Cassette deck motor repair - part 1
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- Опубликовано: 25 авг 2020
- Repairing a 12V DC motor from a Technics RS-M250 cassette deck. These motors have a small PCB inside and it can pay to replace the capacitors on this board, and give the motor a bit of grease while you are there. This video covers getting into the motor casing and getting access to the PCB. The next video will show how to get the motor itself apart safely.
WARNING!
I'd rate this as being a pretty difficult procedure for the unskilled and there is a high probability of causing damage beyond repair. Proceed with caution!
3:40 This part helped me so much. I was confused when I went to adjust the screw and the slot felt "soft". You just have to push through the rubber opening until the screwdriver slots into the potentiometer at the bottom. Thank you for this helpful video now my $10 turntable sounds perfect!
That's great to hear. Glad you found it helpful.
You are right about the lack of videos showing motor cleaning/repairs.
I have an old Pioneer CT-200 deck with a constant run motor, one day it will go silly and i will have to take it apart.
When you said " A small punch " the ten year old part of me laughed, what a violent man :-D
Sorry silly mind :-D
Standard advice is to replace the motors, and that is actually not bad advice, but it can be expensive. Lack of appropriate stock can be an issue too. So I really wanted to see if it could be done, and done reliably. The answer is yes to both.
Great video mate. I'm currently battling with a Technics RS-M205, which looks like it uses the same motor. I replaced the belts and pinch roller, but still have that (annoying) random slow-down. The voltage drops on the 12V motor pins (at time of slow down), plus it has some squealing that I traced back to the motor bearings... All which led me to your video! I'll try some lubrication first and then maybe tackle re-capping it.
Would you recommend replacing the mainboard caps too? eg especially around the power supply
Yes, and I did a full recap of the board before messing with the motor. At a minimum do the largest power caps, and anything going to the motor. Typically they are located close together. I'd suggest doing that first, if you are chasing the weird voltage drops. Light machine oil or grease like I used can help the motor bearings, but it takes a bit to get to them, as you can see. Good luck!
@@felix_da_katze Thanks. BTW what did you use to remove the plastic pinion / pulley from the motor? A pinion puller?
From memory, I think I was able to pull it off just with fingers. The first time is a bit hard, but it does move. Try a plastic or wooden wedge if necessary.
are you able to help me for this ? i have a Matsushita MMI-6S2R2D motor and it has a exposed resistor betwheen the + and - pins, and it also has a ground pin, which is intresting, the resistor connects the + to the - pin, and when i did a test on the motor at 2V (10 volts less than its rated voltage) while wiring it up correctly according to its back, the resistor immediatly started smoking, i turned off the power to it and just wondered, why did it burnout if i wired it up correctly ??? tho, one thing for sure, its not a cascade problem, as around 10 days ago when i first got the motor, i did a 5V test and it worked fine (just lower speed due to lower voltage), so once again, why dosen't it work now ??? but now to the actual thing, do you have any ideas on how to fix that resistor problem ? in case its about remplacing the resistor : yes it is possible, just unsolder it and put a new one, that easy, but it might do it again.
It could be that the voltage is too low to get it to spin, so it turns into a dead short.
maybe you are right, but how could a resistor short circuit itself at lower voltages ? it had no contact whatsoever to the main speed regulator circuit or anything, it just connects the + to the - pin, does not even interfer with the main system, but anyways, when i have the time i will try to run it at 5V. (as i said, it worked fine when i first did a 5V test)
I have a Philips N2226 and the belt needs replacing because it disintegrated. Luckily it didn't melt, the motor cap needs replacing
HELLO EXCELLENT VIDEOS CONGRATULATIONS, I HAVE A PAIR OF RS-M 250, REPLACE THE ENGINES BECAUSE IT WAS ALREADY LOSING SPEED, AND IT IS NOT THE BELTS, WITH THIS TUTORIAL, CAN CHANGING CAPACITORS BE RECOVERED?
Not sure if I understand your question. If playback is slow and belts are good, then there is still a lot that can be wrong. It can be worth going through the entire mechanism and cleaning and regreasing everything. Check the wiring on the motor too - mine was connected through just a few strands as it had worn through over the years. Desoldered, cut and stripped the end and I had a good connection again. I replaced all the capacitors on the main PCB, but didn't make a video on it.
Amigo saludos consulta,si el motor de un radio doble casetera aiwa modelo CA w51se le daño el motor ,se podrá reemplazar por el un deck marca jvc KD A11? O tiene que ser el mismo motor del aiwa que tenía?
Muchos de los motores son muy similares, especialmente en las pletinas de cassette portátiles posteriores. Busque en el motor una etiqueta con el número de modelo; podría brindarle la información que necesita para encontrar un reemplazo.
Would this method also work on an 8 Track player? I’ve got a portable player that has that same issue where the motor won’t start until you spin the flywheel.
Maybe? Best bet is to open it up and look at the motor. If it looks similarly constructed, then you may be able to get it open. Some of the earlier compact cassette deck motors had some far more complicated circuits in the motors, which gave way to simpler IC's with just a few components.
8 tracks would be getting on to 50+ years old, so probably any oils and greases would be dried out by now, at the least.
