Tape Project Forum
Tape Machines => Reel to Reel Tape Machines => Topic started by: sk8ter on August 16, 2013, 02:25:14 PM
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Hello. I am really embarrassed... as i have forgot how to put back together the capstan motor ..there is nothing in the service manual or pictures on the net...
The reason i took it apart to oil the bearings....well I found out that these are ball bearings! and somewhat sealed....but i did put some oil in them ..but i forget exactly how it goes back together...pictures would be nice
I am about 3/4 done with recapping the unit....I am looking forward to hearing it after all this work!
before i decided to do this work it was running good and I have a master tape someone did ...man this deck is dynamite
Thanks for your help
Lawrence
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Hey Lawrence,
Welcome to the forum.
First off, you shouldn't oil sealed bearings. They are packed with grease which helps keep the bearings quiet (learned this the hard way!).
You should probably take the motor to a bearing shop and have the bearings replaced now. The don't have to be any super duper expensive bearings but well made ones (in other words, No bearings from no-name shops overseas even if they are ceramic. Bad bearings can be made out of anything and it's more about the quality of manufacturing (Japanese or American made bearings should do great in this application).
Regarding the correct order that the motor is reassembled, I'll need to get some time to pull a spare I have apart and post later. I'm in the middle of something right now so it may be a week or so.
Maybe someone else here can get to it before me. It's been a while since I pulled the capstan motor apart.
In the future, a good idea when you take anything apart is to keep a digital camera or phone at hand. Snap pictures along the way and it can act as your digital memory (learned that one the hard way too!).
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any help with this will be greatly appreciated....yes i pulled it apart because i thought it was a plain bearing and not ball bearings ....yes i looked into replacements....IMO there is nothing really wrong with them still tight and free. i repacked them......most bearings today even abec 7 are not this good!
I did manage to put the motor back together but i am wondering if it is correct and is there some special way to orient it? there is a non metal non conductive black washer too......the motor is non functional now and the transistors that power the thing get warm within a few moments it does try to start...I hope i did not break a wire...as i am very careful I cannot tell you how upset I am now that my deck is not working....seems I have ut oh moments when i do stuff for myself!
I really messed up...
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Sometimes when you "oil" older sealed bearings, the oil will loosen up hardened grease and make the bearing "crunchy" sounding (at least, that's what happened to me).
Maybe a stupid question, but did you hold down one of the tensioners while you tested the capstan motor?
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Yes sir..I most certainly did .....several times...I took the motor back apart and looked very carefully..I have excellent close vision(I do cartridge retipping) ...I did not see any broken wires....so I am at a loss...if you would please have a look ...I cannot focus on much else until this is resolved I am crazy like that..
Lawrence
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ok you convinced me ...I bought some nsk Japan bearings...I know these are real good quality!...
anyone have more ideas on my problems...
Lawrence
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Does the flywheel/capstan assy now spin quite freely (no power, by hand) as it did prior to you taking the motor apart? If yes, then the defect has nothing to do with the bearings. If no, does it spin at all or is it just hard to turn? If no spin at all, check the spacing between the flywheel and the toothed tacho pickup that runs on the peripheral of the motor. Should be a small spacing (~1/32"). If zero, then that the problem (incorrect flywheel height).
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Hello Tim I did not take tack (metal) tooth ring off so but I do not see a spacer per say but yes the motor i can make it free turning....my question is if you have taken these apart how the washers go? is there the metal washer that is on the center race of the bearing then the large spring washer then larger washer then cir clip and on top of the cir clip is the non metal black washer?
if you would please give me a run down on how this is suppose to be?
thank you
Lawrence
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Before you get into serious troubleshooting, be sure that all fuses are good and that the machine hasn't been switched to battery power somehow.
Also, did you test the machine after re capping?
And what problems made you decide to recap?
The first thing I do when I start pulling a machine apart it to wrap the wiring harness in a way that makes more sense. I think that most machines come stock with the wires set up for the assemblers.
In other words, isolate the wires to the ones that go to the capstan motor. This makes it easier to track down electrical issues (like the one it appears you're experiencing).
Fixing this problem is going to be much easier if the capstan motor is out of the machine. It could easily be that one of the wires leading to the circuit board that pokes out of the motor unit was a little iffy and when you handled it to pull and replace the unit, it broke.
When testing, it's easiest to rig up some sort of frame that you can mount the capstan motor on. I just have an old piece of plywood that I drilled a couple of holes in and use a long bolt/nut to hold the unit. I put a weight on the other end of the wood so the capstan will hang over the edge of my table. If you don't do this, when the capstan starts turning, it'll spin off the table and that could break even more connections.
