Minolta X series capacitor issue

David Lyga

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There is an interesting site which discusses this problem. It is here:

https://www.678vintagecameras.ca/blog/what-was-up-with-minolta-and-capacitors

Apparently, there are two types of capacitor which can solve the problem: the original solid tantalum electrolytic capacitors (STEC) and the later aluminum liquid electrolytic capacitors (ALEC). In the ALEC, the liquid dries out after a certain amount of time, negating its ability to store electricity. Due to a great price increase in raw tantalum 40 years ago, Minolta opted to use the less worthy ALEC in many of their bodies. I understand that TODAY'S ALEC is much more robust in construction and might be a good alternative to the 'better, but more costly' STEC.

My question is this: Is there ONE workable capacitor for ALL of these Minoltas? One which would use only ONE type of capacitor? Or must we buy several types of capacitors to cover all bases? In some models (X-700) there are TWO capacitors (one in the normal place under the bottom plate and the other under the top cover). However, most models have only one under the bottom plate. If so, kindly state precise part number and best vendor website.

There is also the question as to whether one should standardize on 150uF or 220uF. On digikey.com one sees part number P954-ND. This was recommended to me by someone some time ago, but I wonder if this part services all of these Minoltas.

Please gear your answers (for both my benefit and others' who are not invested with the electronic knowledge needed to translate the technical jargon) so that a final, definitive font of information can spring forth and save the day for many of us who own these wonderful Minoltas ... but must now relegate them to 'bookshelf status'. - David Lyga
 
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4season

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Rather than P954-ND, I might try 399-4625-1-ND which is a solid tantalum surface mount capacitor. Double-check physical size before you buy, but if it fits, it's good. To install, I hold the part in place with a thin strip of adhesive tape, solder down one side of the capacitor and verify that polarity and alignment look good, then solder down the other side.

Per X700 service manual, there are actually 3 capacitors to replace in order to remedy excessive current drain problems: Two are located on the underside of the pentaprism circuit board and they're kind of a pain because a number of wires need to be unsoldered before the board can be flipped over. On X700 #1, epoxy-dipped tantalum capacitors were already installed in those locations but had failed. There were no visible signs of degradation.

Not keen on the use of aluminum electrolytic capacitors in this type of application. Should be fine if camera is protected from temperature extremes and circuits are energized periodically, but for situations where camera may only occasionally be powered up, I'll put my money on the solid tantalum parts, even at 4x the cost.
 

cmacd123

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the modern Aluminum caps are probably more long lived then the old Tant caps, and less likely to fail with a loud noise and flames. I fail to see the need to use a surface mount part, as soldering that would put extra stress in the flex circuit. Stick with a name brand like Nichicon or Panasonic and you should be good for twenty years.
 
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David Lyga

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This certainly does not look like the P954-ND

https://www.digikey.com/products/en?keywords=399-4625-1-ND
 

cmacd123

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David Lyga said:
This certainly does not look like the P954-ND

https://www.digikey.com/products/en?keywords=399-4625-1-ND
Click to expand...

no that is for a surface mount application...

in using the capacitor selector -check through hole. also look at the space you need, some of them are long and skinny, while others are short and fat. Skinny is a good thing in this application as they designed the space for tiny Tants - not even sure if they made through hole Tants any more.

the number you have quoted above is this little one
https://www.digikey.ca/product-detail/en/panasonic-electronic-components/ECE-A0GKS221/P954-ND/160534

and should be a reasonable choice. Just check that you have room for the 6 and a half mm diameter.
 
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4season

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David Lyga said:
This certainly does not look like the P954-ND
https://www.digikey.com/products/en?keywords=399-4625-1-ND
Click to expand...

No, but provided that it fits the space (and I don't have an X700 disassembled at the moment) it will work well. Have used such parts in another X700 repair with good results. Minolta X-series circuitry is already 90% surface mount, and the parts which aren't (including the original capacitors) are simply tacked to the foil traces, surface mount-style.
 

cmacd123

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err one is from Digikey .ca and one is from Digikey.com. (my fault likely since I am in Canada digikey defaults to Canadian Pricing). and as the Canadian Dolar is dependent on oil prices, it is running about 60 cents US these days.

order from .com if you are in the states.
 
