Problem with AO / Reichert / Leica Diastar 100W illuminator

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Yann E.
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Problem with AO / Reichert / Leica Diastar 100W illuminator

#1 Post by Yann E. » Thu Nov 02, 2017 6:33 pm

Hello all,

I just got hold of a very nice Reichert Diastar with trino head in excellent condition, for a good price (120€ shipped) and everything would be perfect if the built-in 100w illuminator was nice enough to provide some light :x .

The control panel consistently displays a nice-looking but rather depressing :( "0.0" no matter what the intensity setting is, and of course there's absolutely no light. As my multimeter opted for retirement about 2 weeks ago without warning I have not been able to test voltages or intensities so far, but I have been able to check quite a few things by visual inspection and using an electrician's screwdriver (the kind with a LED telling you wether there's some current going through or not). So far :
- the bulb is OK. I even tried switching it with the bulb from my Metavar, still no result
- the fuse is OK
- the power switch is OK
- the power cord is OK
- when the power is on, some current is present at both ends of the intensity setting potentiometer

the only problems I have detected so far are :
- when the power is on, some current is present at both contacts of the lamp holder, with said holder removed (seems odd to me...)
- there's NO current coming back to the power switch from the AC/DC converter unit

Has anybody got any idea ?
You can only die once, but you'll enjoy it for a lifetime...

apochronaut
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Re: Problem with AO / Reichert / Leica Diastar 100W illuminator

#2 Post by apochronaut » Fri Nov 03, 2017 12:11 am

congratulations; you've gathered up one of the truly great bargains available to microscopists on a budget. fantastic optics and a nice modular frame with which to manipulate their optical precision, with various potential systems.

electronic issues don't often come up with those. first off and it's only because you mentioned 120€ as the price, are the voltages correct? are you in Europe ? ...and is the voltage 240 or 120, for both your mains and the microscope?
sometimes such things get overlooked.

apochronaut
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Re: Problem with AO / Reichert / Leica Diastar 100W illuminator

#3 Post by apochronaut » Fri Nov 03, 2017 8:51 am

The power supply is in two sections. The power supply panel, in the black louvered housing at the back and the control board assembly, which is in the base, just forward of the socket.

Have you by-passed the POT. ? It could have failed and be limiting the current supply to the bulb.


The aluminum label on the rear of the power supply housing should have the voltage stamped on it. It's 220-240v.?

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Yann E.
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Re: Problem with AO / Reichert / Leica Diastar 100W illuminator

#4 Post by Yann E. » Fri Nov 03, 2017 11:19 am

Yes, the first thing I checked before even plugging it in was that it was indeed a 240v model. I am in France and I'm always careful with US made hardware, I made the mistake once in the past, and learnt my lesson... ;)

I have not tried bypassig the POT as it is not directly connected to the main power supply, it is connected to one of the 2 electronic boards in the base (not the one holding the digital display in the front, the one that runs along the right side, is this the control board you mentioned ?) and I am a bit hesitant to risk electronic damage considering that getting a replacement would be tricky at best...I think I can find a way though, and I will give it a try.
Quick visual inspection of the 3 electronic boards didn't show any obvious damage ("burnt" components, large cracks, etc...) and there's no lingering smell of burnt electronics, but that is as far as my testing has gone so far, I am a bit reluctant to remove the boards and inspect them for thin cracks and damaged solderings under a stereoscope but I will do it if everything else fails...

I agree that this is a fine piece of equipment, the fit & finish is nowhere as good as on my Orthoplan but everything is well made, well designed in a "function over form" way, very "rational" and apparently made of quality material. I was actually quite impressed when I opened it.
I bought it on a whim as I have a nice set of 45mm Reichert 10x, 40x & 100x phase planapos + a basic 34mm Reichert 40x 0.66 in my drawers and would like to put them to good use, possibly using my Flu-Plezy on the 34mm.
I also want to cross-test those, my set of Leitz infinity Orthoplan epi objectives and the set of Vickers epi objectives from my friend's Metallux-2 (wich is now mine although I won't keep it). I know the Reichert set is not meant to be on the Leitz stands and vice-versa but I want to run some tests to try to understand the differences between the 2 systems.
I already posted some questions on this issues, here : viewtopic.php?f=5&t=3393&sid=482e4b26f4 ... 832#p42272
and here : viewtopic.php?f=5&t=4629&p=42271#p42271
and the test will hopefully provide the answers...
You can only die once, but you'll enjoy it for a lifetime...

apochronaut
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Re: Problem with AO / Reichert / Leica Diastar 100W illuminator

#5 Post by apochronaut » Fri Nov 03, 2017 1:48 pm

Yes. the main control board is the one just forward of the plug, in the base. It would be a hard find, if it needed replacing.

