Issue with Minolta Spotmeter M

norris47 · May 9, 2020

Hello everyone,
This is probably my first time writing in any kind of forum, so I hope to be following all guidelines.
I was hoping to find out whether any of the clever minds on this website would be able to help me with an issue I have with my recently purchased Minolts Spotmeter M. This is the newer version, so when flipping the switch to turn it on, sometimes it doesn't function (with a fresh battery in) and if I wiggle the switch a bit more and press it down a little harder the display sometimes comes on or sometimes simply flickers random shapes and numbers. I wonder if this is anything that I could fix myself and if anyone has any ideas?
Thanks
Norris

Bikerider · May 9, 2020

It looks like an issue between the switch and the printed circuit board inside.

I don't know if it is a 'do it yourself' job, but on the balance of probabilities I would say no. It may be a broken soldered connection which could be repaired, but as there is some sort of circuit finding which one is beyond me. If it was found possibly a small soldering job may work. I have done a repair of a car speedometer which was probably physically larger but even that was a tricky job despite I could see where the break was

norris47 · May 9, 2020

I am hoping to find the issue with it once I open it, a soldering job shouldn't be an issue for me, however if I don't find the fault I feel like I would struggle to find someone who can repair these in the UK.

neilt3 · May 9, 2020

Before you start dismantling anything I think you should rule out a dirty/slightly corroded contact on the switch .
Take the battery out first and squirt some electrical contact cleaner into the switch , and turn it on/off several times .
You might want to repeat this a couple of times .
Leave it ten or so minutes to evaporate , then put the battery back in and see if it's helped .

Arvee · May 9, 2020

Be super careful when opening the unit. There is a celluloid ribbon cable that is cemented to the LCD substrate and it is only secured with the adhesive. It tears loose very easily and I don't have the materials to re-attach nor the skill. Best to let a qualified service facility troubleshoot/fix.

My unit was exhibiting the same problem that you're experiencing.

Arvee · May 9, 2020

neilt3 said:
Before you start dismantling anything I think you should rule out a dirty/slightly corroded contact on the switch .
Take the battery out first and squirt some electrical contact cleaner into the switch , and turn it on/off several times .
You might want to repeat this a couple of times .
Leave it ten or so minutes to evaporate , then put the battery back in and see if it's helped .

Be careful with contact cleaner as it will melt most plastics. I destroyed a Gossen Luna Pro SBC plastic case with overspray.

norris47 · May 9, 2020

Arvee said:
Be super careful when opening the unit. There is a celluloid ribbon cable that is cemented to the LCD substrate and it is only secured with the adhesive. It tears loose very easily and I don't have the materials to re-attach nor the skill. Best to let a qualified service facility troubleshoot/fix.

My unit was exhibiting the same problem that you're experiencing.

Thank you for the advice, that is making me overthink this. Did you ever fix your meter or did you use it as is?

norris47 · May 9, 2020

Arvee said:
Be careful with contact cleaner as it will melt most plastics. I destroyed a Gossen Luna Pro SBC plastic case with overspray.

Oh wow, thank you for letting me know, I shall be very careful if I decide to use this method.

Arvee · May 9, 2020

norris47 said:
Thank you for the advice, that is making me overthink this. Did you ever fix your meter or did you use it as is?

It became a parts unit; I bought another. The individual ribbon cable/LCD contacts are responsible for the LCD segments turning off/on. I believe several of the contacts had lifted before I got in there and separated the lot. I'd have been a lot smarter if I'd left it alone and used it as long as I could correctly interpret the readings with the missing segments.

neilt3 · May 9, 2020

Arvee said:
Be careful with contact cleaner as it will melt most plastics. I destroyed a Gossen Luna Pro SBC plastic case with overspray.

That's strange . I've never heard of it causing problems .
I've used it on several cameras to clean up sticking control wheels , and other mostly plastic things where the contacts on switches were acting up .
Not seen any harm done yet .
Worth bearing in mind though .

pentaxuser · May 9, 2020

Arvee said:
Be careful with contact cleaner as it will melt most plastics. I destroyed a Gossen Luna Pro SBC plastic case with overspray.

Which contact cleaner was this and was there any warning of what could happen with plastic such as only use on switches that are not near plastic?

Thanks

pentaxuser

shutterfinger · May 9, 2020

Arvee said:
Be careful with contact cleaner as it will melt most plastics. I destroyed a Gossen Luna Pro SBC plastic case with overspray.

Sounds like brake cleaner or electric motor cleaner. Both are stronger than electrical contact cleaners. Some electrical contact cleaners are so weak that they're a wast of time to use.
CRC QD Contact cleaner and 90% Isopropyl Alcohol are what I use. I don't know what brands are available in your area. The label should state safe on most plastics and rubber.

Sometimes you can push those adhesive contact ribbon cables back down or spread the adhesive that has pushed out around the edge back over the contact area then press the cable back into position.

The switch has a dust shield on it so you will have a better chance of success opening the case and flushing the switch from inside.

Bikerider · May 10, 2020

norris47 said:
I am hoping to find the issue with it once I open it, a soldering job shouldn't be an issue for me, however if I don't find the fault I feel like I would struggle to find someone who can repair these in the UK.

As you are in England, help is at hand. If you contact the Camera Repair Workshop 9 Warfside, Bletchley, Milton Keynes, MK22AZ. Tel 01908 378088 they should be able to help you. I have had my Minolta XM serviced by them a short while back and it is as good now as when it was new. They also cleaned up my APO Rodagon as well after the iris jammed. The workmanship is very professional, quick and gets you back on the road. For a full service of my XM this cost me about £70 and took about 10 days from me posting it and getting it back via special delivery.
Not only that when Minolta went out of business to Sony they bought up all the spare parts so if they cannot sort it, then I doubt very much if anyone else can.

Arvee · May 10, 2020

pentaxuser said:
Which contact cleaner was this and was there any warning of what could happen with plastic such as only use on switches that are not near plastic?

Thanks

pentaxuser

It is Radio Shack Tuner Control Cleaner and Lubricant. It contains tetrafluoroethane, cyclomethicone and mineral oil. I don't recall when I purchased it.

Pieter12 · May 10, 2020

When I acquired a used Minolta Spotmeter F some years ago, I sent it to Quality Light Meter in Los Angeles (highly recommended, by the way). Some bad soldering connections and shorts on the circuit board were repaired.

Issue with Minolta Spotmeter M

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