Power supply substitution for old Zeiss light sources?

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hb2sbdb
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Power supply substitution for old Zeiss light sources?

#1 Post by hb2sbdb » Thu Jun 16, 2016 5:40 pm

Hi,

I'm wondering if we can use a generic power supply, such as something like this

http://www.ebay.com/itm/10A-30V-DC-Powe ... SwqBJXUIWJ

instead of the old, "original" Zeiss 12V power supply for some micorsocpe (Zeiss) light sources?

I understand that, at the minimum, we would need to modify the plug. But wondering if there are other issues?

It would be great if someone has experience and recommended a source/model. I would not mind getting the old Zeiss powersupply if they are of reasonable price, but some of them are quite expensive and for something that we don't know how much longer they will last...

And of course, there's the option we should be getting rid of these old halogens and moving to LED :)

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75RR
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Re: Power supply substitution for old Zeiss light sources?

#2 Post by 75RR » Thu Jun 16, 2016 6:33 pm

The "Adjustable Dual Digital Variable Precision 10A 30V DC Power Supply" you link to should work fine.
Can not vouch for the build quality.

Agree that Zeiss Power Supplies tend to be over valued - do not be afraid of making a reasonable offer for one.
The manufacture of these Power Supplies is LEP Ltd an American company from Scarsdale N.Y.
They made these and very similar ones for several microscope makers under contract. They are all well made.

See link for prices some Zeiss Power Supplies have sold for: http://www.ebay.com/sch/i.html?_from=R4 ... Complete=1

If you do not need to convert to LED, I would suggest you don't.
Zeiss Standard WL (somewhat fashion challenged) & Wild M8
Olympus E-P2 (Micro Four Thirds Camera)

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Re: Power supply substitution for old Zeiss light sources?

#3 Post by wmodavis » Thu Jun 16, 2016 6:43 pm

There is no reason that using a power supply other than the 'original' one is not possible as long as:

1) the power supply will supply the correct voltage and
2) the power supply can supply the required current
3) The voltage is adjustable if you want a dimmable light.

I do not know what the power (voltage, current, Wattage) the original supplied but the specifications of the bulb used should determine that.
12 Volt at 20Watts, 50Watts 100 Watts???

The power supply you link to on ebay can be adjustable up to 30 Volts and supply 10 amps of current. That supply would be capable of lighting a 12 Volt and up to 120 Watt light bulb.

A caution with that supply is that you can perhaps too easily set the voltage too high, i.e. more than 12 Volts and burn out your bulb if you are not careful.

It is a very versatile power supply and I wouldn't mind having it on my electronics workbench.

On a similar side note I just built a power supply for the vertical illuminator on my Olympus BH2 scope. It is adjustable from 0-12 Volts AC and will light a 100 Watt halogen bulb. I also added a voltmeter to it. Picture here https://drive.google.com/open?id=0BztTB ... 5XLUZEc3k0
Bill Davis
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Re: Power supply substitution for old Zeiss light sources?

#4 Post by 75RR » Thu Jun 16, 2016 7:19 pm

On a similar side note I just built a power supply for the vertical illuminator on my Olympus BH2 scope. It is adjustable from 0-12 Volts AC and will light a 100 Watt halogen bulb. I also added a voltmeter to it. Picture here https://drive.google.com/open?id=0BztTB ... 5XLUZEc3k0
Any chance of a peek inside?
Zeiss Standard WL (somewhat fashion challenged) & Wild M8
Olympus E-P2 (Micro Four Thirds Camera)

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hb2sbdb
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Re: Power supply substitution for old Zeiss light sources?

#5 Post by hb2sbdb » Thu Jun 16, 2016 8:06 pm

Thank you Bill & 75RR

I have both the Zeiss 12V 100W halogen and 60W bulb housing.

You're right that although the one I show seems to have more "bells and whistle", but I'm sure the built quality won't be as solid as the old one. Amazon has similar models and the reviews are mixed.

Also good point that we can easily increase the voltage too high with those. Most of the time, I would adjust the voltage control knobs (on an original Zeiss power supply) without looking at it (my eyes are too busy with the oculars :)

I don't think I can ever build something like that by myself. If I ever got one of those replacement, I will try to put some kind of safety stop to it (duck tape or something :mrgreen:

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Re: Power supply substitution for old Zeiss light sources?

