Minolta Auto Winder G: Service and repair

Andreas Thaler

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My next main project will be service and repair for the Minolta Autowinder D and G as well as the Minolta Motor Drive MD-1.

The topic follows on from my previous work and articles on Minolta X here.

The D Version is for Minolta XD, the G version for Minolta X/XG and the MD-1 for Minolta X/XG-M.


Well-used and sometimes faulty

The winders are often offered in well-used condition and either show complete failures, malfunctions or resinous gearboxes.

Of course, corrosion damage caused by leaking battery acid is also a common issue. The fate of many devices that are no longer used and whose batteries have been forgotten over the decades.



Strong but also vulnerable partners for Minolta XD and X/XG/XG-M: Minolta winders G and D and Minolta Motor Drive MD-1


The motor drives are more complex and, in my experience, less prone to failure.

All together they are solid devices, the chassis and transmission parts are mainly made of metal.

I am pleased that I was able to find the service manual from Minolta for the Auto Winder D and G and that I also have an article about the G version in an SPT Journal edition, which is largely identical to the D version.


Winders and motors are beautiful electromechanical devices

with considerable electrical power and partly already digital control.

Their technology is anything but simple, but it should be possible to make further progress in understanding it, also when it comes to the cooperation/communication between winder - motor - camera, which is partly implemented electronically and partly mechanically.

I would be happy to receive reports of experiences and problems with these devices in advance so that we can cover the topic as broadly as possible.

But first I will do another long announced project
 
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Andreas Thaler

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I have collected a stock of - hopefully - defective winders and motors, so there is enough study material available.

Nevertheless, I ask for descriptions of the issues with your devices so that we can incorporate them into the sessions.
 
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Andreas Thaler

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Of course, memories or assumptions are also permissible.

I want to get as much out of the topic as possible.
 
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Andreas Thaler

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Am I really the last person who is too lazy to cock his camera himself?

Well, I'm excited to see where the journey will lead.

I see two options for cleaning resinous gears:
  1. complete disassembly, cleaning in lighter fluid, reassembly and lubrication.
  2. Clean with lighter fluid when assembled, move through by short-circuiting the motor, blowing out the lighter fluid/oil emulsion and lubricating.
However, caution is required here to ensure that the battery voltage does not cause ignition.

Nothing should actually happen if the lighter fluid is applied sparingly to the gearbox and remains there until it evaporates.

Still, I have to be careful. It's all too easy to forget that you're working with highly flammable solvents.
 
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Andreas Thaler

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Electronic problems should be resolvable.

I have seen so far discrete electronic components in the devices that can be replaced with off-the-shelf parts.

A logic gate is installed in the MD-1 (NOR), which can be replaced if necessary by an equivalent TTL component (transistor transistor logic).

Battery acid damage should be manageable by cleaning and, if necessary, rewiring and repairing the contacts.
 
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Andreas Thaler

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I don't think it's likely that the mechanics/motor are so worn out that parts need to be replaced. The metal parts are too solid for that and winders/motor drives for amateurs use should hardly have been exposed to long-term stress.

All in all, I see a nice electromechanical project with chances of success
 

PilotJosh357

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I'd love to get a copy of this! I had a member on another forum send me 3 non-functioning ones and it seems this service manual is near-impossible to find
 
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Andreas Thaler

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xkaes

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Thanks for posting this. The good news is that even if the autowinder cannot be repaired, you can usually find these for about the price of shipping.

Here are two additional points.

Let's not forget about the hard to find Minolta Auto Winder GP (#8731-290). It's the same as the Auto Winder G, but powers the camera meter as well as the film advance with a probe that fits into the battery chamber.

Also, several companies made copies of the Auto Winder G, under the labels Kalimar, Spiratone, etc., and some others (Centon, Seagull, Soligor, etc.) added additional features (continuous & single shot advance, cable release connection, time delay, etc.)

Your advice will probably help with repairing these as well.

 
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Andreas Thaler

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I own all of the winders mentioned, including the one with the nose for the battery chamber.

It will be an exciting journey.

Nobody should think that it's just a motor that turns. There's a lot of clever mechanics and control electronics in there.

You have to approach it with humility as always
 

Laurent

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Looks like you're not alone in this journey... I've been foolish enough to acquire a batch containing a Motor MF for my F1(s), which also contained 4 winders for the A series cameras, plus some other stuff I'm currently reselling as I have no use for it.

