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Amscope T400 lighting

Posted: Mon May 17, 2021 1:04 am
by Greg Howald
Last month I purchased a T400 from Amscope with a 20 watt halogen bulb. It's plenty bright for bright field and dark field but I do wonder about phase contrast work.
I put in a 30 watt bulb to see if it would work out ok. It did! I was somewhat amazed by this but it makes me think that any T400 or T490 with a 20 watt bulb can drive a 30 watt bulb and I thought there may be some who would like to know.
Greg

Re: Amscope T400 lighting

Posted: Mon May 17, 2021 2:13 am
by lorez2
A couple of things to consider when using a higher wattage bulb is the draw of the bulb on the circuitry and the additional heat.

lorez

Re: Amscope T400 lighting

Posted: Tue May 18, 2021 11:24 am
by Analogica
It might very well be the same transformer as in the Amscope's with a 30w halogen bulb:

Yesterday I took apart my Swift s380b.
It comes with a 1w LED, but the transformer supports 2-5 volts, 1000mA, thus making possible a 3w bulb, just what I had hoped for!
However, the LED is soldered into place, so as I have just started out in microscoping, for now I have a lot to see with the 1w, before any diy'ing on the microscope :-)

Re: Amscope T400 lighting

Posted: Tue May 18, 2021 12:56 pm
by Hobbyst46
Greg Howald wrote:
Mon May 17, 2021 1:04 am
Last month I purchased a T400 from Amscope with a 20 watt halogen bulb. It's plenty bright for bright field and dark field but I do wonder about phase contrast work.
I put in a 30 watt bulb to see if it would work out ok. It did! I was somewhat amazed by this but it makes me think that any T400 or T490 with a 20 watt bulb can drive a 30 watt bulb and I thought there may be some who would like to know.
Greg
I know someone who replaced the halogen bulb of a microscope with a higher wattage halogen bulb (outside the manufacturer's guaranteed range). The light was bright and nice for many minutes. It took an hour to melt the plastic parts around the lamp and send the illuminator and scope's base to the trash.
A halogen bulb emits a lot of heat.
Yesterday I took apart my Swift s380b.
It comes with a 1w LED, but the transformer supports 2-5 volts, 1000mA, thus making possible a 3w bulb, just what I had hoped for!
However, the LED is soldered into place, so as I have just started out in microscoping, for now I have a lot to see with the 1w, before any diy'ing on the microscope
Also with LEDs, one must remove the heat. certainly with 1-3W LEDs. For example, a common consumer superbright LED pocket torch might be destroyed by the self-generated heat, if it is being charged while turned on and lighting.

Re: Amscope T400 lighting

Posted: Tue May 18, 2021 1:24 pm
by MichaelG.
Hobbyst46 wrote:
Tue May 18, 2021 12:56 pm
Also with LEDs, one must remove the heat. certainly with 1-3W LEDs.
.
Very true ... and please remember that the heat is produced at the back of the LED ... so lamp housings designed for tungsten bulbs might not be compatible with high power LEDs

MichaelG.

Re: Amscope T400 lighting

Posted: Tue May 18, 2021 9:57 pm
by Greg Howald
I have somehow made a habit of not leaving the lamp on for prolonged periods of time and the scope is all metal with no plastic in the light path other than the filter holder. But I will be cognizant of heat build up and the possibility of electronic overload. Its an experiment after all. I may well choose to return to 20 watts.
Greg

Re: Amscope T400 lighting

Posted: Tue May 18, 2021 11:12 pm
by PeteM
The other consideration is the power supply. A 20 amp supply might well provide 30 watts, but fail much sooner under the added load.

Re: Amscope T400 lighting

Posted: Wed May 19, 2021 3:13 am
by Greg Howald
I know. I have to open things up to check, and I will before I continue. If things are ok I will report back so everyone knows the result.
Greg

Re: Amscope T400 lighting

Posted: Wed May 19, 2021 3:54 am
by PeteM
Just saw my typo - meant a 20 watt power supply.

My impression is that today's cheap imported power supplies aren't conservatively rated.

In addition, filament lamps have high inrush currents before they heat up and resistance increases. So, a nominal 20 watt bulb will initially draw far more than that. A well designed supply will have some sort of current-limiting protection circuitry for the inrush current. Whether this is present for $300 microscopes - I don't know. How it responds to a 50% overload (30 watt vs. 20 watt) - I also don't know.

Re: Amscope T400 lighting

Posted: Fri May 21, 2021 5:31 pm
by Greg Howald
The end of it.

30 watts is nice but the scope does get hot too quickly.
Although the 20 watt bulb is really not able to be centered due to design, rocking the bulb to one side and putting it as far back as possible comes very close to center and increases intensity by about 20 percent. That's just enough for me to do what ever I want to do.
Solution .... Center the bulb and leave it alone.
Greg

Re: Amscope T400 lighting

Posted: Tue May 25, 2021 9:20 pm
by GeekyWife
I have a T490B with 20 watt halogen, and I've never felt any need for more light even when doing darkfield at 400x.