#6 Post by gekko » Thu Jun 16, 2016 8:50 pm

For what it's worth, I agree that the power supply you link to appears to be suitable for your purpose. I also note that there appear to be current setting knobs which I assume would set the maximum current that the power supply will deliver. If so, setting the current to a safe level should protect your bulb even if you turn the voltage knob too far.

Edit: I just looked again. Specs appear excellent. That is an amazing price, and shipping (at least to the US) is free. I would definitely get it.

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Re: Power supply substitution for old Zeiss light sources?

#7 Post by wmodavis » Thu Jun 16, 2016 8:56 pm

Bill Davis
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Re: Power supply substitution for old Zeiss light sources?

#8 Post by wmodavis » Thu Jun 16, 2016 9:10 pm

And gecko is right on with his observation that that PS has a current limit adjustment which if set properly would indeed protect your bulb from over voltage as long as you did not inadvertently mis-set the current knob.

Just in case I'd recommend a spare bulb cuz I know what I'd do. I'd burn out the bulb.

Another thought on that nice ebay power supply. It is an electronically regulated DC power supply and therefore more likely to failure but that's true of any piece of electronic equipment.
I think - but don't know - that most microscope illumination power supplies are variac/transformer based. Thus electrically much simpler and less prone to failure. That is why I chose the design I did plus I already had some of the parts lying around (bigger reason).

If you get that PS please keep us updated. I think it looks nice. Likely will look nicer next to your microscope.
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Re: Power supply substitution for old Zeiss light sources?

#9 Post by Crater Eddie » Thu Jun 16, 2016 9:24 pm

Nice build Bill. Compact, tidy, and very useful.
CE
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Re: Power supply substitution for old Zeiss light sources?

#10 Post by 75RR » Thu Jun 16, 2016 9:30 pm

Thanks looks great. I take it the Powerstat 10B Variac was one of the things you had lying around?
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Re: Power supply substitution for old Zeiss light sources?

#11 Post by gekko » Thu Jun 16, 2016 9:47 pm

For an AC power supply, that is as solid and reliable as they come. And, obviously, in general a regulated DC power supply is not needed for a microscope filament lamp, and is an overkill (but nice to have). For one thing, it would eliminate horizontal bars in videos (and for some applications, e.g. measuring pA levels of current in excitable cells, it is essential in order to avoid electrical interference).

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Re: Power supply substitution for old Zeiss light sources?

#12 Post by wmodavis » Fri Jun 17, 2016 1:24 pm

75RR wrote:(and for some applications, e.g. measuring pA levels of current in excitable cells, it is essential in order to avoid electrical interference).
??? Not sure why that said it was a quote from 75RR. It was obviously from the previous post by gecko????

OK gecko I'll admit to beginner status and very limited but growing knowledge in all things microscopy related. That comment has me intrigued because I know not of what you speak. Specifically what are "pA levels of current in excitable cells"? Sounds like something interesting. Can you elaborate a bit?

And also apologies to the OP. Seems we/I have blatantly hijacked your post. But in defense I do think you got good answers to your question and I find bunny trails quite interesting.
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Re: Power supply substitution for old Zeiss light sources?

#13 Post by gekko » Fri Jun 17, 2016 1:58 pm

My apologies, Bill. I was just trying to give examples of where a regulated DC supply might be worthwhile (video recording) or essential for tungsten illumination. To try to answer your question, as you know, nerve and muscle cells (excitable cells) use very small electric currents to transmit information (and to contract in the case of muscle cells). As best as I can describe it very briefly and rather crudely, if one were to try to measure such currents, one needs to place a glass micropipette to gain access to the interior of the cell and apply voltage to stimulate the cell and measure the resulting current through the pipette, and this requires the use of the microscope (as well as a micromanipulator) to be able to position the micropipette. The following link gives a more detailed (and much more accurate) description:
https://en.wikipedia.org/wiki/Voltage_clamp
The currents I think are pretty small, in the range of nanoamps (nA, 10^-9) and picoamps (pA, 10^-12 A), and the measuring circuit (including the micropipette) needs adequate shielding from electromagnetic interference, hence the need for a regulated DC supply as well for the microscope lamp.

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Re: Power supply substitution for old Zeiss light sources?

