Sharp SG-315E cassette belt

[vampyretim]

Hi all,

I have a fault with a Sharp SG-315E Casette deck chewing tapes. The capstan belt is loose but I'm having trouble finding a replacement.

It seems to be 5 mm in width and 30 mm in length It's obviously stretched a bit.

Does anyone have any service data on this model music centre and can anyone point me in the right direction for the belt?

Many thanks,
Tim.

[ukcol]

CPC-Farnell do a good range of drive belts. Just put "belts" into their search box.

I read a good bit of advice on an American site (' can't remember which one) on ordering belts by size.

"Measure the circumference of the old belt and then deduct 5 to 10% to allow for stretch."

[sp10mk11]

The other part that can often fail on these tape decks is the take up idler that sits on the capstan shaft, they turn to goo or fall apart after so many years, you cannot get a Sharp replacement, but if mess around with various bits of tubing so you get one that fits the capstan shaft the take will start working again.
Gary

[vampyretim]

Thanks guys.

[martiR2R]

It's quite simple to make your own drive belts; sharp knife, supaglue, and O ring cord of required diameter, from, amongst others -
http://simplybearings.co.uk/shop/Sea...duct_info.html

[sp10mk11]

martiR2R
yes that's a good way of doing it, I once used some silicon petrol pipe for a model aircraft engine and that was the same slice off the size you want, I forgot about that.
Gary

[vampyretim]

Thanks guys,

Can the same be done for a flat belt?

[martiR2R]

Logically yes, you just need to source flat instead of round. How about thinking outside the box, does the belt HAVE to be flat?, 2 round belts side by side? - just a wild thought!

[sp10mk11]

The two belts could be used if the motor was a servo controlled motor so you could adjust the speeds on it, but the motor in this uses a mechanical speed governor so no easy way of adjusting the speed
You should have not trouble getting a flat belt for this though.
Gary

[vampyretim]

Hello guys,

I seem to have taken one step forward and two steps backwards.

The belt that drives the capstan has now been replaced and it did definitely need it however the take up spool still isn't moving. The capstan seems to drive another wheel with an outer rubber ring. I will as someone has already suggested experiment with some rubber tubing as it doesn't make good contact with the capstan.

At first the motor worked but now everything on the cassette deck is dead there's no power getting to the cassette deck.

Does anyone have any service data?

I'm reading a very low resistance across the motor less than ohm. I hope I haven't taken out the motor.

Many thanks,
Tim.

[sp10mk11]

Check the fuses on the power supply board

[vampyretim]

Hi again,

I replaced a fuse in the power supply which had blown but the tape deck still isn't working.

I'm measuring 42 ohms resistance across the motor and I'm getting 14V to it on both sides. It's a 13.2 v D.C motor.

I don't understand why it isn't working.

Anyone ever worked on one of these before?

Many thanks,
Tim.

[Station X]

Originally Posted by vampyretim

Hi again,

I'm measuring 42 ohms resistance across the motor and I'm getting 14V to it on both sides. It's a 13.2 v D.C motor.

Many thanks,
Tim.

Sorry if I'm asking the obvious, but is that 14V of the same polarity measured from both sides of the motor to chassis, or 14V across the motor. If the latter I'd expect it to be a faulty motor.

[sp10mk11]

I cannot remember which switch on the mech does what, you have a micro type switch and a leaf switch try measuring those to see if the power is getting through, the motor is straightforward clock wise mechanical speed governor job you really should only have 14 odd volts on the positive connector on the motor, I cannot help you with impedance reading you are getting as it ages since I worked on this tape transport.
If you were closer I would look at it for you, but diagnosing faults over the phone so to speak is not always easy.
There are regulator transistors in the power supply using zenar diodes it could be one of these has blown.

Gary

[vampyretim]

Originally Posted by Station X

Sorry if I'm asking the obvious, but is that 14V of the same polarity measured from both sides of the motor to chassis, or 14V across the motor. If the latter I'd expect it to be a faulty motor.

Thanks for taking the time to help.

I have now repaired it, I had to do a current test as I thought the motor faulty I had 45mA .

I had to rewire the supply to the cassette deck to connect to earth as both sides were of the same polarity. Once I had rewired one side of the motor to earth it sprung into life and I did my current check.

Thanks again,
Tim.

[stevehertz]

I realise that this has been running long enough to get multiple answers, but surely this is a Vintage tape section post?

[vampyretim]

Hi guys,

I'm having a lot of trouble getting the take up spool to work it's still chewing up tapes!

It seems this belt has shrunk over time and is no longer making good contact with the take up spool.

Can anyone recommend a good replacement?

Many thanks,
Tim.