SEI Comparison meter repair / conversion
Hope i've posted this in the right place.
I have a beautiful old SEI comparison spot meter. I love using it, but the calibration circuit has worn out.
I found this website http://www.textklick.demon.co.uk/sei.htm and fancy the idea of doing an LED conversion, but the website appears to be dead, and the owners e-mail does not appear to work.
Can any one help me with a simple repair / conversion or updated contact details so I can buy one of the off the shelf conversions.
Originally Posted by fotopom
The correct email address for Huw is on his home page, and is firstname.lastname@example.org, and his web site is www.huws.org.uk, but I wrote an email to him recently about the same LED conversion and he replied that he no longer offers that as there wasn't enough interest. You might try writing him anyway. Maybe my inquiry plus yours might generate more interest. On his website are service instructions, including what usually goes wrong with these meters, and I'd advise reading them. In my case, it's loss of the spot on my favorite SEI. It's flaking off. Fortunately, I have a working spare.
There are several things that can go wrong such that the ammeter doesn't indicate. It could be the rheostat, contacts, photocell, or the ammeter itself. You might want to check eBay for a "parts" meter, but make sure it's the same exact design as yours. They varied in styles and assembly a little bit over the years. Ask a lot of questions to be sure the meter works. You may be able to just swap out the parts if it's in the same serial number range.
My SEI is equipped with zone system dial (very simple) that transforms it from one of the slowest to one of the fastest spot meters to use. I depend on this meter for some night photographs.
Aloha, and good luck,
Last edited by adyphot; 01-31-2010 at 02:40 PM. Click to view previous post history.
Reason: added info.
What are the symptoms of the calibration problem on your SEI? For instance if the indicator needle doesn't reach the middle mark, it doesn't mean the bulb isn't bright enough. Mine doesn't reach the mark so I drew a new mark on a piece of touchpad screen protector and placed it over the glass (press lightly - the glass is glued in place and the glue is old).
A neat trick I found, if you have to replace the bulb, you can rub an ordinary clear bulb with sandpaper to simulate ground glass.
Meter moves but is erratic but only a little way, I have no idea how to calibrate the bulb without the meter. To make matters worse, the contacts are old (and i have cleaned them gently) and so the bulb sometimes flickers or varies in brightness from one press to the next of the button. I have taken some really good landscape pictures with wonderful shade depth using this comparison spot meter, but it needs to be consistent to be of use. Hence I was pondering the LED conversion. Unfortunately Huw has never responded to any of my e-mails (they seem to bounce back), and his circuit diagram doesn't show enough detail for a mate of mine to have a go at replicating it
Has anyone ever made an LED circuit to suit, them selves? His is colour compensated (does this matter?) and he steps up his power from 1.5v to whatever the LED needs in such a way the brightness is really consistent weather the battery is half dead or not. If i use several pen batteries to achieve 3v for the LEDs (i pinched out of our solar out door lights) they dim as the battery dies, so no better than the original bulb except for more power efficient i guess. Plus the meter is still dead so how do i calibrate? I assume meter is dead as selenium cell must be stuffed.
Last edited by fotopom; 02-13-2010 at 07:36 PM. Click to view previous post history.