Sony TC366/7

[philips KT3]

I am new to the forum and feeling very lost in posting. I did this a few days ago, perhaps some kind person has already answered, but here goes again. I have six of these machines and the motors are all boiling hot. I have fitted two of them with new 2uf 250v caps but still impossible to keep my hand on the motors.

Gerard.

[Ted Kendall]

OK - a little more detail would be useful. Did any or all of them work before? It seems a little strange that six examples should all exhibit the same fault, unless there is some common cause such as poor storage or lack of lubrication. Are they set to the correct mains voltage and frequency?

[philips KT3]

Thanks Ted, my very first reply. All six are working well. Voltages are set at 240v. On the 366 models the 50/60hz switch is set to 50hz. On two of these I Have disconnected the switch, as it is used to add in the 0.5mfd part of the original cap. Now fitted new 2mfd 240v caps, but still runs very hot. Have oiled the motors' front and rear bearings, new belts etc. All machines can run all day without problems, apart from hot motors. Gerard

[Ted Kendall]

If there are two sections to the capacitor, they should both be in circuit for 50Hz, as the lower frequency requires a larger capacitance to effect the necessary phase shift. This affects the power factor and hence heat generation. That said, there is a trade-off in induction motor design between heat and radiated magnetic field, so these motors may be designed to run fairly hot in any case.

[TIMTAPE]

Is it possible you are running Sticky Shed susceptible tapes? Such tapes when not really bad might still place a bigger drag than normal on the motor, causing it to run hotter than normal. Just a thought.

[brenellic2000]

As Ted says, many tape recorder motors ran hot 'by design'.. but how hot is hot? Can you take a surface temperature reading? Is the cooling fan working and are you operating this deck vertically or horizontally? If the latter, you may be restricting the air-intake.

[philips KT3]

Thanks Ted for your expert knowledge. After many years of TV set servicing in the old analogue days I never really did study capacitor theory very much. The capacitors I have fitted to two of the TC366's are from Maplin. Brand new 2uF 250VAC. The capacitor reads 250VAC when running and the motor around 114 volts. I have looked at other members views on temperature and they say these motors do run warm, but mine are super hot. But then for a small motor at nearly half our mains power I would think it would run very hot.

[philips KT3]

Thanks timtape, all tapes are ok. I know what you mean, I have had some wonderful experience with sticky tapes screeching and even stopping the machines. I am using them vertically. Apologies in advance if I ignore any members, I am new to the forum and just learning how to post and reply.
PS.I lived in Balga in Perth many years ago, regards Gerard

[vidjoman]

I don't have the manual for this but seem to think many Japanese tape decks had 110 volt motors run via a tap on the transformer.

[Ted Kendall]

My point is that you will need 2.5uF for correct operation at 50Hz...

[philips KT3]

Yes fans working blowing out warm air. Using vertically even with front facia and backs off motor is too hot to hold. I touched the thermometer on the body as best I could an it reads 100F. The room is around 70F. I hope other members can read my replies as I am getting a few posts and don't want ignore anyone.

Thanks Ted, I was only just thinking of adding in a 0.5mfd to the 2mfd in parallel of course. Could I damage the motor, the circuit diagram says 2mfd for 50hz mains and 1.5mfd for 60hz. for other countries. Then to remove the pulley of the motor and fit the 50hz size pulley. All six machines have the 50hz size pulley. One of my machines came with the original 60hz pulley, as supplied by Sony. Think I will try adding in a 0.5mfd.Hope you are right, Gerard

Thanks vidjoman, you are correct, the service diagram shows a tap from the transformer of 100volts ac down to the motor. On the motor metal plate says 100v 50/60hz and 2mfd/ 1.5mfd. The mechanical switch on the front of the chassis is set to 50hz so as to switch in the extra 0.5mfd to the 1.5mfd on the old original capacitor. The 1.5mfd is used for 60hz in USA etc. I have disconnected the switch and fitted new Maplins 2mfd 250 volt AC caps. The motor is running around 113/114v AC and across the cap I get 240v AC. Gerard

[Ted Kendall]

OK, my mistake! If the specified value is 2uF then stick with that.

[Michael Maurice]

Did you remove both capacitors and fit the 2uF in their place or did you leave the 0.5uF in place

[philips KT3]

Hello Michael,the original caps are two in one unit,a i.5mf combined with a 0.5mf..All six sets have the same in an alloy can.I am taking these out and fitting the new 2.0mfd 240volt ac caps but the motors are still too hot to keep hold of,Gerard

[Diabolical Artificer]

Try wiring the old caps back in as they were wired when you got them. Why did you recap these? Motor run caps as fitted on these old decks are usually ok.

I'm wondering what new caps you fitted, did you by any chance use normal electrolytics instead of non polarised motor run caps?

Andy.

[philips KT3]

HI Andy,for me it was the logical thing to do.one cap was leaking the white wax,another was bumpy at the top so for the sake of £2.99 each I replaced them.they are non polarised non electrolytic.250v ac.From maplins,their number N28KG. So thought the safest thing to do,I once had a tiny cap explode on my central heating timer.The bang was similar to when I go target shooting.Why do you suggest I put the old caps back in.I wonder why no other member has reported boiling hot caps,impossible to hold the motor,Gerard

[philips KT3]

Sorry Andy ,I meant to say boiling hot motors.some of the caps were cold and some were warm when running

[Diabolical Artificer]

Hi Philip, sounds like they needed replacing and putting the old caps back would be no good.

I suggested putting the old caps back in, and wired as was to see if the motor's still ran hot. Sometimes
changing components throws up abnormal issue's, usually because of a mistake we've made. It sounds like you know what your doing.

It was the only other thing I could think of. If the motor shaft is free running and not clogged with dried grease and if the motors are correctly wired with the correct caps, then it's a puzzle.As Ted says, maybe they just run hot.

Apart from checking them with a power factor meter or a scope to check out the degree of phase I can't think of anything else.

Andy.

[philips KT3]

Thanks Andy,rather than dig out my old 35mhz double beam scope perhaps my time might be better spent in just listening to the lovely music that these old machines are producing.I have been looking at old posts re motors,made 2 or 3 years ago.including one from an expert on these tapes named doffery in blackpool.The general opinion seems that they run warm though, no mention of hot.I also have a tc399,may take the back off that and if that is hot then I presume thats the norm with sony.PS,I chose Philips KT3 because I still have a soft spot for the sets I serviced in the old cathode ray days,regards Gerard.

[philips KT3]

Thanks everyone for your advice.I now have 8 or 9 machines and all run far too hot to keep hold of, perhaps superman could. I have bought an infrared heat detector and they all run at 125F. The motors run about 114 VAC which is getting towards half UK voltage so I presume they should run hot normally. I have enjoyed making my very first post on this superb forum.

Gerard