Nikon DP-1 Big Repair Question

[henry_finley1]

<p>I have here n approx 1972 Nikon F2 with DP-1 finder that I'm working on. The meter was off by approx 1.5 stops in the direction of causing underexposure. I have re-calibrated it successfully for sunny f/16 at ASA 200 and it is correct there. However, when I carry the camera into increasingly darker areas to check linearity, I find it is still underexposing at the darker end of the scale. That is to say, and EV 3 is still underexposing by 1 stop. The point where accuracy starts turning sour is at an EV I can't recall, but let's say it's at a brightness where I can still go hand-held. Maybe 1/30 at the f/3.5 at ASA 200. The adjustment so far has required a turning a bit more of the potentiometer by close to 1/5 to 1/4 of a turn in the clockwise direction. If I go more to try to favor the dark end, I will be heading into territory where sunny f/16 will be overexposing.<br /> AHA!, I say to myself--meter cell or cells losing linearity (going bad). I've got a pretty fair bit of meter work under my belt, and this would be typical. But I have NOT disassembled the meter to clean and re-surface the carbon ring or clean the chrome-plated ring. The meter movement is not jumpy. It does have "Nikonitis" to a degree though. Where being off by a small amount from center deflects the meter more severely than the equal amount the opposite way from dead center. Nikon and Nikkormats have this peculiarity more than other makes I've dealt with.<br /> So my question: If I proceed to do the standard brush-and-ring cleanup, can I hope to clear this problem up some, or will this require a stripdown to go after the high and low pots? Thank you</p>

[robert_bouknight1]

<p>I would check the battery box connections. Seems like the connections were problematic on some of the older cameras.</p>

<p>My F2 and even older F meters all seem to be in the ball park without routine calibration.</p>

[henry_finley1]

<p>Well let's approach this from another angle since initial response is low at this time. I've had the underside of a DP-1 apart, but not the top side. I have the assembly manual diagram here. But I'm fuzzy on the top cover procedure. It looks like I might gain access to the high and low trim pots just by taking off the top sheet metal cover. But that little contact tip on the rear left side bothers me. Is that contact tip soldered to something--a wire or such, whereas I risk messing up something in relation to that contact tip?</p>

[henry_finley1]

<p>Additionally. I wonder where Sover Wong gets his new CdS cells.<br>

http://soverf2repair.webs.com/Cds.htm</p>

 

[jim_momary]

<p>Not that it helps, but perhaps the most common/available source of ots CdS cells is via Digi-key.</p>

<p>For example, </p>

<p>http://www.digikey.com/product-search/en/sensors-transducers/photo-detectors-cds-photoconductive-cells-ambient-light/1967023</p>

<p>One needs to know physical size and light & dark resistances in order to find the appropriate sub (if it is not a custom one).</p>

<p>I mainly use Digi-key, Newark and Allied for all my electronic projects at work ... they seem to stock just about anything imaginable.</p>

<p>Jim M.</p>

 

[henry_finley1]

<p>Thank you Jim. I still hope somebody addresses my earlier question, but with regard to the secondary question on buying new cells, I'm not yet comfortable with just the electrical and physical characteristics. Those alone might not be an adequate replacement. I happen to know some cells in these cameras had their own built in lenses which gave the meters their center/spot, or weighted readings. Put just any cell in that fits the specs could well be worthless if the metering pattern is not in keeping with the original.</p>

[sergio_sousa]

Hi there!

 

I know this is an old thread, but I am in the process of trying to repair a DP-11, very similar to the DP-1, light meter.

With the light meter assembled, testing the batt contacts for resistance, I get more ohm or less If I aproach my hand from the glass or let mor light in. It also varies if I rotate the speed selector and/or the apperture ring conection.

I would say all the circuit is in good order, except the needle driver (do not know the name of the part), can this happen?

Battery test is also dead, I get no readings never.

I opened the meter on its two halves, did a good job cleaning everything, but no changes...

 

Any hint on how to test the needle driver to see if this is the culprit? If it is, can I buy one somewhere?

 

Thanks in advance for all the possible help!

 

Sergio

[rodeo_joe1]

Do you get any deflection with the test button?

And you do realise you have to turn the meter on by pulling the lever-wind to its standoff position?

[johnsabella]

Another option is to buy a DP-3 (which came on the F2SB model). The DP-2 (which came on the F2S model)was a step up but still used Cds cells. It had a better range than the DP-1 and added + and - LED's instead of a needle. I bought a F2S that Nikon USA did repair for me in the mid 1980's. They told me ordinarily they stopped

repairing years ago. They even relined the entire Mirror box too.

I own a F2SB and the DP-3 uses Silicone Blue Cells. Much more wider EV range and instantaneous sensitivity. If you target on a bright image with a DP-1 the sweep over to a Dark scene, there is a momentary hesitation to register. With the DP-3 it adjusts immediately. If you want to upgrade to Ai, then find a DP-12 meter( it came on F2AS models. It also has the Silicone able Cells too. So far my F2SB has no repair issues.

Quite a few show up on eBay. Good luck with what ever you choose!

[ben_hutcherson]

The DP-3 remains my favorite way to shoot non-AI lenses.

 

The EL does give you AE, but I've always found mounting lenses on Nikkormats to be a pain. I guess if they're all you use and you never mess with lenses off the camera they're going to be f/5.6 when you pull them off, but otherwise I find it a pain to make sure they're set there. Otherwise, the DP-1/DP-3/DP-3(and all the F meters) are fine with mounting the lens with the aperture ring set to whatever-of course I usually go to minimum to "pick up" the pin, and then maximum of course to set it.

 

The only potential weakness of the DP-3 and DP-12 is that the contact fingers can wear and cause issues. Sover Wong has a replacement that should last longer than any of us will be alive, but it's also expensive.

[BeBu Lamar]

<p>I would check the battery box connections. Seems like the connections were problematic on some of the older cameras.</p>

<p>My F2 and even older F meters all seem to be in the ball park without routine calibration.</p>

Reading Henry post he seemed to know what he is doing and I don't think battery is the problem (or connection is the problem).

[rodeo_joe1]

sergio_sousa was last seen: Jan 27, 2019