Minolta X-700: A renovation project

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Andreas Thaler

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If the focus screen is not flat when inserted, its position can be corrected with the Spudger. Just try carefully.




The screen must be in its holder at the back (red arrow).

The nipple then rests on the tab and the screen clicks into place when pressure is applied (green arrow).




Now the focusing screen can be gently pressed into the tab until the nipple clicks into place.




Completed

If you look closely, you'll see that the screen is obviously tilted slightly to the right.

I looked at this on two other 700s and it's the same there.

Minolta's secret




I tried for quite some time until I found a procedure that suited me. The focusing screen remained undamaged despite some manipulation.

Only when I pressed the screen with the tip of the Spudger I did regularly slip and there were scratches. So I switched to the finger-glove method.

But no problem here, because the screen is no longer completely fresh and I have a replacement
 
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Andreas Thaler

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This video from a German colleague shows from position 19:55 how he disassembles the focusing screen. I learned a lot from it.

The language is German, but I think what is shown speaks for itself:





The X-700 had various focusing screens that could be changed, as the service manual shows. The replacement was carried out by the Minolta Service.


+++

All information provided without guarantee and use at your own risk.
 
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forest bagger

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Andreas Thaler said:
I think the sticker is just part of the camera.
Click to expand...
I don't think so - the sticker was attached after the final test in the factory.
After the first attempt to repair this sticker should be removed - especially when it is worn (as mostly after decades of use)...
 

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Chapeau! I’m impressed by your skills in camera repair AND story telling. Wonderful documentation. Serves as a role model for me doing the same when servicing an F2.
 
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Andreas Thaler

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forest bagger said:
I don't think so - the sticker was attached after the final test in the factory.
After the first attempt to repair this sticker should be removed - especially when it is worn (as mostly after decades of use)...
Click to expand...

Why should the sticker go?

I think it's pretty, they don't exist anymore, and the sticker proves that the camera was set to factory settings. That's worth a lot; in this case the settings lasted around 40 years.

By the way, this is probably an X-700 from the early series. Three tantalum capacitors and the disc that holds the ASA/Exposure compensation wheel on the camera is still made of metal and not plastic.
 
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Chan Tran

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Andreas Thaler said:
One could connect the Photoplug to a storage oscilloscope to see the curve in its entirety.

The question is whether the signal from the sensor - I assume it is a photodiode - needs to be amplified for this.
Click to expand...

You will need to connect it to a power source but in this case it's better to build it yourself buying the photodiode and mount it into something to hold it at the back of the camera.
 
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Andreas Thaler

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I'll tackle this last issue tomorrow.

I've already looked at the matter on a spare X-700.

A pawl may actually have broken off after a long period of use.

The pawl therefore holds the winding lever in the second position (winding lever extended a few degrees) against spring tension.

The pawl in the spare camera also broke off under my fingers even though it is made of metal. That's unusual. If my guess is correct, I'll replace the entire unit there.

The latch is located on the underside of this component:

 
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Andreas Thaler

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A problem that I also have in my native language, German, is the naming of the individual mechanical components of a camera.

Terms such as „lever“, „retaining ring“, „disc“ etc. are not clearly defined and therefore imprecise.

I haven't found any information about this yet, other than literature on precision mechanics.

If anyone here has a recommendation in German or English, I would be grateful.

Otherwise, one option would be to adopt the part names from the service manuals.
 
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Andreas Thaler

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Chan Tran said:
You will need to connect it to a power source but in this case it's better to build it yourself buying the photodiode and mount it into something to hold it at the back of the camera.
Click to expand...

That would once again be an exercise in electronics, which is far too rare here in DIY anyway, apart from soldering.
 
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Andreas Thaler

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Chan Tran said:
You will need to connect it to a power source but in this case it's better to build it yourself buying the photodiode and mount it into something to hold it at the back of the camera.
Click to expand...

I saw your measurement setup with a scientific/engineering HP calculator in another thread. You probably don't use a calculator like this to total up your household expenses

Is your background in electrical engineering?
 

Chan Tran

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Andreas Thaler said:
I saw your measurement setup with a scientific/engineering HP calculator in another thread. You probably don't use a calculator like this to total up your household expenses

Is your background in electrical engineering?
Click to expand...

Yes I work in the field of Industrial Automation before I retired. I rarely total my household expense but yes I use that calculator for almost any kind of calculation. I have 2 of the real calculators of the same model too but their display is so low in contrast that I found I use the emulator on the PC much more often.
 

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I remember heated discussions about those stickers even back in the 1980s. Good for me, back then I only used German cameras. Except for my Yashica Mat (which I bought new; with a sticker on it!) I had no Japanese cameras!
 
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Andreas Thaler

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Andreas Thaler:
Click to expand...
Click to expand...
The winding lever got a new spring (left) because the old one was weak. But it can no longer be locked in the unfolded position.

It's annoying, but I won't bother with it now.
Click to expand...



Tutorial: Replacement of Winding base plate B

As the winding lever can no longer be locked in the unfolded position I will replace the assembly, which, among other things, keeps the winding lever in the unfolded position. At least that's what I suspect.

It is not a serious problem, but an annoying one, especially when you want to cock the shutter in quick succession and your thumb can't find the lever.

This unit is designated „Winding base plate B“ in the Minolta service manual for the X-700.

Spare parts from a discontinued X-700 are available for this.

