A very interesting Hasselblad 203FE signal tapping

Recently have encountered a very interesting 203FE camera with a strange wire soldered to its motherboard. I have no idea of its purpose. I would like to see if I can get any luck here.
It looks to me like some signal taping or external trigger connection. It is soldered to a transistor-like SMT element on its motherboard. This wire is actually very well made, it seems like some third-party professional work. There is actually one inline resistor encapsulated in the heat shrink tube. The motherboard's function is not affected by this wire.
My guess is if this signal tapping is for use with a digital back to send trigger signals or to do some remote-controlled triggering.
Here goes some photos.

But why is that connector a "flying wire" and no mounted connector? And how does one reach this connector?

To me it rather looks like a custom tap for some regular testing. But then, could its blank metal rim (or socket) not produce a shortcircuit when just pushed into the casing for storage?

AgX said:

But why is that connector a "flying wire" and no mounted connector? And how does one reach this connector?

To me it rather looks like a custom tap for some regular testing. But then, could its blank metal rim (or socket) not produce a shortcircuit when just pushed into the casing for storage?

Click to expand...

I honestly have no idea, it is literally just a flying wire. One end is some kind of pin socket. A short circuit is exactly something I am worried about, and that may be the reason they put an in-line resistor there just to prevent such things from happening. The previous user seems cut a notch in the plastic casing, so the connector can stick out from there. Here are some additional photos. (I have temporarily removed the wire)

Thank you for presenting this case. And be it just for our daily dose of weirdness.


I assume as long noone identifies that transistor(?) pin, we will remain clueless, likely even then...

This is a guess.
A trigger for an early digital back?

MattKing said:

This is a guess.
A trigger for an early digital back?

Click to expand...

That's one of my guesses, and I am actually hoping that way. I want to find a reliable way to attach digital backs to Hassel 200 series cameras.

MattKing said:

This is a guess.
A trigger for an early digital back?

Click to expand...

In case this trigger idea would make sense tapping-wise, would one then not use a 2-pole connector?
And mount that connector in the casing? If one would like to be able to redo this to the original version, would one not, for anything beyond testing, mount the respective connector at least by adhesive tape to the casing?

AgX said:

In case this trigger idea would make sense tapping-wise, would one then not use a 2-pole connector?

Click to expand...

Instead, could this tapping be intended as capacitative one?

Or maybe the other pole, the ground, is just achieved via the mechanical back-to-body contact.

I looked at a 203FE service manual that is at galerie-photo and it has a picture of the circuit board but no actual information on the electronics. Also google searching (I don't know much about 200-series Hasselblads) revealed that Hasselblad used to do a modification to this camera to allow triggering a digital back.

If it were me, I would use an oscilloscope to measure the voltage on this wire (using the chassis as ground) when the camera is fired, and ideally the time offset of any signal versus the PC sync signal (need a 2-channel oscilloscope to measure both signals). I do not know whether the trigger would operate just by closing a contact, like a PC sync, or whether it pulls up a voltage on the pin. If it just closes a contact, then you'd want to have some way of sensing that by putting a small voltage on the test pin. Obviously that would require some care.

My guess is that you are correct that the inline resistor is a current limiting resistor to protect the mainboard and the external apparatus from one or the other's applied voltage, also possibly from static discharges or momentary shorts while connecting the two.

As I understand it, they modified the trigger pin at the back of the camera to trigger the older CFV back, and does not sound like they do anything like this. With the CFV II 50C back, I think they did some magic with the ISO pins, but not sure.

Anyway, I do suspect it's some kind of DIY solution to trigger a digital back. The only thing that might make sense?


p.s. I can't say enough how well the 203FE works with the CFV II 50C. It really is amazing. I get a blank frame maybe 10% of the time, so you do have to be careful and you have to set the camera ISO manually, but otherwise, shooting digital with a large ground glass on the 203FE is a sublime experience