Once the capstan is secure, plug the connector back where it should be. You might as well use a tiny bit of contact cleaner on those connections just in case.
Use a piece of tape to hold down one of the tensioners.
Than one by one, wiggle the wires at both ends and see if that gets the motor going.
If that doesn't help, try the same procedure with all 3 tape speeds.
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Ok i will give it a go but I really need to find out what i wrote about above...I think somehow this has some relevance...I will do this and report back in a few..
Lawrence
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ok done this nada....I will say that the power transistors to control turn the motor get rather warm within a few 5 seconds but nothing happens(motor does not turn)
I also wanted to say if the motor is unplugged from the circuit board those transistors do not get warm!...so its in the motor I think?...if you have a readily avialable motor can you please pop the Eclip and have a look inside
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looking at the pinout on the schematic and the actual connector they do not match up! pin 1and2 have a small jumper across them there is no wire or pin on pin 3 and the rest have wires up till pin 15 but there is no pin 15 on the schematic!...whats going on here??
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Hello Tim I did not take tack (metal) tooth ring off so but I do not see a spacer per say but yes the motor i can make it free turning...
I did not say you took the tooth ring off. It is part of the flywheel and you did take that off.
I did not say there was a spacer. I asked for you to tell me the spacing between the teeth and the circuit board that picks up the signal that is generated by the teeth. I told you it should be ~1/32" or 1mm. It's it? The motor needs to be assembled to see the spacing. If you have no idea what I am talking about, I suggest you take the deck into a RTR repair specialist (this may be beyond your expertize)
I don't know the proper order of washers within the motor. To operate properly, the spacing I talked about needs to be correct. That can be affected by the washers in the motor. Also, the flywheel needs to spin quite freely. Also, is there a possibility you damaged one of the coils in the motor? Check for that.
I agree with Ironbutt. Check for broken wire between the motor and deck.
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ok Tim will do ....no this is not beyond me ...I can do most things even very small cartridge repair...
Give me a few I will get back to you again...but like i said what would cause the power transistors to warm up?
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ok I checked the spacing is about 32nd .031 and i rang out all of the wires from the plug to where they are soldered onto the board..all ring good! ok now what?
Lawrence
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Damaged coils in the motor could cause the symptoms. And I'm assuming you are correct when you say the flywheel spins freely (is not binding or impeded).
The RS-1500 series often has bad solder joints on the circuit board plugs. Re-solder the capstan motor connector (the section of the plug that is soldered to the circuit board)
I have a RS1500 in my shop for repair. When I have time, I will determine the order of the motor washers. That may not be your defect, however. Try the re-solder job first.
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ok will do thank you
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ok reflowed all the joints on the circuit board...no luck...
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Regarding the wiring of the multipin connector;
There were slight differences from machine to machine, even within the production run of RS1500 models.
I'm not sure if you have a RS1520 manual or not but there is definitely some differences between 1500 and 1520.
The bottom line is;
If the machine was working fine with the connector wired the way it is, don't change it. It may be for model changes in IC's etc..
It's probably time to get out a multimeter and make sure the correct voltages are arriving at the motor. Could be a broken conductor within the wire that you can't see.
Sometimes, if you're lucky, you can fool around with the wires where there is a bend or other obvious strain points and get it to make enough contact so the motor will turn for a second.
Just be sure and have the machine set up so it will turn when contact is re established (use some tape to hold down one of the tensioners).
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ok more updates...thanks guys I really appreciate all your time and help...
ok so i did start to check test points....no voltage at TP910 its suppose to be about 10 volts or so..i get .8volts ..something i dragging down the voltage I check with an DVM the transistors involved no shorts or anything ...suggestions...my thoughts are I will have to isolate the various transistors(desolder) one end of the feeding resistors...and see if they still bring down the voltage...
if you have some easy way ..please help
Lawrence
I still need to know the correct orientation of the washers in the motor
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You mentioned that you'd replaced some caps.
Test the power supply voltages and work your way toward the "control board". It may be a bad solder joint or even a defective cap (it happens). Also, some of the caps are polarized and it could be that one is in backwards.
As you check your voltage paths, pull each of the multipin connectors, clean the pins and reinsert them. Those connectors can get a little iffy and while it might not solve your problem, it might head off any in the future.
While you're at it, "work" the speed and timer start buttons. They are a common source of problems too.
You should always test the machine as a whole after replacing a few caps. I know it's a pain! But unless you're used to doing a lot of troubleshooting (like Tim is), it will minimize the number of things you need to check.
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You said you resoldered capstan drive board connector H. Also resolder the other connectors (I, J,L).