Let's see what's happening


Disassembly of the donor X-700





Winding base plate B is located under the frame counter.






Here is the view in the donor X-700.

I remove the assembly from this camera to replace it in my other X-700.




The winding lever is disassembled.




The number disk of the image counter rotates against a spring underneath.

Here the spring is attached to the winding base plate B ...




... and here is its mounting point on the disk.




The number disk and spring have been removed.




The washer is removed.








A spring is attached here, note the positions of its mounting points.
 
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Andreas Thaler

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The assembly holding the spring is disassembled.

Note the orange film indication filler sitting on a spring.




The filler is removed …




… as its spring is.

Winding base plate B is now accessible.

I have already removed its three screws fixing it on the case.




The mechanics underneath






Top and under of the dismantled plate.




In the meantime I have removed the winding base plate B from the X-700, which I am repairing.

You see it here on the right. The spare part is on the left.




And here's the problem, my suspicion was confirmed. This part is broken. You can see the crack.




The function can be seen here.

The clasp, which is not broken here, presses against the cam on the inner disk.

This disc is rotated on the opposite side by the winding lever, which I am simulating here with the pliers.

First position: the winding lever is folded onto the camera.




Second position: the winding lever rotates against resistance.




Third position: the winding lever clicks into place and is now unfolded.


Installing in the acceptor X-700, cleaning and lubricating



Dirt, grease residue, dry gears in the X-700 which receives Winding base plate B as a spare part.




Clean with Zippo lighter fluid best possible.

For a thorough cleaning, the mechanism would have to be disassembled or rinsed with Zippo.

I avoid this effort because the gearbox otherwise works without any problems.
 
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Sparingly lubricating with light grease.




Clean the spare Winding base plate B with Zippo lighter fluid.






The gear fell out of the plate. Now it's back in its place.




I lubricate the area around the cam with a little light grease.




Overview

Parts of the donor and acceptor (below) X-700.

I'm replacing some more parts as the spares are in better condition.




I dry clean the plastic gear because I don't know if it can tolerate solvents like isopropyl alcohol.




Then it gets some Ballistol silicone oil (which wouldn't have been necessary because I already have greased the counter gear).




Winding base plate B is installed and now the winding lever clicks into place as it should

The winding lever is temporarily installed to test the function.




The frame counter is mounted.




Two cables from the top cover have come loose from the circuit board. I solder them back on.

Since the top cover is always in the way and only hangs on the cables, this can happen.




The replaced parts.




Now the 700 works as usual

All that's missing are new light seals and mirror shock absorber.




In the Minolta service manual for the X-700 there is a separate page for the Winding base plate B with installation instructions.

In this case I found my own way.

Sometimes this is easier than working through the service manual


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Bill Burk

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Andreas Thaler said:
This means you forego a fixation point. I think that's an option.
Click to expand...

I think it’s bad form to omit a screw. A friend was showing me his Yashica TLR where the back fell off and he found former owner superglued a fake screw to one side of the back clip.

Drill and tap and put in a new painted screw.
 

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Andreas Thaler said:
1:15 p.m. (CET) in Vienna, I'm writing the first summary.

…
Dirt can only be seen along the edges of the case.
Click to expand...

I thought you would find the inside fairly clean.

WD-40 is not the penetrating oil you want.

Tri-Flow is a better choice.

Another choice is chelation. A chemical called “Evapo-rust” will dissolve the rust and leave bare metal.

They both take time.

You will want to get a set of taps, they come in vert handy
 
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Andreas Thaler

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I am talking about the edges of the case as you correctly cited.

WD-40 I have been using successfully for a long time, including for loosening screws and stuck retaining rings. It just needs time to work and no impatient users. What has worked for me in practice remains.

Under no circumstances do I use liquid rust remover in the camera because I have little control.
 
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Andreas Thaler

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Bill Burk said:
I think it’s bad form to omit a screw. A friend was showing me his Yashica TLR where the back fell off and he found former owner superglued a fake screw to one side of the back clip.

Drill and tap and put in a new painted screw.
Click to expand...

I've already explained why I did it that way.

Drilling out screws of this size, especially if they have a plastic thread, is not a good idea. The drill finds its way through the thread and not through the steel screw.
 

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WD-40 isn’t a penetrating oil. I see criticism of it online and so would encourage you to look for TriFlow.

The rust remover would be done as you currently do with lighter fluid. I’d use a swab and touch the spot. Or maybe once the body is open like now, a small putty ring around the area to make a tiny pool.
 
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Andreas Thaler

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Thank you for your comments.

All these theoretical discussions about what is supposedly better or not can be shortened by checking what actually works in practice and what doesn't.

As long as a technique gives me the desired result, I stick with it and refine the method.

So there is enough capacity left to address new problems and their solutions

But of course I'm keeping my eyes open for alternatives.
 
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Andreas Thaler

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What concerns me more are the electronic problems with the X-700, which cannot be solved by replacing the electrolytic capacitors. Things are still looking bad with solutions.
 
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Andreas Thaler

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Bill Burk said:
Another choice is chelation. A chemical called “Evapo-rust” will dissolve the rust and leave bare metal.

They both take time.

You will want to get a set of taps, they come in vert hand
Click to expand...

Of course I don't know the products in detail you recommended.

But I am and will remain a student of Thomas Tomosy


—
Thomas Tomosy, Camera Maintenance & Repair, Book 2, Amherst: Buffalo, 1997
 
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