Problems with Omano OM36L

[CyberHeart]

I have an Omano OM36 with the rechargeable LED lamp that I'm having a couple of issues with.

The first issue is flickering of the LED. The microscope has a wheel style brightness control and at medium to high brightness the LED flickers a lot, to the point where it sometimes goes completely dark. I have checked the batteries and they are producing the correct voltage and the flickering occurs regardless of whether the microscope is plugged in or not. I'm thinking the issue is with the variable brightness switch itself. Any ideas on what is causing the flickering and how I can fix it?

The second issue is a spot in my view. Its a small spot that looks much like a piece of dust but I cannot figure out where it is coming from. I only see it through the right eyepiece when I'm using the 100x objective. It does not move when I rotate the eyepiece or when I look through the eyepiece while switching objectives. I have cleaned the eyepiece and the 100x objective multiple times but the spot remains. My hunch is that the spot is coming from dust inside the head where the light is split into the two eyepieces, but I cannot be sure. Any ideas on were the dust causing this spot may be and if it is something I can clean myself or that I need to see a professional for?

I realize the microscope I have is not very expensive and it may be worth getting a new microscope, but it is what I have and I'm not in a position right now to purchase a new one. Any advice is appreciated.

[daruosha]

The first issue is flickering of the LED. The microscope has a wheel style brightness control and at medium to high brightness the LED flickers a lot, to the point where it sometimes goes completely dark. I have checked the batteries and they are producing the correct voltage and the flickering occurs regardless of whether the microscope is plugged in or not. I'm thinking the issue is with the variable brightness switch itself. Any ideas on what is causing the flickering and how I can fix it?

The LED flickering is due to a bad brightness dimmer design/build. Adding a capacitor (or an RC low pass filter) between the LED and input voltage would fix the problem by some margins. You have to open the LED housing and add a 100uF cap on the LED input rail.

he second issue is a spot in my view. Its a small spot that looks much like a piece of dust but I cannot figure out where it is coming from. I only see it through the right eyepiece when I'm using the 100x objective. It does not move when I rotate the eyepiece or when I look through the eyepiece while switching objectives. I have cleaned the eyepiece and the 100x objective multiple times but the spot remains. My hunch is that the spot is coming from dust inside the head where the light is split into the two eyepieces, but I cannot be sure. Any ideas on were the dust causing this spot may be and if it is something I can clean myself or that I need to see a professional for?

If you see a dust particle only in one eyepiece and it doesn't rotate, remove the eyepiece and with a blower, clean the eyepiece tube. There's much higher chance for a pesky dust to enter the tube when you remove/replace eyepieces rather than inside the head between beam splitters.

[Hobbyst46]

The first issue is flickering of the LED. The microscope has a wheel style brightness control and at medium to high brightness the LED flickers a lot, to the point where it sometimes goes completely dark. I have checked the batteries and they are producing the correct voltage and the flickering occurs regardless of whether the microscope is plugged in or not. I'm thinking the issue is with the variable brightness switch itself. Any ideas on what is causing the flickering and how I can fix it

An alternative to what daruosha suggested is to leave the LED at maximum brightness, always, and add neutral density filters to reduce the brightness if needed. A small set of neutral density filters is always useful, no matter which microscope one has.

[CyberHeart]

Thank you both for your responses. I'll take a look and see if I have the capacitor in my electrical components box.

[daruosha]

Thank you both for your responses. I'll take a look and see if I have the capacitor in my electrical components box.

Use a low ESR electrolytic 100uF cap with at least 12V rating. Better to use a brand new cap from reputable brands like Panasonic, Nippon Chemi-Con, Rubycon, Elna, Nichicon, etc... Low ESR is the key since the main job of the capacitor you want is to filter high ripple current. The price difference between a one hung low made in schenzen and a name brand capacitor in low quantities are just a few cents.
Also make sure to connect the cap in the correct polarity, otherwise they release the magic smoke.

[CyberHeart]

Thank you both for your responses. I'll take a look and see if I have the capacitor in my electrical components box.

Use a low ESR electrolytic 100uF cap with at least 12V rating. Better to use a brand new cap from reputable brands like Panasonic, Nippon Chemi-Con, Rubycon, Elna, Nichicon, etc... Low ESR is the key since the main job of the capacitor you want is to filter high ripple current. The price difference between a one hung low made in schenzen and a name brand capacitor in low quantities are just a few cents.
Also make sure to connect the cap in the correct polarity, otherwise they release the magic smoke.

Thanks for the advice. I will definitely be careful to avoid the magic smoke