My tech never indicated any parts of the lens were getting worn or weak, so can I assume the lens is repairable? I have in retrospect not been thrilled with that tech, so if I send it out, it will probably be to Zack's or someplace like that. I really don't want to buy another, which will then need a CLA as I depend on this focal length. Buuut I will if I have to.

Any thoughts?

shutterfinger · Mar 11, 2018

Its been years since I had a Seiko shutter open. Mamiya uses Seiko shutters. If memory serves its a straight forward mechanical contact that makes when the shutter blades reach 95% to 100% full open. The contact is not extremely robust or fragile which leads to the strobes in use. What is the trigger voltage of the strobe(s)? Is one strobe set as master and others as slaves? A high sync voltage may be arcing and burning the contacts. A PC terminal has the outer sleeve connected to the shutter case and the triggering mechanism connects the center contact to the shutter case to fire the flash.
Paramount Cords http://www.paramountcords.com/product-category/accessories/ has two PC tip conditioning tools in its Accessories section. A loose fitting PC cord will not trigger a flash. The outer sleeve of the cord or the center contact may not be making or the PC socket on the shutter may be worn so that a cord cannot make good contact. I've had cords that would work with the cord in one position only even though it could swivel a full 360°.

David T T · Mar 11, 2018

The PC port isn't the problem, that was resolved, as I stated.

The problem is the shutter isn't working. And it has been CLA'D, as mentioned previously. So, to reiterate, I need to figure out whether I have a bad tech or a irretrievably bad shutter.

WilmarcoImaging · Mar 11, 2018

One more question on the strobe - are you using a radio trigger or PC cord connected directly to the strobe?

I would buy another lens.

Trail Images · Mar 11, 2018

OP.....I have the same collection of lenses and a couple others too. I find them all wonderful and have found the 65 my go to for most standard takes. I've had various lens failures over time and only had one non fixable. It had fungus attacking it. I always sent my lenses to KEH and paid the price there. But I never had to return a lens once fixed either.
Good luck with your next decision.

E. von Hoegh · Mar 11, 2018

David T T said:
The PC port isn't the problem, that was resolved, as I stated.

The problem is the shutter isn't working. And it has been CLA'D, as mentioned previously. So, to reiterate, I need to figure out whether I have a bad tech or a irretrievably bad shutter.

The shutter has been "serviced" twice by the same tech., with leftover issues each time. If it was unrepairable, you should have been told.

David T T · Mar 11, 2018

WilmarcoImaging said:
One more question on the strobe - are you using a radio trigger or PC cord connected directly to the strobe?

I would buy another lens.

It fires both a strobe directly, and via a radio trigger. No issues.

David T T · Mar 11, 2018

E. von Hoegh said:
The shutter has been "serviced" twice by the same tech., with leftover issues each time. If it was unrepairable, you should have been told.

My thoughts exactly. I'm inclined to send it to a new tech like Zack's to see what's up.

David T T · Mar 11, 2018

Trail Images said:
OP.....I have the same collection of lenses and a couple others too. I find them all wonderful and have found the 65 my go to for most standard takes. I've had various lens failures over time and only had one non fixable. It had fungus attacking it. I always sent my lenses to KEH and paid the price there. But I never had to return a lens once fixed either.
Good luck with your next decision.

Cheers.

shutterfinger · Mar 11, 2018

If your go to tech isn't a Mamiya authorized repair person/shop sent it to one. Its rare for the mechanics of closing the contacts to operate intermittently, something is badly worn or misadjusted if its internal of the shutter.

David T T · Mar 11, 2018

shutterfinger said:
If your go to tech isn't a Mamiya authorized repair person/shop sent it to one. Its rare for the mechanics of closing the contacts to operate intermittently, something is badly worn or misadjusted if its internal of the shutter.

Ok, I'll make that part of my criteria ty.

MattKing · Mar 12, 2018

Are there any Mamiya Authorized techs left that are "authorized" with respect to film equipment?

David T T · Mar 12, 2018

Not sure MattKing, but I'm going to look. I need this lens back in fighting condition.

tedr1 · Mar 12, 2018

This is what is located behind the lens body flash-PC terminal, this is the shutter from an RB67 150mm lens, I believe the same shutter is found in the 65.

The small round stubby terminal about 3/4 the way between the center and the right hand edge is the connection between the internal shutter flash actuator and the external terminal. The design is a sliding contact that is necessary to permit dismantling of the shutter.

Slightly to the left and lower down can be seen the tip of the yellow brass lever that operates the selection between M and X sync.

For those curious here is the face-on view

The brass face rotates for shutter speed selection, around the rim the V notches between 11 o'clock and 2 o'clock are the detents for the speed settings. (this shutter died from failure of the three slow speeds).

The lever referred to above for MX flash selection is at 8 o'clock.

problem RB67 lens

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