simple question :using a power supply with higher than recommended amperage rating

[tonequester]

tonequester here.

I hope that I don't "tick" any body off with a quick question. I've already done some research on this to make sure of what I think is o.k. However, i don't want to take the chance of ruining a 30+ year old piece of technology. The device in question is a 1980 Fostex X-15 4-track recorder. Here goes. Is there any problem using
a power supply of the correct voltage rating(11-15 volts), but that is rated 1.1A, when the spec sheet calls for 350ma. MAX(my capitalization). I would think that said recorder would only (draw) it's needed amperage. The results that I found Googling the problem are in agreement with that, but all i could find was concerning computer laptops. I just like to be safer than sorry, so some validation of thus would be greatly appreciated. I found the Fostex neatly packed and forgotten in my "junk stores".
I did remember that the only thing wrong with it is a broken belt. I'm pretty sure that I can get one. I downloaded the manual yesterday, which had the specifications for the power supply, which I never had. Thanks in advance to anyone who replies. Ohm's Law I know. However there may be more considerations that I'm not aware of.
tonequester.

[JoeM]

It should be fine, as long as the voltage is correct. You dont want to use a transformer rated at lower current though. Make sure the polarity matches.

[tonequester]

tonequester here.


Thanks JoeM, for the reply. I appreciate the info on such a simple matter. I've made sure that the polarity matches. The wall-adaptor/transformer is 12v.d.c. and the recorder is rated for between 11-15 v.d.c. I figured that the recorder shouldn't "draw" more than the specified current, but the old Fostex is like new and I'd probably have a hard time
replacing it. I think I payed $50.00 for it in '81. If I could find one I doubt that it would be that cheap if it was in good working order. Many thanks for your time and effort.
tonequester.

[g1]

There are regulated and non-regulated supplies. Regulated will maintain the same output voltage regardless of the current demand (up to the max. rated current).
In the case of unregulated supplies, the rated voltage is usually at the rated current. So the unloaded voltage will be higher than the loaded voltage. For example, a non-regulated 12V supply may put out 15V unloaded, but 12V into it's normal load.
Your supply is rated for 1.1A, but you will only be using .35A, so the voltage may be higher than 12V. You should have no problem because the Fostex can take from 11 to 15V. But it's worth checking that when in use with the Foxtex, the voltage is within that window of 11 to 15V.

Edit: Sorry, I missed my whole point. In response to "using a power supply with higher than recommended amperage rating", it is always ok if you check to make sure the voltage has not risen too much due to the lighter load.

[tonequester]

tonequester here.


Greetings, g-one. Thanks for the tip. I will take your advice and check the voltage with the recorder "in use". I don't want to take the chance of "frying" the old antique.
I've actually never got to use the darned thing. i bought it for $50.00 from my guitar teacher 32 years or so ago. before I had the chance to really get it figured out, the main drive belt broke.
I put it away and comlpetely forgot about it until I ran across it a few days ago. Needless to say that after 32 years of playing I'm a little better "equipt" to use it now. I was able to download
a manual for it, so I guess I'll start tring to make use of it now. I hope that they continue to make cassettes a while longer. I didn't realize until I checked around, but they are already getting hard to find. I guess I'm just another "old schooler" left in the dust ! Thanks so much for taking the time to reply. May your projects go to plan ! tonequester.
.

[olddawg]

I would be more worried about dry caps!

[tonequester]

tonequester here.


Greetings olddawg ! You,ve piqued my interest. The power supply, which is just one of thoes wall-adaptor types is pretty new. now the Fostex 4-track is over 30 years old.
Do you think it would be a good idea to check any electrolytics out in the recorder. I'd never given any thought to that, for some reason. Like many more electronic devices from 30 years ago, it isn't hard to dis-assemble or work on. I may very well have a time getting the proper drive belt for it(I think an O-ring would suffice), but caps would be no problem. Whoever designed it really put some time into making it tech friendly. If i mis-lead you about the age of the power supply, I apologize. If you think checking the caps in the recorder would be in order,
please, give me a holler. Thanks for the reply, and good to here from you. All the best. tonequester.

[J M Fahey]

Besides old electrolytic caps, I'd worry about 30 y.o. rubber parts.
Belts come to mind, and since you will already have to replace one, maybe it pays to order spares for the others too.
Good luck.

[tonequester]

tonequester here.


Thanks JM. You have a very good point. There are actually 3 belts in the Fostex. I haven't even gotten around to finding out whether one can purchase aprts for the 30+
year old deck. I'm sure that O-rings can be found to replace the broken one and one other. However, the main drive belt is a 3/8" wide flat belt, if it goes south and I can't buy parts
I'll be "up the creek'. The way I forget and lose track of websites and info, I'll be sure to order all three if this can be done. Then all I'll have to do is teach myself how to use it from the manual. My cup runneth over with confidence ! At least it's analog. At my age analog seems to be a better match, in most circumstances. I wonder if the 30+ year old cassette that was still inside it, is still good ? I'll probably have to de-magnetize the heads. Thanks for the tip. It's written down now. HopefullyIi won't lose the notebook. Have a great day. tonequester.

[km6xz]

I would not worry about the caps, there is little heat in their environment so it is typical that they are fine. It has been pretty rare for devices that run essentially at ambient room temperatures to have deteriorated caps after only 30 years.
The rubber parts consist of 4 belts and a pinch roller. Rubber restorer will deoxidize the pinch roller unless it was left in the engaged position. It that is the case it probably has a flat spot or dent the size of the capstan.

