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Author Topic: Mamiya ZD back: what are the side contacts for?  (Read 3381 times)
ondebanks
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« on: June 21, 2012, 05:56:08 AM »
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I don't see this mentioned in previous ZD threads. The ZD back's user manual is silent on this also...

Does anyone know, what's the purpose of the recessed vertical strip of 12 electronic contacts on the ZD back?


There are no corresponding contacts on the 645AFD series bodies.
There are no corresponding contacts on the RZ67 ProIID ZD adapter (HX701).

There is a corresponding protrusion with 2 (not 12!) contacts on the RB67 ZD adapter (HX702), and on the 4x5 ZD adapter (HX401).

Hmm...this might be a wake-up thing, but since the 645AFD and ProIID/HX701 wake the back up through the usual horizontal contacts, and since the RB67 and 4x5 adapters also have these horizontal contacts and their own built-in power source, why are the 2 vertical contacts also needed?

Related question - has anyone managed to use any digital back other than the ZD on the RB67, using the HX702 adapter directly (no lens-to-back cables)? In particular, I'm thinking of the Phase One backs that need a wake-up signal?

Ray
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ondebanks
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« Reply #1 on: June 30, 2012, 05:23:09 AM »
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Anyone?

Surely a PhaseOne/Mamiya-Leaf dealer can answer this simple question? You guys still sell the HX701 and HX702 after all!

Ray
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yaya
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« Reply #2 on: July 03, 2012, 01:39:13 AM »
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Hi Ray,

I've asked my colleagues at Mamiya; The top 2 contacts are for Ground and for power supply to the adapters' CPUs (so the ZD back powers the adapters)

The other 10 do not have a function but they were placed there to allow for future expandability.

Hope this helps

Yair

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Yair Shahar | Product Manager | Mamiya Leaf |
e: ysh@leaf-photography.com | m: +44(0)77 8992 8199 | www.mamiyaleaf.com | yaya's blog
homeiss
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« Reply #3 on: July 03, 2012, 10:29:15 PM »
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I just received my HX702 adapter a couple of weeks ago. If you want to mount a Leaf or Phase One back you would have to remove the side contacts you're refering to. They are held on by two tiny screws. Once removed it reveals 12 contacts just like the ones on the ZD back. Then you should be able to mount a Leaf or Phase back to it. Since the adapter wouldn't receive any power at this point I'm guessing you could use it as a dumb adapter and use a sync cable straight from lens to digital back?

The HX702 seems to be the only adapter for the RB67 that actually maintains the ability to rotate, which is nice. Leaf has an adapter, but they are just two different plates, one for each orientation.
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ondebanks
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« Reply #4 on: July 04, 2012, 09:57:27 AM »
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Excellent - thanks for the replies, Yair and homeiss.

The HX702 was the one I was most interested in, as I can currently get it plus an RB67 ProSD body for around 650 combined. In contrast, it's hard to find an RZ ProIID and HX701 for under 2000. The lenses I am interested in are common to both.

Yair - could I trouble you further to find out the voltage and current specs drawn from the ZD, when it is powering the adapters? I don't have a ZD back, and like homeiss, I would intend to use this adapter with a different 645AFD-mount DB. After removing the 2 tiny screws, I could feasibly rig a connection straight from the HX702 adapter to a separate battery, if I knew what electrical spec the adapter requires.

Thanks again,
Ray
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homeiss
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« Reply #5 on: July 04, 2012, 04:22:46 PM »
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I know what you mean about prices for RB versus RZ... I had an RB67 Pro for 5 years, and just before I ordered the HX702 I picked up an RB67 Pro-S body for $53 on ebay!

I should have been more clear. I actually have a ZD back and use the HX702 with it. If I ever upgrade, I would definitely want use this adapter though.

Operation of the HX702 is a little bit weird. However, I have never had my ZD give me errors like it does when I use it on my AFD! If you push the shutter release halfway down the adapter lights up for 5 seconds. If the shutter is not fired within the 5 seconds the ZD just records a black frame. So for long exposures, you seem to be able to put it in Mirror Up mode then fire the body. The adapter will light up and as long as you fire the lens before the adapter light goes out in 5 seconds it will record the image for however long you want (I've only tried up to 8 seconds). The adapter "knows" when you push the shutter halfway because it uses the same mechanism that checks if a darkslide is present or not. So when the shutter is pressed, it pushes on the adapter and completes the circuit which then lights up the adapter, thus preparing it for capture.

I would be very interested to hear how it goes if you do try and mount a Phase back to it.

