Rewiring microscopes and making them Brighter
Posted: Wed Jul 26, 2017 11:15 pm
I have collected more than a dozen Meiji microscopes, many of which have dead power supplies. Replacing one of them with a new Meiji power supply is beyond my resources, so I tried making my own. It was surprisingly easy. In essence,
1) I disconnected what wires I needed to, added a new plug to receive 12 V wiring, and ran the wires to the light socket (in the microscope, that is). I sometimes added a dimmer that I found on eBay and a switch to turn it on and off.
Finding an adequate power supply was easy: 12 V and 50 W or more will do the trick. Again, on eBay.
2) The whole thing cost less than $100, and so far has worked well.
3) I have some microscopes with illuminators both on the top and bottom. This required me to drill a hole in the base at some out-of-the-way position, add a switch to the circuit, so I could switch between them.
So far, it works well. I wouldn't try to sell it to a University research lab; but if it stops working, I can fix it. Since it's only 12 V DC, there's little worry for safety. I've re-done four or five so far (which will be for sale at some point) with no trouble.
MORE LIGHT!
Many of the things I look at won't transmit light; they must be illuminated from the top. The problem with this kind of illumination is that it may not work well with subjects of low reflectivity. Normally, Meiji uses 30 W 12 V halogen bulbs in the smaller lamp houses. This may not be enough.
But the microscope manufacturer wants the bulb that will last 10,000 hours! I'd not mind changing one every 100 hours if needed. So I took out a regulated power supply and tried running the bulb at higher voltages: the 12 V bulb even worked at 24 V without exploding. Fifteen to 17 V gave almost as much light, and may let the bulb live longer.
Even if it is a bit unconventional, increasing the light output by increasing the voltage seems to work. The obvious worries that the lamp housing will become dangerously hot or the wiring will melt so far are unfounded. But no one should be complacent about it.
Does anyone else have experience replacing the power supplies on-the-cheap? I'd like to know if there are problems I haven't thought of, or solutions to these problems, or yet, better approaches than mine to increasing the brightness.
1) I disconnected what wires I needed to, added a new plug to receive 12 V wiring, and ran the wires to the light socket (in the microscope, that is). I sometimes added a dimmer that I found on eBay and a switch to turn it on and off.
Finding an adequate power supply was easy: 12 V and 50 W or more will do the trick. Again, on eBay.
2) The whole thing cost less than $100, and so far has worked well.
3) I have some microscopes with illuminators both on the top and bottom. This required me to drill a hole in the base at some out-of-the-way position, add a switch to the circuit, so I could switch between them.
So far, it works well. I wouldn't try to sell it to a University research lab; but if it stops working, I can fix it. Since it's only 12 V DC, there's little worry for safety. I've re-done four or five so far (which will be for sale at some point) with no trouble.
MORE LIGHT!
Many of the things I look at won't transmit light; they must be illuminated from the top. The problem with this kind of illumination is that it may not work well with subjects of low reflectivity. Normally, Meiji uses 30 W 12 V halogen bulbs in the smaller lamp houses. This may not be enough.
But the microscope manufacturer wants the bulb that will last 10,000 hours! I'd not mind changing one every 100 hours if needed. So I took out a regulated power supply and tried running the bulb at higher voltages: the 12 V bulb even worked at 24 V without exploding. Fifteen to 17 V gave almost as much light, and may let the bulb live longer.
Even if it is a bit unconventional, increasing the light output by increasing the voltage seems to work. The obvious worries that the lamp housing will become dangerously hot or the wiring will melt so far are unfounded. But no one should be complacent about it.
Does anyone else have experience replacing the power supplies on-the-cheap? I'd like to know if there are problems I haven't thought of, or solutions to these problems, or yet, better approaches than mine to increasing the brightness.