The cool thing is I virtually and practically got a free Motor MF and the winders for the A series...
The less cool thing is I have more work on my plate...
 
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Andreas Thaler

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Wonderful!

First I have to do the Leica R3 MOT with its capacitors, then let's move on to the motors!
 

Laurent

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I needed a quick win yesterday, so I opened a Canon Winder A. Quick win indeed, as the issue was (quite expected) the negative cable that was dead.

However, there's a lot to learn in disassembling such a winder (not to mention the reassembly challenge) so I think I'll make a short thread.

When I have remounted everything I guess, this will be more interesting . NORMALLY I did not loose any of the ball bearings...
 
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Andreas Thaler

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The winders and motor drives that I have opened so far are very cramped. Cables in particular are very short.

Always a challenge.
 

Laurent

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This one is more or less OK, but there's not a lot of spare cable. It needed a full disassembly (well, almost) simply to get to reinsert a new cable properly.
 
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Andreas Thaler

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Here we go!

Several Minolta winders and motor drives are waiting to be checked, serviced and repaired.

Here I will be sticking closely to the Minolta repair manual, as it shows details about the mechanics and electronic circuitry of the winders that are - still - understandable.

In contrast to the associated X-cameras, whose electronics are already highly integrated and therefore remain largely unknown.

With the winders, I suspect primarily electrical contact problems and of course damage caused by leaking battery acid.

In any case, a nice project that will be thematically rich
 
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Andreas Thaler

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A look at the service manual

To familiarize myself with the technical aspects of the two Autowinders D and G, I looked at the Minolta service manual.

The mechanics and electronics are discussed in detail, and adjustment procedures are described.

This gives me a rough idea of how the winder works, although understanding all the processes requires a lot of study.

Even an apparently simple accessory like a winder is a complex device and nothing is self-explanatory.

But I'm used to that now, and when it comes to repairs, you need more practical skills than those of an engineer. The former is my goal.


Electronics

As far as the electronics are concerned, no IC is installed.

Discrete components such as transistors, resistors, capacitors, potentiometer, diodes, LED and a thyristor should be easy to obtain as new spare parts.

I would remove the motor and relay from an abandoned winder if necessary.

Here is the circuit diagram for the Autowinder D:




Mechanics

Here I will limit myself to understanding how the driving force of the motor is transmitted to the camera and which mechanical components are involved:




Troubleshooting

The troubleshooting instructions with decision diagrams are interesting for my purposes.

Here are the errors that are addressed:




This should prepare me for work.


The next step

is to select the most battered Autowinder D from my collection and open it up to examine its inner workings.

If it doesn't work, I'll already have the first patient on the work table.
 
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Andreas Thaler

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SPT Journal

Larry Lyells doesn't let us down this time either.

In the SPT Journal March/April 1983, he wrote a three-page article about the Minolta Autowinder G, which is said to be largely identical to the D version.

Here, as always, he goes into detail about the functionality, mechanics and electronics.



SPT Journal: March-April 1983

Society of Photo-Technologists Journal
learncamerarepair.com


Opening the winder should not be critical, we'll take a look at it at the work table.

Stay tuned
 
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Andreas Thaler

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Minolta Autowinder G: Winder cocks the shutter but does not stop





I'm starting with a Minolta Autowinder G because I have the article in the SPT Journal by Larry Lyells with detailed technical information.






The small metal pin that stabilizes the winder on the camera is missing from the winder.

I don't know if the pin is also an electrical contact. My documents will answer that for me.




After cleaning all contacts with electronic cleaner, attaching it to an Minolta X-700 and powering on, the winder cocks the shutter but then continues to run. It is possible to release the shutter.

So I start troubleshooting.
 
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Andreas Thaler

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Suspected contact problems and a leaking electrolytic capacitor

I look at the troubleshooting section in the service manual to see if the error is described.

There is a reference to contact problems with a switch and camera contact, but in my case it is not clear. I cannot find it in Larry Lyells either.

After shorting this contact and pressing the switch, the motor responds with continuous and then single operation. This corresponds to the information in the service manual. It is not clear which of the two operating modes is the correct one.