#14 Post by Crater Eddie » Fri Jun 17, 2016 2:34 pm

wmodavis wrote: I think - but don't know - that most microscope illumination power supplies are variac/transformer based.
Not really. Many (most?) of the lamp sources that I see on scopes made in the 80's and later are electronic rather than variac based. Granted that my experience is somewhat limited.
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Re: Power supply substitution for old Zeiss light sources?

#15 Post by gekko » Fri Jun 17, 2016 2:46 pm

Crater Eddie wrote:
wmodavis wrote: I think - but don't know - that most microscope illumination power supplies are variac/transformer based.
Not really. Many (most?) of the lamp sources that I see on scopes made in the 80's and later are electronic rather than variac based. Granted that my experience is somewhat limited.
CE
I think CE is right. I think only older ones (not sure what decade, but maybe early 60's and earlier or maybe 50's and earlier-- I'm sure someone will correct me) outboard power supplies used Variacs.

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Re: Power supply substitution for old Zeiss light sources?

#16 Post by wmodavis » Fri Jun 17, 2016 3:07 pm

Well again I stand corrected on how most illuminator PSs are made. And a disadvantage of the way I made my PS is it is heavy - a little over 7 lbs. Still have to get the appropriate mating connector and add that to the box.

One thing I like about this place is its a dynamite place to learn.

And gecko thanks for the description of that technique. Likely my clamp-on ammeter will not work for that.
Bill Davis
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Re: Power supply substitution for old Zeiss light sources?

#17 Post by Brad_ » Fri Jun 17, 2016 4:57 pm

I have three supplies that look identical to your eBay model. All are dead. The first one I bought weighed fifteen pounds and worked well until I destroyed it. I crushed one of the banana binding posts when it was in storage, didn't notice the damage, turned it on and poof. My fault.

Its replacement weighed nine pounds and lasted less that ten hours. It was used to drive a 100W lamp but it was never at full power for more than a few moments, mostly at half-power or less.

The last replacement weighed in at an amazing four pounds. I almost returned it without opening the package, not believing a 300W bench supply could be built weighing almost nothing. I was right. This one has been used only to drive a little 12V 60 mm muffin fan I use to cool a 100W lamp house. The cheap fan is too noisy to run at 12V so I use 6-9V. I made the mistake of plugging in a second fan at 6V and watched the output meter drop to 2V. Now this little piggie will drive only one fan at 7V max. The instructions for this state that the load must be removed before turning the power on or off. Hardly "lab grade."

Stick with LEP. The lamps will last longer with AC and the PS will last forever.

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Re: Power supply substitution for old Zeiss light sources?

#18 Post by wmodavis » Fri Jun 17, 2016 6:29 pm

But Brad I have seen a lot of YouTube videos on how to repair those PSs. What does that say.
Buy from Amazon with return privilege or watch a video on how to fix it your self.
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Re: Power supply substitution for old Zeiss light sources?

#19 Post by Brad_ » Sun Jun 19, 2016 6:48 pm

Mentioning YouTube with the 3010D power supply motivated me to
drag my two dead boxes out of storage for play time. The third
one was a false memory of a different critter.

Considering these are consumer products, they're really well made
and easy to work on. I was surprised to find a schematic of the
linear supply (the one I broke) and I'm confident enough that I
located the problem that I have the part on order.

I'd certainly buy the linear supply again. The switching supply,
so simple and neat looking, is way beyond my comprehension and
I'd likely avoid it for that reason alone.

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Re: Power supply substitution for old Zeiss light sources?

#20 Post by billbillt » Sun Jun 19, 2016 8:52 pm

I bought one of the power supplies that you mention from Ebay... I have had very good luck so far with mine.. No trouble.. I don't know if everyone else will have this good luck..

BillT

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Re: Power supply substitution for old Zeiss light sources?

#21 Post by Rodney » Sun Jun 19, 2016 9:51 pm

Can you explain the good luck you have had with this power supply or any, Mr. b. T. ??

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Re: Power supply substitution for old Zeiss light sources?

#22 Post by billbillt » Sun Jun 19, 2016 11:14 pm

Hi Rodney,
I have used it quite a bit since I bought it last year.. It has not failed me yet.. Mostly powering up LED configurations..

BillT

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Re: Power supply substitution for old Zeiss light sources?

#23 Post by billbillt » Sun Jun 19, 2016 11:25 pm

actually I bought it on 10-14-2014...

here is a pic of it:
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