I'm assuming you have proper DC power going to that board (connector I)? With ground on pin 1, you should have 5V, 21V and 15V on pins 4,5,6. Also check DC on D906 (one end is ground).
Are any caps on that board leaking? Often it's a green fuzz. Very common defect.
Clean all switches on that board.
There are 8 coils in the motor. Check that all have continuity. pins 1/8, 12/9, 12/10, etc.
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ok sorry scratch my last post i forgot that the capstan motor plug has a jumper from
pin 1 to pin 2....this is what bring in the 21volt off of pin 5 on the power supply connector....
but I did check and resolderd all the connectors..this is not the issue...I also checked and rechecked all the capacitors...there was an error.... that when the unit was built they installed the wrong cap! c924 and c923 should be 33uf caps in series ...my board had a .22uf in c924 spot... so i replaced it with the correct 33uf cap...
it still may be still in the motor ....any luck or could you post the pinout so i can ring out the motor windings..my schematic is not correct or something..
Thank you
Lawrence
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As I mentioned in a previous post, the info in the manuals isn't correct for all versions/production runs of the 1500 (which I'm more familiar with).
If the machine was running correctly with the .22uF cap and now it isn't with the 33uF cap, I think that switching the cap back is worth a try.
I haven't had a chance to look at the schematic so this is just a guess.
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You need to put that .22 cap back. You said the motor worked perfectly prior to you taking it apart. Correct? Also, the board typically has the correct values (rather than the schemo).
The schemo has 12 pins for connector H. Connector H has 15 pins, so ignore pins 1-3. Pin 1 of the schemo starts at pin 4 on the connector. Check all coils now. Should range between 7.5 ohm and 25 ohm.
You did not tell me connector "I" DC power supply voltages. Are they correct?
Are there any leaking caps?
You said the motor worked after you replaced the capacitors. Correct? It only stopped working after you took it apart. Correct?
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Tim yes all the voltages on connector I are correct the 15volt measure 14v but the rest is fine...
no the motor did not work after the recap of the main control,capston and reel motor and tension control boards were redone but i cannont fine issues with them..
I did the main power supply first and everything worked fine..until i took the motor apart and or recap those boards...
I hope i answered and gave you enough to go on...
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ok no connection on pin1 and 8 brown and grey wires ....ok so this looks like the problem....suggestions please
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At first, you said the motor stopped working after you took it apart and re-assembled it.
Are you now saying the motor stopped working after you replaced the caps and took the motor apart? Big difference, BTW. You need to tell us the whole story.
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Pins 1 and 8 should be 29 ohms.. It's 3 coils in series. They are called the primary position detection coils.
There are 6 small coils on the inner ring of the motor. 3 of those are the coils in question. Likely a wire going to those coils was damaged/broken. If the coil wires look intact, start at pin 1 and keep testing with ohm meter until you find the break.
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ya Tim I found the problem and attempted to fix/solder them tiny wires...but they are just not long enough....so the question is where can i find a pair of the detection coils?
they look like they are just glued can you help
Thanks for everything..
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Those coils/pickups are custom made specifically for that motor. They are not "off the shelf" parts. Only way to replace them would be to remove ones from another RS1500 motor. That would be a lot of work. Easier just to replace the entire motor, of course. Sometimes eBay has them for sale.. Or if no motors available, buy a "parts" RS1500 deck and swap motors.
Also possible one could splice new extender wires on to the broken ones. Or, if the ends of the broken wires are not accessible (are they?), one could remove the wire entirely from the coil form and install/wind all new wire. New wire would need to be the exact same gauge as the old and the resistance would need to be close to the original coil (9.6 ohms).
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yes i was thinking on the vary same lines....wires are exposed but they are very small same size a phono cartridge wire....I will experiment tomorrow and see what i can do its too late for anything and i need to think on it..
do you have a beat up spare motor?
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I have two Technics motors in my shop, but they belong to customer units. No spares.
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Ok did the repair...very very tiny wires like in a phono cartridge! here is a pix of the repair
(http://i41.tinypic.com/zko9q8.jpg)
I do not know if it will matter but i unwound about half turn to solder them ....back together and coated them with superglue! coil reads 10ohms
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That should work.
Also re-install that .22uf cap you removed. .22 is the correct value.
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Ok that was it i just tested it! ....I really appreciate you guys help thank you!!!!
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alright for anyone who many care...I wanted to give you a follow up as i have been playing some tapes ...
I will say the recapping makes this deck IMO up there with the very very best of them....my partner has a few of the ATR machines with aria electronics..20k each and I will not be ashamed to compare :)
and ..and i still have not done the preamp sections!...
wonderful machine I really do understand why there is such a following
Lawrence
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Congrats Lawrence!
Enjoy your tapes and the music!