I decide to open the winder and look at the circuit board. Maybe I will find the problem with the contact and switch.




Removal of the self-adhesive leatherette.

Now the screws underneath can be loosened.






The upper cover plate is additionally fixed with two clamps.






The cover plate can now be removed. The underside of the circuit board is exposed.




This electrolytic capacitor is leaking. Leaked electrolyte is visible at its terminals. It must be replaced.




The two common soldering points of the electrolytic capacitor, together with a resistor.




Removing the housing.




Connections for the main switch and LED.

On the right you can see the black pin for unlocking the rewind lock of the camera with its switch.






Contacts of the switch on the top of the winder and a contact pin. This is where I will clean.




The 6 volt DC motor from Matsushita Electric, Japan. Date of manufacture is March 29, 1982.




The transmission gear for the motor. Metal and plastic gears, all in very good condition.




All set to desolder the leaky electrolytic capacitor.




Here it is.

I'm sure I can find a replacement in my stock.
 
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Andreas Thaler

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In the foreground the battery contact plate.






I have a 10uF/35V electrolytic capacitor in my stock instead of the original 10uF/16V. This will work.

However, the replacement is larger. I hope the new capacitor fits in the housing.




Fitting …




… soldering the contacts into the circuit board …



… bending in position - done.

The new electrolytic capacitor fits. The polarity is also correct.




I replace the missing pin with a screw. I cut off the screw head with the Dremel.






I use the Nejisaurus pliers to adjust the height of the screw that makes contact with the camera.

I couldn't figure out whether it's just a stabilization or also an electrical contact. So I'm asuming the latter.




I adjust the height with the pin on a second Autowinder G.


Change in status

After a few attempts, the winder now triggers image after image and no longer runs non-stop.

But it stops after a few triggers and the red LED lights up. If it is in continuous operation, it stops immediately.




This is switch S 21, which is responsible for stopping the motor.

Larry Lyells recommends cleaning the switch and its mating contact if the winder stops after a few trips. The contact can also be re-bent.

I do both and spray electronic cleaner on all detected contacts and switches.

The service manual contains adjustment instructions for the switch. I don't want to bother with that because I don't think the factory settings will change themselves.




The switch moves from right to left so quickly that I can only capture it using the slow motion function on my iPhone.




And indeed, the winder is working again as it should. Single operation and continuous operation when the trigger is pressed

I don't mind that the winder stops after a few series of continuous operation. This is fixed by switching it on and off.

Great, it paid off to stick with it


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All information provided without guarantee and use at your own risk.
 
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Andreas Thaler

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The journey continues: Capacitor damage #2

During further tests, the winder stopped and the red LED lit up. At first only sporadically and now continuously.




So I started troubleshooting again and found that the second electrolytic capacitor had also leaked.




One of its terminals on the circuit board is completely corroded and I was able to pull it off with tweezers.

This probably also explains why the winder did not run continuously during the short circuit test at idle, but only in steps. I also attribute the occasional interruptions I have already noticed to this.

Obviously it wasn't switch S 21 that was causing problems after all.

Finding a replacement for the electrolytic capacitor will be exciting; its nominal value is 4.7 uF/25 V. I'll see who offers it.

Until then, I'll take a break, which I use to find out the function of this capacitor in the circuit.

Stay tuned
 
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Andreas Thaler

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The problem with the leaking electrolytic capacitors in Minolta's X-System

I have a second Minolta Autowinder G here, which - after a very long period of inactivity - worked and then also ran non-stop.

And years ago, two of my Winder Gs stopped working for no apparent reason.

If this second Autowinder G also has leaking electrolytic capacitors, then the cause for the failure should be clear.

I'll take a look at it today and wait for the replacement capacitors that I ordered.

This means that the winders are part of Minolta's electrolytic capacitor problem, which is known from the contemporaneous and related Minolta X cameras. But the solution by replacing is relatively simple.

Minolta Capacitors

minolta capacitor, x700 capacitor, x570 capacitor, x370 capacitor, x-500 capacitor, x-300 capacitor, xg capacitor, xd capacitor, tantalum capacitor
www.678vintagecameras.ca


Based on previous experience, I would only replace the electrolytic capacitors in the Autowinder G if malfunctions occur. The leaked electrolyte can be removed from the board without causing further damage.


+++

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