ZoneMaster II Button Replacement

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           RH Designs ZoneMaster II

I have had an RH Designs ZoneMaster II enlarging meter for years that I use regularly.  A few weeks ago I noticed that one of the buttons had become unreliable.  I had to press it hard several times to get it to work.  Since I am in the US and RH Designs is in the UK, I decided to try and fix it myself.  As it turned out, that was not terribly difficult.

I should note that electronics has been both a hobby and career for me, so I am used to working on electronics circuits.  If you are not comfortable doing simple electronics repair work, you might not want to attempt this.  If you decide to go for it, you can reduce the risk of damage by using an anti-static wrist strap.

SKHHBWA010

             ALPS SKHHBWA010

I can’t say precisely what button was used in the manufacture of the ZoneMaster II, but  ALPS makes a close match.  The ALPS part number is SKHHBWA010.  I ordered  from Mouser at $0.15 each plus a small shipping fee. To see an accurate picture of the switch you may have to click on the data sheet rather than relying on the representative illustration shown on the website.

The ZoneMaster can be disassembled by removing the four black Phillips head screws on the bottom and carefully separating the top and bottom of the clam shell box..  I recommend checking to make sure the power switch is turned off and then removing the battery.

Open Clam Shell Box

                                                  Open Clam Shell Box

The circuit board is held in place by three short Phillips Head screws, one in each corner.  Be careful not to accidentally damage the push-button power switch.  Jewelers screwdrivers come in handy at this point.

Circuit board removed from box

                                Circuit board removed from box

Carefully work the circuit board out of the plastic box and turn it over to see the buttons.  To remove the buttons you will need a small soldering iron (25-50W or so) and either a “solder sucker” or some solder wick.  Flip the circuit board back over and desolder the faulty button.  The molten solder can be sucked off with the solder sucker or soaked up with the solder wick.  Being too rough or using too much heat for too long can damage the fragile copper traces on the printed circuit.  After removing the solder, use small needle nose pliers or tweezers to work the pins loose so the button can be removed.

Faulty button removed

                                           Faulty button removed (yellow circle)

The new button is a match for the old faulty one and seems to require very similar operating force.  The “click” sound made by the new button is a little different, although certainly not enough to matter to me.

New button is on left, old on right

                                New button is on left, old on right

The hole pattern for the switch is rectangular, so it can be installed in two ways.  Since the pins are symmetrical, it doesn’t matter which way you install it.  Be sure to press it all the way into the holes on the circuit board and solder all four pins.

Reassembly is the reverse of disassembly.  Be careful not to strip out the holes in the plastic box when reinstalling the screws and remember to reinstall the battery before buttoning everything up.  It might not be a bad time to replace the battery while you have everything apart.

If everything went well, you didn’t ruin your very expensive enlarging meter.

Nothing is Ever Simple

In the process of adding older pictures to my website galleries, there was one I wanted to add but apparently lost the print.  So, today, I reprinted it.  The first print I made was of the wrong negative.  Duh.

The second print I made was great except for one tiny dust speck.  Rather than spot it, I decided to hunt down and destroy the dust particle.  It turned out to be stuck on the negative and would only come off after I used a moist Q-Tip on it.  I made another print and the speck was gone.  Success!  But, wait.  It didn’t look right.  Slightly crooked or something.  I straightened it up and made yet another print.  Still not right.  WTF?

I finally realized that I put the near perfectly symmetrical negative back in the carrier emulsion side up.  I don’t remember ever having done that before, but the emulsion side of TMax 100 film is quite shiny, so I didn’t notice it.

The five prints are pictured below with the first print (from the wrong negative) on the far right and the last (final) on the far left.  Look closely and you’ll see that two of the five are reversed.

Lynnette_Prints

Picture details:
TMax 100, 6×7 cm, RB-67 with 127mm lens, Developed in TMax RS, scan from 8×10 print on Ultrafine  VC Elite RC pearl Paper.  Shot in my very cramped unheated garage in December, 1998, long before I had a dedicated studio.

Lynnette, 1998

Lynnette, 1998

My Place

To start things rolling here, I decided to post a few pictures of my frame shop and darkroom.  I was just using up the remaining frames on a roll of film that I shot as part of a lens testing project and this turned out to be the subject of those extra frames.  Since these pictures were taken, the Besseler 67 enlarger was replaced with another Omega D5, but with a condenser head.  There are also more shelves in the darkroom for raw chemicals and books, not to mention a small sound system.

The pictures below are all taken with a Nikon F100 through a Sigma 14mm f3.5 lens on TMY2 at EI 400, developed in Xtol 1:1, and printed on Adorama 8×10 RC glossy paper.

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Frame Shop

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Darkroom — dry side

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Darkroom – wet side on left, dry side on right

Welcome to my website and photography blog

My name is Dave Krueger and I’ve been an enthusiast of black and white darkroom photography for about 50 years.  This blog is mostly just a way for me to record my activities, learning experiences, and to post pictures.  Unless otherwise posted, all the black and white images on this site are scanned from 8×10 darkroom prints.  Conversely, all color pictures are all digital unless otherwise noted.

Am a serious amateur, but don’t actively market my work nor do I do any work for hire.   I have a studio, darkroom, and frame shop making half my house is dedicated to my hobby.  Basically, I only shoot what I want to shoot and try only to satisfy my own notions of what makes a good photograph.