Pentax KX by-pass surgery

stevebrot · 07-01-2012, 11:03 AM

For the OP...things could be worse! You could be shooting with my Ricoh XR-2s where the shutter will not fire if the advance lever is not in the "ready" position. That is, of course, unless you are using the autowinder, in which case both meter and shutter are enabled when the winder is turned on. For what its worth, the wind lever as meter switch functionality was very common back-in-the day for both pro and consumer models.

Steve

Last edited by stevebrot; 07-01-2012 at 11:11 AM.

Ratmagiclady · 07-03-2012, 09:20 AM

Originally posted by Moe49

(refer to post #1 & #4)

My KX is currently at Eric's getting a new top cover, new bottom plate, and new film door installed (new parts sourced from nice fellow in Canada).
I have asked Eric to perform the 'KX by-pass' surgery I had heard about here at PF, while he has the top of the camera removed.
It is Eric who is asking how this is done. Apparently, I am the first to ask this of Eric (?)

Well, there must be some wiring or other connection in there which requires the lever to be in the open position to complete the circuit: in some order, it should go battery-meter-lever-shutter release-battery. So all that ought to need to happen is to cut the advance lever switch out of that 'loop,' either by clipping the wires that go to that and connecting them to each other, or just splicing in a wire that goes around that advance lever switch.

(I don't know if there's some complication in there that Eric knows about that I don't. Does anyone have images of what it looks like under there?

)

**TomB_tx** · 07-03-2012, 10:40 AM

I'm quite sure there is only one switch in the KX. As the shutter button is depressed half-way, and the wind-lever is out, a latch mechanism moves against the button shaft to keep it from going back up, locking the meter on. In the KX I believe the switch is activated by the movement of that latch mechanism, not the shutter button. (The movement of the button only allows the latch to engage.)
On the MX and LX the switch is activated by the shutter button itself, not the latch, so the meter activates whether the latch is freed by the wind lever or not.
I think that's why Eric is confused about doing this modification, as the switch would be activated by a different part of the mechanism.

Ratmagiclady · 07-03-2012, 05:33 PM

Originally posted by TomB_tx

I'm quite sure there is only one switch in the KX. As the shutter button is depressed half-way, and the wind-lever is out, a latch mechanism moves against the button shaft to keep it from going back up, locking the meter on. In the KX I believe the switch is activated by the movement of that latch mechanism, not the shutter button. (The movement of the button only allows the latch to engage.)
On the MX and LX the switch is activated by the shutter button itself, not the latch, so the meter activates whether the latch is freed by the wind lever or not.
I think that's why Eric is confused about doing this modification, as the switch would be activated by a different part of the mechanism.

Hrm, That elucidates the confusion. (I'm not sure why they would design it that way, though, but they obviously did.) Not knowing details, I suppose that means you could bypass the lot of it to be 'always on?' *thinking.* So, this means that in order to activate the meter, you must both have lever out and half-press-the shutter, and once both are done, you must fold wind lever in to turn it *off?* Hrm. I think what I'd do there would be to just bypass the whole electrical bit of that wind lever, and just make a nip in the top cover to let some wires out, and stick a little pressure switch like for a tactical light to the front of the camera.

(I'm pretty sure there's a cheapie Radio Shack version of this kind of thing, but I don't know how long they'd last) But, you know, make it purely electrical. Just take the wires, extend em outside the case, and hook em to a switch, of any kind, really.
Metering on demand.

Last edited by Ratmagiclady; 07-03-2012 at 05:38 PM.

Hilo · 07-04-2012, 10:56 AM

Originally posted by Ratmagiclady

Hrm, That elucidates the confusion. (I'm not sure why they would design it that way, though, but they obviously did.) Not knowing details, I suppose that means you could bypass the lot of it to be 'always on?' *thinking.* So, this means that in order to activate the meter, you must both have lever out and half-press-the shutter, and once both are done, you must fold wind lever in to turn it *off?* Hrm. I think what I'd do there would be to just bypass the whole electrical bit of that wind lever, and just make a nip in the top cover to let some wires out, and stick a little pressure switch like for a tactical light to the front of the camera.

(I'm pretty sure there's a cheapie Radio Shack version of this kind of thing, but I don't know how long they'd last) But, you know, make it purely electrical. Just take the wires, extend em outside the case, and hook em to a switch, of any kind, really.
Metering on demand.

I'm the happy owner of the modified KX this thread started out with: no external switch was used. As I wrote before, all I know is that an original K2 part was used. This modification was done by a repairman in Prague, who was the chief repairer with Pentax for a long time. I don't live there, nor do I speak the language and have asked a friend to ask the details on this modification. It is holiday time and will take a while . . .

Obviously I had no problem giving instructions for this modification, and before my KX was sent to this repairman, I was even open to an external switch. But, after getting the KX back just as it looked before, I am glad that wasn't done. So, I would walk around Radio Shack's cheapies and have a little patience . . .

