Optiphot Biological (not Optiphot-2) stand does not power on

[ChrisR]

Your tests are giving you a "no fault found so far", but it's not an exhaustive test.

You can try the same sort of check on the bridge rec with more certainty - unplug its connections first.
You can see a "+" on one of the pictures. "-" would be opposite. Each diode in there should have tthe 0.65ish Volts you're now familiar with, one way and no conduction the other.
Things can always be different at higher voltages than your meter provides, but iof say one of them is a short, that's a result.

If you're unlucky there willl be a "shorted turn" inthe transformer which only apears at full voltage.

I'd check the BR, then
sketch out the circuit by untangling the wires, to find where the fuse is, and how the Mystery Black Thing is connected. You can check that for shorts.
Then connect up with the output side disconnected (at the BR's + and -). You can also disconnect the MBT if it's just there to reduce interference, the circuit will work without it.


MBT could be something like this - its circuit may be printed on the side:

[Smokedaddy]

Thanks ChrisR,

I appreciate you taking the time to help and offering some direction. I am going to try and fix the electrical problem but not immediately and am moving this to the back burner. I have another base (not the complete stand) coming on Monday. I was also right in the middle of making some (new to me) Rheinberg filters to experiment with. I haven't even cut/punched a single gel filter 'set' out yet but have all the material. My daughter borrowed a laminator from work that I have to get back to them on Monday. Hopefully this approach will work and I will be able to get at least one or two made. I am also in the middle of putting together a complete epi-fluorescence assembly for my Optiphot. I gathered 'all' of the necessary components over the last several months but then noticed the coupling on the epi-fluorescence illuminator was cracked and broken. Someone here was kind enough to send me another coupling which will be here Monday as well.

Thread bookmarked,
-JW:

[Smokedaddy]

Just an update. I emailed a few Nikon repair shops and Nikon asking if they might have a wiring diagram for the Optiphot Biological or Optiphot POL (they use the same base). So far one individual said they had one but said nothing more. Nikon also responded. Here was Nikon's response.

I have spoken to the tech who used to work on these and I am being told that the problem you are having was common and it was fixed by replacing the board (Revised) and transformer. Also you would need to remove the resister that is located in where the gray wiring is on the pic you sent me it has a white arrow near the front meter. None of these parts are available anymore however.


-JW:

[Smokedaddy]

confidential doc, post deleted.

[Smokedaddy]

confidential doc, post deleted.

[ChrisR]

Looks like the only part which is OK is the bridge rectifier .

But seriously, I'd chuck the lot out and replace it with a modern power supply and regulator.
If you want to convert to LED, now's the time!

It would be smaller and cooler.

[Smokedaddy]

1. To be honest, if it's fixable, I'd like to do that. My other Optiphot Biological works fine lighting wise.

2. What do you specifically mean by modern power supply for this particular scope?

3. LED, dunno, haven't used one yet. I did order one for my PZO MONTHS ago but it didn't work and the overseas seller still hasn't sent me the correct one. I was told that an LED creates a hot spot too but I haven't no direct experience of course. I saw someone selling a LED power supply on eBay. They were asking something like $350 for it. Looks nicely made though.

http://www.ebay.com/itm/LED-lamp-house- ... XQn11RfKkt

-JW:

[Smokedaddy]

... my transformer is history.

For the record ... it was confirmed by Nikon that the Nikon Optiphot-POL uses the same transformer as the Nikon Biological microscope (which is what I have).

-JW:

[Smokedaddy]

Anyone have an opinion about this retrofit?

https://www.ebay.com/p/LED-Illuminator- ... 4097.l9055

-JW:

[Pau]

I have one similar for my Zeiss.

It's well made: easy mounting, lots of light, smooth regulation and good heat dissipation. They also provide good service, mine failed well beyond warranty and was replaced. That said it also has some design issues that make it less than ideal:
- If it is like mine as I think, the LED module is a nine point array, so the light source is big and not uniform, and so it needs a diffuser at the illumination train preventing doing pure Köhler illumination.*
- The provided PWM dimmer doesn't flicker visually but it does when at reduced power in the camera LV or video. I bought from them a 21KHz model that doesn't flicker but is more expensive.
- The colour temperature (6000K) is too high for my taste, you'll need to do custom WB. 4000-5000K is preferable

In fact I do not use it anymore at least as main illuminator.

The ideal solution, and much less expensive with DIY work, is a powerful single LED placed exactly at the same position of the halogen lamp filament. Now I use a DIY solution under this idea:
- A Cree XML "neutral white" 4000K (3000mA, 10W) thermal paste glued to an aluminium heatsink. It's mounted inside a Zeiss lamphouse or at a DIY adapter (I have two)
- A LuxDrive Buckblock 2100mA driver
- A logarithmic 20K potentiometer
- A simple 12V DC power source
All the materials would cost around $30-40 **

Aside the need of DIY work (fortunately I had skilled fiends who did it) the only real issue is the intensity regulation, even at its lower set it's too bright. I solve it with a strong ND filter at the tray under the condenser.

* you can see it at http://www.photomacrography.net/forum/v ... 404#161404
** You can see a similar although much more complex system at http://www.photomacrography.net/forum/v ... hp?t=32736 , I have not the microscope at hand to take pictures

[ChrisR]

2. What do you specifically mean by modern power supply for this particular scope?

No I don't have a specific item in mind but with modern tech that should be the easier part, if you want to keep a conventional bulb.

[Smokedaddy]

I have one similar for my Zeiss.

Very creative and interesting Pau. Thanks for all the suggestions and links.

-JW:

[Choronzon]

JW, the reason you were given by Nikon in NY for the replacement of both the board and transformer is as follows. This base uses a 12V 50 W bulb. Most labs have 12V 100W bulbs around in drawers from other scopes that are common for them. When the 50 watt blows, guess what gets installed instead.
The 100W draws too much for the board and it eventually frys the board. The factory fix is to replace both transformer and board to ensure no problems down the road. Until the customer does the exact same thing a few months later. Besides, the transformer was around $200, and profit margin was high on that.
All the years I worked for the Nikon dealer, I only ever replaced about 3 transformers, but I ordered boards and rectifiers two dozen at a time.
If the transformer is internally shorted, the entire base is a write off . Time to find a doner cheap one on eBay , or an external supply. You can always go the led route, but I myself prefer the predictable QH bulb color.
If I was tethered to the Nikon system, I would upgrade to an Optiphot 2 stand with 100watt halogen. Different lamp house, but everything else fits from the 1.

[Saul]

Hi James,
I have electrical "leftovers" from the Labophot (transformer, rect. bridge, transistor, pot, wiring, not sure regarding board). If you still interested, I can ship it to you. Nothing is tested, came from the ebay purchase, "as it is"

[ChrisR]

I can understand liking the bulb, even if the heat may be undesirable.

How about finding an external DC 12V 100W supply (ebay 12V 120W about $20) and suitable separate dimmer? (dimmer eg?? ebay 162008875542 $5 wireless)