Versamet 2 High Magnification Surface Microscope

The Versamet 2 is an old Metallurgical microscope used for looking at the grain structure of highly polished sample pieces in a lab. It does this by using a type of lens that directs light at your sample and looks at the reflected image at impressively high powers for a visible light microscope.

One of the neat features is that it’s designed to take photographs of your part. The majority of the bottom half is set up to reflect the image onto a Polaroid film cartridge with an option to send the image to an attached 35mm camera. It even comes with an exposure control unit to accurately run the internal shutter.

The beauty of a reflected light microscope is that you can look at opaque objects. Vintage razor blades are a personal favorite of mine. The microscopic world is amazing in the things that you can see in a traditional microscope, but the things you can see with a reflected light microscope are that much again astounding.

Like many of my odd toys, I picked this one up at an industrial auction. Best $25 lot I’ve gotten so far.

Repairing a Canon 5D

The Canon 5D is a beautiful Digital SLR camera that retailed for far more than I’m willing to spend on a camera when it was introduced back in 2005. Fortunately with newer generations of the 5D coming out, it’s price has dropped to something more reasonable, even cheaper if it doesn’t work.
I bought a Canon 5D about 2 months ago with the interest of outgrowing my little powershot. I knew it had problems, but I thought that I would be able to fix them. For the price and the included accessories, I didn’t think I was losing out on the deal even if it was irreparable.
I tore into the camera and found nothing out of the ordinary. I spent 2 days with it in pieces on my desk and couldn’t figure it out. To the camera’s credit, it’s really well engineered and is made to be serviced.
I decided to purchase a second used camera to see if I could trace out the problem. I should be able to sell the spare camera once I’m done and make back a reasonable amount.
Which brings us to today.

The problem with Camera #1 (on the left) is that aside from the top LCD, it’s completely unresponsive. I sat the cameras side by side and checked the differences in the top LCD.
(picture)

The idea here is that Camera #2 is a “known good”. Everything seems to be functioning as it should. By swapping parts between the two cameras, I can narrow down the problem. Rather than tearing down #2 and inserting known good parts, I will be inserting the unknown parts into camera #2 to confirm function. If suddenly both cameras cease to work, then I know that I’ve both found a bad part and that #1 has multiple failures.

The first thing to do once the rear covers are off is to swap them to check the rear LCD.
Camera #2 lights up. Both LCDs are good.

What about swapping the secondary board? I thought it might be the processor board, but that requires desoldering parts to pull it out.

A swap and camera #1 is still dead. #2 responds fine.

Darn. That’s all I can do without firing up my soldering iron. I have to carefully remove the shields on the center of the processor boards. Unfortunately, the solder that Canon uses seems to melt at a higher temp than what I normally use and it takes a little time, but I manage. I’m pretty sure that it’s the processor board. Apparently that’s known for failing and I can order new ones on ebay.

At this point, Camera #1 contains known good Rear LCD, Secondary board and primary processor board and still doesn’t light up. Camera #2 functions.
Well… Shit.

The next switch comes without much hope, but I have to take off the top of the camera to access the power board so I check the top LCD and don’t see a change.

About what I expected.
The power board has 2 soldered terminals leading directly to the battery. Since my iron was still hot, this didn’t take much time. However, I did have to spend a while with some solder wick to clean the thru holes for the terminals. Swap the boards, resolder the connections, flip the switch and…

Nothing changes.

Wow. That’s almost everything I can think of. The good news was that all of the boards that I thought could be fried are actually working. The bad news is that I still don’t know where the problem is and I have to go deeper.

I wonder if I can isolate some parts by just leaving some of those ribbon cables unplugged. As I have a “known good” camera, I can start unplugging things and see what happens.

If I remove the red and black power wires from the top of the power board, camera #2 shuts off and stops working. Replace that.

Unplugging the upper 3 ribbon cables on the power board causes 3 shutter clicks on power up. Interesting.
Camera #1? 3 clicks! This is the first sign of life I’ve seen out of this outside of the upper LCD.Now I know that it’s not a jammed shutter.

There’s one more large board in there that I haven’t gotten to yet. The DC/DC converter board. This one requires some desoldering and some finicky tight cables to get out. Of the 4 soldered wires, 2 of them go to the video out port (It’s a dual function board). Since it’s an open circuit anyway, I’ll leave them disconnected for the switch.

Another swap, some soldering and crossing my fingers.

Camera #1 is working! The rear LCD is on and the top LCD shows the shots left on the CF card. Can I hope that everything works?
A press of the shutter gives a very satisfying *clickit*.

So now I’ve found the problem. The DC/DC converter board is bad. Ebay shows replacements selling for about $80. Not bad. Not great, but doable.

Let’s see what burnt out. A little finessing with my soldering iron and the shield comes off.

I don’t see anything. I did absent mindedly flick off a little piece of loose solder from one of the traces, but nothing appears burnt or otherwise shorted. I do notice a few SMD fuses on the back and pull out my multimeter to find that F103 is open. It has a little “P” on it, but I don’t know what that means.

The fuse looks like a 0603 SMD fuse. 0603 is a standard surface mount size that I use for my own boards. It’s about the lower limit of sanity for DIY. A quick check with my calipers confirms the size, but the height is really thin.

I don’t have much experience with SMD fuses so I have no idea what the “P” stands for. Google turns up this forum (http://forum.thinkpads.com/viewtopic.php?f=46&t=85680) on ThinkPads where someone  traces a backlight problem to a “P” type fuse that looks exactly like mine. They suggest a Digikey part  LittleFuse part # 0467003.NR which leads me to the Datasheet. A “P” on the fuse means that it’s rated for 3 Amps.

Digikey is my go-to source for looking up electronics so I start looking for alternatives. It seems that the majority of 0603 fuses are much taller than mine and indeed the “Littelfuse Inc” part seems to be the best match. Now we’re talking $.94 for a replacement.

Let’s see if the fuse is the only problem before we get to ordering the part.

I carefully solder some small wires to either end of F103. Any larger wires would make me nervous about tearing off a solder pad from the board. On the other end of the wires I solder in a large 3 amp automotive style fuse.

Soldering another fuse in parallel to Fuse 103.

 

 

 

 

 

 

 

 

Plug the board back in and it works! I’ve confirmed that the fuse is bad. Now to make a digikey order.

Don’t trust Amazon’s recommendations

I’ve discovered something quite misleading on Amazon.com that has been responsible for 2 failed molding attempts thus far.
When purchasing Oomoo30 from Amazon they suggest Universal Mold release.
It’s a pretty good idea. You don’t want your mold sticking to your part or the retaining walls and mold release is meant to prevent things from adhering to one another.

But while I was making my 2 part mold using Oomoo 30 silicone molding compound I discovered that the 2 halves stuck together pretty badly. I tore the halves a bit while trying to get them apart and the mold was pretty unusable. I chalked it up to inexperience. For my second attempt, I sprayed the heck out of my first mold half and let it sit for 15 minutes to dry before I hit it with a thick second coat. I wasn’t going to fall into the same trap again.

I had to tear that second mold apart in tiny chunks.

You see, it seems that Universal Mold Release is a silicone based product. And you run into a problem when you’re using a layer of silicone to prevent silicone from sticking to silicone. One of the beautiful things about silicone rubber is that it barely sticks to anything other than itself.

So buying Amazon’s recommended mold release actually had me spraying on a layer of primer, creating a better silicone bonding surface.

TL:DR
Don’t use a silicone based mold release when creating a silicone mold.