If you hook it up, the only electrical issues likely to be concerned with would those that it had when retired from use years ago. They were actually very reliable and simple recorders. The tape spec is important in performance and finding the proper bias style might now be harder than getting the deck running.
Here is the service manual, not a great copy however but will give the calibration procedure http://www.sound-pros.com/images/fostex_x-15_sm.pdf

They were actually pretty well made and worked fine, with decent tape had a 60db s/n and less than 1%thd record/playback cycle.
Good luck.

[km6xz]

There are 4 belts, two of which, thin rubber bands are good enough replacements(mechanical turns counter belt and the belt that trips the auto stop when supply reel comes to the end of tape travel). If you have a electronics parts house near you look for some rubber restorer chemical and you might have usable belts. It was pretty easy on belts so they lasted a long time in the X-15. The equivalent Tascam's were harder on belts.
The tape is probably fine, they did not have the hydroscopic binder problem that pro tape did during that period. It is pretty rare to need to demag heads on a cassette deck, the head material and lack of DC on the heads meant it was very rarely needed.
You might find a shop with some parts but more likely you can find junkers in used music stores or Craig's List, or even eBay. Collect junkers for any old piece of gear you want to keep running for a long time.

[tonequester]

tonequester here.


Greetings km6xz ! What a great surprise. I'm printing off the service manual now. I have the owners manual, but had no luck gettng anything else. It appears that I can still get parts like the belts. I should have figured that you would be "in the know' about the X-15. I've actually had the thing in movement with a rubber band, so everything seems to be in
working order as far as mechanical drive, anyway. If I can get the old device working properly, it will add some variety to my guitar practice. I had just about figured it out when the belt broke over 30 years ago. I worked so much overtime in those days that I didn't have time to fool around with it, and soon forgot it. Somehow it survived several moves unscathed. I remember my teacher offering it to me for $50.00 like new. When he asked me if I would be interested in a 4-track player I thought he was nuts. Afterall, I had an 8-track in my car.
8 had to be better than 4. After he explained how it could be used, I had big dreams. At the time I had about 30 or 40 hours on the Takamine classical guitar which I had also bought from him. he played a custom-built classical but always had a rainy day guitar on hand because he wouldn't take the custom job out if the weather was bad. Each year he sold the rainy day special at half price to a student. I didn't realize when I bought the recorder that I would need a few more YEARS of lessons before I was good enough to worry about any multi-tracking.
I'm ALMOST good enough now. I had to give up on the classical after chopping off the finger tips of my right hand in a printing press. It made fingerstyle out of reach. However, after so many years, I am able to do a little fingerstyle with my blues. Living in the U.S. now-a-days, the blues are becoming very relevant again. I've played them for years, but now I can truly say tha tI feel them as well. Anyway, those caps sure look and feel o.k.. there are no leaks or bulges and no "crunchy" feel when squeezed by the fingers. After i bone up on the manual that you were so good to get for me, I might even give it a try with rubber band. I was lucky to have a power supply that will work. I had already wondered about the bias of the tapes. Around here, I can only find the standard tapes, and they are becoming increasingly rare. The owner's manual identifies Type II, high bias, chromium oxide under specificatioins block diagram. I'll have to Goggle to see if that type is even made anymore. I can remember that with the last Home Stereo system I purchased, the Harmon-Kardon had a Metal type selection and thats what I always used with it. They were several bucks a tape more, so I figured they had to be the best. I was already developing the American mentality. More expensive---better quality.
Now I let my ears and my heart make all decisions musical. MY friend, i didn't wish to keep you tied up to long with this post. From your recently shared pic's, I figure you have "Better Fish to Fry ! I can't thank you enough for thinking of me and the old Fostex. I hope that it's up and running before too long. At least it's analog. For some strange reason I have better luck with analog. It's not that I'm anti-digital by any means, but I am certain that digital devices have a conspiracy against me ! Have a wonderful day/night/life, enjoying the NEW AMERICAN DREAM. Sincerely, tonequester.

[Laz]

I need help as well. I pulled my x-15 out of storage and it is not working correctly. When I hit play, only the little metal spindle to the right of the play-head moves. The head moves forward to engage, and then after a second it autostops. The tape itself never moves a bit. I was able to rewind without difficulty.

I opened it up and I can only see 3 belts. The large one on the capstan. It goes to a a small spindle that has another belt that is thinner. Then a very thin belt below the capstan. Both the capstan and the 2nd belt feel loose. But they both turn and are not broken.

Any idea what is wrong with this machine?

[Enzo]

Expose the innards. Look at the capstan and see the direction it should turn. Now look underneath at the flywheel, which is part of the capstan. Turn the flywheel with your finger a ways, see if the machine will "cycle" back to home position. Sometimes just doing that clears obstructions and allows function to return.


It autostops because the tape doesn't move.


Is the motor turning?

[Laz]

Expose the innards. Look at the capstan and see the direction it should turn. Now look underneath at the flywheel, which is part of the capstan. Turn the flywheel with your finger a ways, see if the machine will "cycle" back to home position. Sometimes just doing that clears obstructions and allows function to return.


It autostops because the tape doesn't move.


Is the motor turning?

I made two videos illustrating what is going on. Turning the wheels seems to do nothing to correct the problem.
Fostex X-15 part 1 - YouTube
Fostex X-15 - YouTube