07-03-2012, 09:20 AM	#32
Ratmagiclady Veteran Member Join Date: Nov 2008 Location: GA Photos: Gallery \| Albums Posts: 13,563	Originally posted by Moe49 (refer to post #1 & #4) My KX is currently at Eric's getting a new top cover, new bottom plate, and new film door installed (new parts sourced from nice fellow in Canada). I have asked Eric to perform the 'KX by-pass' surgery I had heard about here at PF, while he has the top of the camera removed. It is Eric who is asking how this is done. Apparently, I am the first to ask this of Eric (?) Well, there must be some wiring or other connection in there which requires the lever to be in the open position to complete the circuit: in some order, it should go battery-meter-lever-shutter release-battery. So all that ought to need to happen is to cut the advance lever switch out of that 'loop,' either by clipping the wires that go to that and connecting them to each other, or just splicing in a wire that goes around that advance lever switch. (I don't know if there's some complication in there that Eric knows about that I don't. Does anyone have images of what it looks like under there? ) Last edited by Ratmagiclady; 07-03-2012 at 09:29 AM.

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07-01-2012, 11:03 AM	#31
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	For the OP...things could be worse! You could be shooting with my Ricoh XR-2s where the shutter will not fire if the advance lever is not in the "ready" position. That is, of course, unless you are using the autowinder, in which case both meter and shutter are enabled when the winder is turned on. For what its worth, the wind lever as meter switch functionality was very common back-in-the day for both pro and consumer models. Steve Last edited by stevebrot; 07-01-2012 at 11:11 AM.

07-03-2012, 10:40 AM	#33
TomB_tx Loyal Site Supporter Join Date: Jun 2011 Location: Texas Photos: Gallery Posts: 1,446	I'm quite sure there is only one switch in the KX. As the shutter button is depressed half-way, and the wind-lever is out, a latch mechanism moves against the button shaft to keep it from going back up, locking the meter on. In the KX I believe the switch is activated by the movement of that latch mechanism, not the shutter button. (The movement of the button only allows the latch to engage.) On the MX and LX the switch is activated by the shutter button itself, not the latch, so the meter activates whether the latch is freed by the wind lever or not. I think that's why Eric is confused about doing this modification, as the switch would be activated by a different part of the mechanism.

07-03-2012, 05:33 PM	#34
Ratmagiclady Veteran Member Join Date: Nov 2008 Location: GA Photos: Gallery \| Albums Posts: 13,563	Originally posted by TomB_tx I'm quite sure there is only one switch in the KX. As the shutter button is depressed half-way, and the wind-lever is out, a latch mechanism moves against the button shaft to keep it from going back up, locking the meter on. In the KX I believe the switch is activated by the movement of that latch mechanism, not the shutter button. (The movement of the button only allows the latch to engage.) On the MX and LX the switch is activated by the shutter button itself, not the latch, so the meter activates whether the latch is freed by the wind lever or not. I think that's why Eric is confused about doing this modification, as the switch would be activated by a different part of the mechanism. Hrm, That elucidates the confusion. (I'm not sure why they would design it that way, though, but they obviously did.) Not knowing details, I suppose that means you could bypass the lot of it to be 'always on?' thinking. So, this means that in order to activate the meter, you must both have lever out and half-press-the shutter, and once both are done, you must fold wind lever in to turn it off? Hrm. I think what I'd do there would be to just bypass the whole electrical bit of that wind lever, and just make a nip in the top cover to let some wires out, and stick a little pressure switch like for a tactical light to the front of the camera. (I'm pretty sure there's a cheapie Radio Shack version of this kind of thing, but I don't know how long they'd last) But, you know, make it purely electrical. Just take the wires, extend em outside the case, and hook em to a switch, of any kind, really. Metering on demand. Last edited by Ratmagiclady; 07-03-2012 at 05:38 PM.

07-04-2012, 10:56 AM	#35
Hilo Closed Account Join Date: Oct 2009 Posts: 161	Originally posted by Ratmagiclady Hrm, That elucidates the confusion. (I'm not sure why they would design it that way, though, but they obviously did.) Not knowing details, I suppose that means you could bypass the lot of it to be 'always on?' thinking. So, this means that in order to activate the meter, you must both have lever out and half-press-the shutter, and once both are done, you must fold wind lever in to turn it off? Hrm. I think what I'd do there would be to just bypass the whole electrical bit of that wind lever, and just make a nip in the top cover to let some wires out, and stick a little pressure switch like for a tactical light to the front of the camera. (I'm pretty sure there's a cheapie Radio Shack version of this kind of thing, but I don't know how long they'd last) But, you know, make it purely electrical. Just take the wires, extend em outside the case, and hook em to a switch, of any kind, really. Metering on demand. I'm the happy owner of the modified KX this thread started out with: no external switch was used. As I wrote before, all I know is that an original K2 part was used. This modification was done by a repairman in Prague, who was the chief repairer with Pentax for a long time. I don't live there, nor do I speak the language and have asked a friend to ask the details on this modification. It is holiday time and will take a while . . . Obviously I had no problem giving instructions for this modification, and before my KX was sent to this repairman, I was even open to an external switch. But, after getting the KX back just as it looked before, I am glad that wasn't done. So, I would walk around Radio Shack's cheapies and have a little patience . . .