Hello mate, what fixed the playback speed issue? Did you check the cap esr and found them to be bad or was it simply the shafts needing lubrication? Or can dirty brushes cause variations in playback speed? I guess if your going to break into the motor you might as well top up all these regardless but if it's only the lubrication issue maybe you can oil the shaft without disassembling the motor?
I think the main problem is lubrication - you need to lube the capstan bearings, and the bearings in the motor. The issue with the rear motor bearing is that it is inaccessible without taking the motor apart. Caps are replaced as they are 40+ years old so just not worth my time to test. Of course, cleaning everything doesn't hurt, and these things probably worked well for about 20 years, so I see it as a small investment in getting another 20 years out of it.
@@felix_da_katze I agree. Been having the same fluctuations in speed as you described but for now I'm just going to drop pneumatic tool oil on the shaft which will oil the top bearing and hopefully work it's way down to the lower. So far this seems to fix the problem. Thanks for the video as it helped to see the inside.
I now use a machine oil, but others recommend motor oil, or something else entirely. To be honest, almost anything would probably be better than dry bearings. The way its built, its unlikely to find its way to the rear bearing. But it is better to do what you feel comfortable with, you might get good results with just what you are doing vs ruining the motor going a step further. It is hard to get quality replacements, and the NOS I can put my hands on are more expensive than the decks I buy...
@@felix_da_katze Good point. Most of these decks were designed to be lubrication free and the last thing we want is for people to assume breaking apart a motor is required or routine maintenance. Taking care of these vintage decks is getting more difficult, even a wrong size belt can damage these motors over time. As for a the correct type of oil check out a utube channel called Project Farm, he has videos about CLP oil and NOS grease vs new formula grease. Pretty surprising the damage the wrong oil can do.
Yes, totally correct, they are basically lubrication free designs...however very likely the original design brief didn't imagine people using these 40 years later. So yeah, this would be far from routine maintenance, and I don't recommend it if you don't need to do it. In a couple of cases for me, fixed wow and flutter issues that couldn't be anything else. I really mention this for completeness for anyone following this conversation.
Yes, I have seen Project Farm and he does some pretty thorough testing.
It would help if you explained more about the type of replacement capacitors you used. Mentioning things like, non polarized vs. polarized. what the voltage values mean, and where one can purchase these capacitors. Anybody can take the motor apart fairly easy but to understand what type of electronics are needed for the replacement is the most important part of the repair that was completely passed over on your video. especially for people who are watching this in order to learn how to repair.
Each motor (so far) has had a different arrangement of caps - some have 2, some 3, and values aren't always the same (so far all have been polarised electrolytics). So you just need to open it up and replace like with like. I have a fair collection, and sometimes buy them by the bag, so usually have replacements on hand. The general rule of you can replace polarised with NP, but not the other way around most likely applies, but likely just a standard NP in there.
I typically use standard caps for everything. The only exception being replacing low esr orange caps in audio paths - thats where I spend the money, though usually those old orange caps test just fine. Some people like to use expensive Nichicon Audio Grade caps everywhere. I don't think that is a necessary spend of money, but if you are only doing a one off, so what? A couple of extra dollars on BOM won't leave you eating catfood in your retirement. Go for it. Tolerances for even GP caps these days is pretty tight, they just aren't always low esr, which isn't always a desirable or necessary trait - application it is used for, rules.
I use Nichicon, Sanyo, TK and Elna mostly, but that is just down to supply, and the fact I can buy buy the bag of 100/200 easily and cheaply. Some of the factories are literally just up the road. I drove past a Nichicon factory on my last ski trip.
@@felix_da_katze that is good to know that i can swap non polarized with polarized. Ebay sells newly upgraded non polarized caps alot so now i know i can install those. What about voltages and temperature ratings of capacitors? Are they just maximum ratings or do they need to match what was previously in the equipment being repaired?
Voltage values need to match or exceed what you are replacing, as a general rule. It can be very exciting to use under-rated caps!
Ok i understand, i will take this into consideration when i rebuild a couple of tape decks i have required. Thank you.
Mr Carlsons Lab, Dave at EEVBlog, all have channels that explain this stuff, and some good info on how to solder/desolder. Worth watching, and it's the main reason I don't go too much into it - they already explain and demonstrate it better than I could.
Couldn't you just dissasemble the motor without taking the pcb off ?
No, as you need access to the slots to be able to move the brushes aside.
@@felix_da_katze if you take it apart by the top part , you woudn't need to moove the brushes aside at all.
Unfortunately if you do that you will pull the commutator through the brushes, which will almost certainly bend or break them. That would be a bad thing. You need to pull the motor apart if you want to access the rear bearing as it is inside the plastic rear housing.
@@felix_da_katze I took it apart , removed the pulley , the comutator stayed in its place , i did not attempt to remove the back of the motor , i removed the biggest piece and left the shaft with the rotor in place , i just remove that big metal bit with the front bearing , nothing is damaged and there was no need to remove the pcb.
After that , i could EASILY move the brushes away to get the rotor off.
I see it as the safest way.
I think I know what you mean, but as I like to replace the caps, I end up having to desolder the PCB anyway, typically its just 2 posts soldered down. The only issue with leaving the PCB on, is when you reassemble you need to be careful the magnet doesn't rip the shaft through the brushes. A toothpick can help.
I really need to make a new video about this.