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LensGrinder

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Newbee here, I just bought a X700 with the capacitor problem. If tantalum is preferred and it only comes in surface mount (SM) form, why can’t I solder wire legs to the SM capacitor and turn it into radial form. As long as the value and the voltages match is there a problem?
 

cmacd123

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Later cameras used the aluminum ones, as the price of the Tantalums ones went out of sight. Remember that their are TWO caps in the X700. and the one that is the shutter cap is up inside the body.
and yes, you COULD solder leads on a surface mount cap, But you would have to be careful to avoid shorts, and also a cold solder joint when you heat up the other end of the lead. BUT why make it hard on yourself.
 

Nicholas Lindan

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mtjade2007

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I don't believe the capacitor story the web site talks about. Yes, maybe a few Minolta cams have defective caps but I can't believe the issue is so wide spread. The symptom of the X-700 looks to me is a stuck shutter release magnet issue. I have a Contax 159MM which had the exact same problem for years, I acquired its service manual and it took me years (not everyday though) to troubleshoot its shutter release circuit. I even acquired another (working) 159MM for comparison to help troubleshooting the problem. It turned out to be a simple shutter release magnet problem. I took apart the release magnet assembly and cleaned the release magnet with Isopropryl Alcohol. The problem was fixed and it has worked ever since. What actually happened was after the shutter was fired the magnet became stuck. After another cranking to advance to the next frame the shutter will not release (because the magnet was stuck) when the user depressed the release button. The LEDs would blink but no shutter release. It's not a capacitor issue. It's the magnet that is stuck.

The Contax 159MM is a great camera, with a vertical metal blind shutter with 1/4000th of a second shutter speed. Some Contax RTS-ii also has a shutter release magnet issue. But the magnet is hidden deep inside the camera and is impossible to clean. Believe it or not, my Pentax 67-ii also had the problem once. I was able to give it a tiny drop of Isopropryl Alcohol into the shutter release magnet and it has fixed it since 15 years ago. The problem never came back.
 

Bongolia

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Hmmm. I just replaced a capacitor in a X-300. It had the standard set of problems: a working LM which switched off when the exposure button was pressed then the shot wouldn't fire and film advance wouldn't work. So I replaced the cap but the problem is the same. I replaced the existing cap which, I guess, was already a replacement (6.3v, 220uF) with an equal specification. No Joy. The 6.5v capacitor was recommended as a good replacement for the original tantalum by a reliable online source. Is there a chance that the voltage may be causing a problem? 6.5v is also the standard capacitor in the Centon DF-300 which is, basically, the X-300 made of cheaper stuff. Maybe I should have a look at the mirror magnet.
 

4season

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Bongolia said:
Is there a chance that the voltage may be causing a problem? 6.5v is also the standard capacitor in the Centon DF-300 which is, basically, the X-300 made of cheaper stuff. Maybe I should have a look at the mirror magnet.
Click to expand...

Unlikely. I'm guessing that if you changed a single capacitor under the bottom cover, your work is only partly done; there are more of the things under the top cover as well.
 

cmacd123

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Symptom of a bad cap is the camera is switched on, the LEDs light up, but when Pressing the shutter release the Lights go off and stay off until the camera is switched on and off. the Cap in question is at the bottom of the x300, 370, 500 and 570. (as well as the DF300). It is near the upper cover on a X700. the 370 and 570 are sold in different markets than the 300 and 500, but by now many have crossed the Atlantic.

Lights staying on but the camera does not fire would be he magnets I believe. A 4V cap is adequate. as the battery is only 3 volts. Also if changing the cap does not solve the problem, then magnets or electronics are next.
 

bwesso

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Im seeing mentions of a third potentially issue-causing capacitor in the mix for X700s. Working on my uncle's-- replaced the two usual suspects with presumably the right caps and am still experiencing the typical viewfinder cutout/shutter lock.

Does anyone know what this third large capacitor may be tied to operationally? From what I've read, my issue should have been resolved by replacing the capacitor near the film rewind knob, but seeing as it hasnt, im curious for other things to take a look at. Thanks
 

oschect

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I recently bought an X-370 and discovered the usual signs that the capacitor was busted (Lever not going past 30 degrees, shutter not releasing, LEDs not working properly) and after seeing that it was corroded, I followed the steps to replace it. However, after two attempts the power still won't go on, and I'm not too sure what the issue could be. The battery terminals are clean, and I'm using the right capacitor. Is it possible that the corrosion from the original capacitor is covering the negative terminal and stopping it from getting power?

IMG 0397 min — Postimages

postimg.cc
(Couldn't get the image to upload here)
 

oschect

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This was with the capacitor out so you could see the difference between the solder joints. What would the fix be for the cold solder joint?
 
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