You could disconnect the POT and run some tests, in order to reduce the possibility of damage.

The D.I.N. planapos will work on it but I do not know whether they are coherent with the phase condenser that was made for the Diastar. The Reichert phase objectives would have been made for instruments like the Diavar 2.
I can test that, because I have a couple of Reichert Austria phase plan achromats. The planapos would be coherent with those. The phase objectives for the Diastar were only planachros.

The 40x .66 34mm Reichert objective was likely made in Austria but conforming to the AO original infinity corrections....probably a cat.# 1023 objective. They require slightly different corrections than the later D.I.N. objectives, so in a Diastar they give some unwanted CA. They can however be used with a head from the earlier series 100, fitted to a Diastar, which contains the correct tube lens.

apochronaut
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Re: Problem with AO / Reichert / Leica Diastar 100W illuminator

#6 Post by apochronaut » Fri Nov 03, 2017 3:08 pm

Yann E. wrote: the fit & finish is nowhere as good as on my Orthoplan
Everything has to be put into perspective. In the mid-70's, an Orthoplan fitted with planachromats was about $15,000. By the time the Diastar was designed and put into production, the latter half of the 80's, Leitz had moved on to such models as the Aristoplan and the price was well north of $20,000.

Contrasting to that, in 1985 you could buy the immediate precursor to the Diastar, an AO 120 100 watt with 5 planachro objectives for less than $5,000.00. A Diastar in the late 80's was around $7,000.00 and you could buy a Reichert Polyvar, for less than an Aristoplan.

Francisco
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Re: Problem with AO / Reichert / Leica Diastar 100W illuminator

#7 Post by Francisco » Fri Nov 03, 2017 3:35 pm

I do not know the electrical circuit of that microscope but, normally, in the microscopes with 12V 100W lamps the regulation was made in the primary of transformer (electronic variac). How many cables does the transformer secondary have ?.
Some pictures of the electric plates of the microscope would be very useful

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Re: Problem with AO / Reichert / Leica Diastar 100W illuminator

#8 Post by Yann E. » Sat Nov 04, 2017 6:30 pm

Here are the pictures of the Diastar's electrical innards, details above each attached picture.

Francisco, my knowledge of electrical systems and my technical English are both limited :oops: , so I am not certain as to what you call the primary & secondary here. I hope I got it right :roll: ...
Attachments
the whole underside showing <br />A-mains plug<br />B-mains switch<br />C-mains fuse<br />D-display board<br />E-main control board<br />F-wires to lampholder
the whole underside showing
A-mains plug
B-mains switch
C-mains fuse
D-display board
E-main control board
F-wires to lampholder
Diastar-underside.JPG (168.57 KiB) Viewed 4045 times
Main control board with connectors<br />1-to potentiometer<br />2-to display<br />3-to 12V DC unit
Main control board with connectors
1-to potentiometer
2-to display
3-to 12V DC unit
Diastar-control-board.JPG (189.78 KiB) Viewed 4045 times
back of 12V DC unit showing what I believe is the primary and<br />4-cables to front of the unit
back of 12V DC unit showing what I believe is the primary and
4-cables to front of the unit
Diastar-main-rear.JPG (89.98 KiB) Viewed 4045 times
front of 12V DC board plugged-in, connectors lead to<br />B-mains switch <br />F-lampholder<br />3-main control board<br />4-primary ?
front of 12V DC board plugged-in, connectors lead to
B-mains switch
F-lampholder
3-main control board
4-primary ?
Diastar-main-front.JPG (99.17 KiB) Viewed 4045 times
front of 12V DC board unplugged, connectors lead to<br />B-mains switch <br />F-lampholder<br />3-main control board<br />4-primary ?
front of 12V DC board unplugged, connectors lead to
B-mains switch
F-lampholder
3-main control board
4-primary ?
Diastar-main-front-unplugged.JPG (102.24 KiB) Viewed 4045 times
You can only die once, but you'll enjoy it for a lifetime...

Francisco
Posts: 625
Joined: Sun May 28, 2017 11:23 pm

Re: Problem with AO / Reichert / Leica Diastar 100W illuminator

#9 Post by Francisco » Sat Nov 04, 2017 7:20 pm

Hi.
I see two power sources:
5V for the display panel composed of the components (fig.4) T1 - VR1 - CR1 ..... if the display lights up correctly.
11V for the regulator and power stage of the 12V 100W bulb composed of: 220V 12V transformer (fig 3) regulator U3 - U4 (fig 1) and, possibly, transistor-triac Q (figure 5). The reference of said transistor-triac is not observed.
If you have a tester I can show you some steps to verify the regulation-power circuit of the bulb.
The transistor-triac Q of figure 5 usually gives failures

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