Question about start/run capacitors on Akai X-1810

[TommyW]

I have an Akai X-1810 that will run about 15 minutes and stop working. Motor appears to get hot. Saw a post where this is caused by the run capacitors. Looking at the unit there are three separate dual value AC capacitors. Two 3uf/1uf 260vac on each side and one smaller 2uf/1uf 260vac. I am assuming the single capacitor is the start capacitor and the other two are run capacitors. I read the dual values were for switching between 50Hz/60Hz, and I only needed to replace them with single value capacitors. Couple of questions.

1.) Looking at the attached schematic, am I making the correct assumption about the roles of these capacitors(run/start). Capacitors are highlighted in yellow.

2.) Have seen several suggestions about replacing them with ceiling fan capacitors. My concern with these are are they are cheap and will require replacement frequently.

3.) Can I just replace them with the single value capacitors for 60Hz?

Any advice or guidance would be appreciated. Thanks

 

[gadget73]

If you don't need it to be able to run at 50 and 60hz, I don't see any harm with just installing the 60hz parts and leaving the 50hz section out entirely.

They are most likely just run caps though. Start caps switch out once the motor winds up to speed, and they are usually only found on higher power motors than what lives in a tape machine. Think air compressor, bench grinder, drill press, etc. It appears they parallel the sections at 50hz and drop one out at 60.

Don't think I've ever changed a cap in a ceiling fan and the one in my bedroom has basically been turned on for 15 years at this point. I wouldn't be overly concerned about their reliability. Film capacitors are pretty durable things. Whether the form factor makes sense I can't say though.

 

[TommyW]

If you don't need it to be able to run at 50 and 60hz, I don't see any harm with just installing the 60hz parts and leaving the 50hz section out entirely.

They are most likely just run caps though. Start caps switch out once the motor winds up to speed, and they are usually only found on higher power motors than what lives in a tape machine. Think air compressor, bench grinder, drill press, etc. It appears they parallel the sections at 50hz and drop one out at 60.

Don't think I've ever changed a cap in a ceiling fan and the one in my bedroom has basically been turned on for 15 years at this point. I wouldn't be overly concerned about their reliability. Film capacitors are pretty durable things. Whether the form factor makes sense I can't say though.

Ok thanks. Although I will most likely change these while I have the unit apart, I'm not convinced the heating issue is related to the caps after doing some more investigating. After the unit has been playing for about 20 minutes, the capstan motor and take up motor get hot to the touch and start making a low noise....kinda hard to describe. Eventually the capstan motor will just stop running all together.

 

[Okke 70s]

From the snipped' it would appear to me that only C003 is a capstan motor run-capacitor. The other two appear to be related to "supply motor". Not sure if that refers to some kind of AC reel motors. They would need their own run capacitors then, probably C001 and c002.

And yes, you can replace the double run-capacitor with just the single value that you need. I did that with plenty tapemachines. You can even clean up the wiring and the swich, if you feel like it (I often thought that was neat anyway).

I have also used standard laundry machine motor capacitors. Works all the same, and can takes way more of a beating in every way then your tapemachine should ever be able to give it.

 

[Bradbrews]

Having had the run cap fail on both of my old Sony’s in the first weeks after putting them back into use I recommend doing it. Any film cap with the voltage rating will work. In fact I combined a couple to get the right value for mine. 3x 0.47 at 400v got me to a nice 1.5uF, and I doubt I would have used those old brown drop CDE’s elsewhere. Sorry for the clown color zip ties- I figured they would never be seen and it was a good way to use them up.

 

[gadget73]

If the caps are bad, the motor will get hot and make less torque so its very possibly an issue. If these happen to be those grey Japanese paper in oil caps, those are pretty terrible anyway and its easy to justify a swap.

If you haven't, try to get some oil in the bearings at both ends. Not sure if it has oil holes or not.