-Cory
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JonTScheuler
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« Reply #6 on: October 11, 2013, 09:38:24 AM »
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Hi Folks, I found this thread in a search, looking for info on the HX702 and a Phase One back. Pulling the "protrusion off the HX702 does allow my P25+ back to functions as a "Large format"-2-shot back. I've adapted a broken Kapture-group box to give me a "Wake-up" signal, by just removing the circuit board, and soldering the momentary switch across the sync cables lines (only 2 lines come from the flash sync on the lenses), I added another cable to allow the P25 sync cable to attach to(From a bad flash extension cable), as I also have a H-5 that I use too. I opened up the HX702 this am to look things over and verified the operation voltages for the microprocessor in the HX702. It appears to be a direct link to the Mamiya back for power, with the Plus going to the inside pin (pin towards the center of the adapter to wards the image sensor opening), and the ground (negative) connection going to the pin  nearer the outside edge of the HX702. I examined the circuit and found a capacitor marked with a plus (+) sign next to one side, and verified the other side as connecting directly to the chassis ground - hence the "negative" pin Mentioned above. The positive pins' circuit path goes through a couple of active components that would lead to the belief there is some "active" voltage regulation that occurs on the circuit board. It appears that a small 6 volt battery would fulfill the power requirements of the circuitry of the adapter, and not over-power the microprocessor. I haven't gone further yet, except to measure the physical clearance between the back and the HX702.(0.025 inch). Very small wires would be required for a carefully soldered connection to an external housing for a battery. Since the p25+ in a mamiya 645 mount is stated as communicating with the camera microprocessor through the horizontal pin group, the SHOULD BE no worries of power being in-approprietly applied to the back, but I don't know if I trust that "SHOULD BE" until I do a live voltage test on the adapter with-out the back attached. I have the lab equipment to regulate the voltage and current to determined levels, and will do that as time permits, but will continue to use the HX702 as a "Dumb" adapter (non-powered) that rotates on the rb67 for now. Does anyone else have any further info? Manufactuers don't want to talk to me at all, and it's nice to have a rotating back adapter even if I blow the circuitry in the adapter. Since the Digital backs pins are contacting the adapters' circuity wether the back is powered or not, and I'm getting good images with the unit as a "dumb" 2-shot adapter. I'll go that far. We'll se what I find out. (I've been "figuring things out" since the 60's) (and into photography since the late 70's)
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bill_c
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« Reply #7 on: October 17, 2013, 06:56:47 AM »
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Hi Jon, I've also been thinking about this for a while now, thanks a lot for the interesting post. A couple of thoughts on the matter:

It appears that a small 6 volt battery would fulfill the power requirements of the circuitry of the adapter, and not over-power the microprocessor.
I believe the ZD back has a 7.2 volt battery, I wonder if the external power connectors on the ZD back are directly connected to the battery, i.e. the correct voltage for the HX702 would also be 7.2 volts. Could someone with a ZD back please confirm the actual voltage on the external power pins (between the two topmost pins on the ZD's recessed vertical connector) using a multimeter?

I haven't gone further yet, except to measure the physical clearance between the back and the HX702.(0.025 inch). Very small wires would be required for a carefully soldered connection to an external housing for a battery.
Just a thought - wouldn't it be easier to just drill a small hole in the HX702 electronics housing and run a cable to an external battery through that hole?


Bill
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JonTScheuler
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« Reply #8 on: October 26, 2013, 05:00:26 AM »
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Hi Bill, Just now read your post. I believe it should be possible to drill a small hole for wires in the top housing, I hadn't considered that. I'll open up the adapter again in a day or 2 and verify that. I woke up this am early with this on my mind and decided to check my posts here, glad I did. (I've been working on other parts of the project, and an idea I had for another trigger to wake-up the backs. The prototype works - strictly mechanical switches, but mounted for easy access when using the Mamiya handle for "handholding the RB. I've done that in the past, but also have now modified the camera-mount screw in the handle to allow my monopod to mount up and help support the camera assembly. I was concerned this am by the combination of the microprocessor in the HX702 and the programing card that mounts in the ZD back in the front CF-memory card slot. If there are control signals that need to pass from this combination thru the adapter to the digital back, it might not matter what we do for a battery, since that program card won't exist with a different back. I'm going to also check to see if the switches in the HX702 that sense the 1/2 closed position of the RB trigger button are momentary or constant. This might explain why the back records a black frame if nothing triggers the main flash trigger sensing signal - meaning that if the 1/2 closed sensor switch is momentary, then there will be no power needed to the HX702 circuitry, and the trigger cable can be "hot-wired" to the flash connection jack in the HX702 - which the non-zd digital back's sync cable would then plug into - to be triggered by the flash sync in the lens. I'm planning on checking this out since I'm worried about frying the digital back with logical-high voltages from an "powered-up uncontrolled cpu" feeding the back with Logic-high signals. I've not been able to find out from Mamiya or Phase-One information on what the horizontal pins are for. Since I'm also going to be applying power to the HX702 (with out the back attached), but attached to a camera body/lens I'll be able to get more info then.  I haven't been able to do that yet, but this coming week should be able to do this. Jon
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JonTScheuler
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« Reply #9 on: October 26, 2013, 05:13:09 AM »
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Hi Bill, also to note - the ZD battery is rated at 7.4 volts, 1500mah. I did verify a couple of direct connections to the vertical power-strip/pins and the horizontal pins - this worries me as to putting my P25+ on a powered HX702, and not knowing what the horizontal pins are for. I can't afford to smoke the P25+. The micro-processor is nominally rated @ 5.5 volt.  Jon
« Last Edit: October 30, 2013, 04:55:47 PM by JonTScheuler » Logged
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