Capstan motor always on

[LJV]

Hi,

I'm up to my ears in fixing and adjusting an Sony FH-150R deck. Yes, yes... I bought one for 45 euros without speakers, got extra deck for spares, but I'm having very ugly times since first day of new year, so I haven't been in the mood to make pics and write about the find. At the moment I'm using the cleaning and fixing of it, as a way to turn my thoughts from things I can't affect.

Here is the problem - Everything works, but as long as the deck is connected together with the rest of the components (power on), the motor rotates the capstans.

All functions work fine, it plays in both directions, auto reverse works, door opens and closes, I can put in the tape in and take it out, but even when no function is engaged, capstans are rotated by the motor, and it doesn't seam logical.

It doesn't affect the function of the deck or the unit in any way, apart that it unnecessary wears away motor, belt, bearings and makes noise.

I think that it should start running when head and pinch roller are lifted to play position, but I can't seam to tell if it is some switch within mechanism that is stuck, or if it is problem with electronics which controls the unit.

Please help

Thanks in advance!

 

[ledmeter]

Hey! That's my way of making myself feel worthwhile and better sometimes too. I hope things are ok for you real soon.

Usually the motor is the first thing to begin in the deck function. It needs to be running to lift the play mech and pinch roller. So when you first press a button it sends power to the motor first which then directs the deck to the corresponding motion.
Could it be possible that the play mechanism hasn't lowered fully; leaving a contact switch engaged? Or a contact switch behind a button is still engaged?
I would be looking for the source of the power to the motor and trace it to the switches that operate it. Good luck!!

 

[LJV]

Hey! That's my way of making myself feel worthwhile and better sometimes too. I hope things are ok for you real soon.

Usually the motor is the first thing to begin in the deck function. It needs to be running to lift the play mech and pinch roller. So when you first press a button it sends power to the motor first which then directs the deck to the corresponding motion.
Could it be possible that the play mechanism hasn't lowered fully; leaving a contact switch engaged? Or a contact switch behind a button is still engaged?
I would be looking for the source of the power to the motor and trace it to the switches that operate it. Good luck!!

Thanks man. Knowing that someone understands means a lot.

I'm also suspecting that mechanism isn't lowered fully, I'll check that. It has no buttons in conventional sense, only micro switches that are connected to the circuit board. It is electronically controlled unit, and I've followed the wires that power motor - to circuit board

 

[baddboybill]

There is usually a micro switch on deck itself that when 2 leafs are connected turns on motor. Find the micro switch and look why it's always in on position. The leafs are pushed by something to lock into on position but maybe it's stuck in that position. The micro switch usually looks like this

 

[LJV]

There is usually a micro switch on deck itself that when 2 leafs are connected turns on motor. Find the micro switch and look why it's always in on position. The leafs are pushed by something to lock into on position but maybe it's stuck in that position. The micro switch usually looks like this

[ Image ]

Tried that already. That micro switch is connected directly to circuit board via tiny jack (two wires). I've unplugged it from the circuit board and nothing changed. In fact, I've unplugged all cables but one that powers the motors and mechanism, and it still kept going.

I think that unless it is some oxidation causing the bypass, than it must be the control unit (chip) problem. I've been gazing at circuit board and gently cleaning any dirt between any two soldered contacts, but no luck.

 

[LJV]

Tried whole bunch of stuff, done more cleaning - no luck.

Unless someone comes up with a solution, I think I'm going to build in a switch that will cut the power to the motor when head and pinch roller are disengaged.

I'm serious, damn thing is wrong if it thinks that I'm less stubborn opponent.

 

[baddboybill]

The switch cuts power to motor so something is causing the power traces for motor to continue. Maybe someone bridged the traces. I have had that happen on my Sanyo M X720K.

 

[baddboybill]

There are usually more than one micro switch on decks. There is also one for the heads and sometime for other options.

 

[LJV]

There are usually more than one micro switch on decks. There is also one for the heads and sometime for other options.

There are 5 more micro switches, but they react on closed/opened door, presence/absence of tape, recording safety aperture on tape etc.

I've tried and unplugged all of them from circuit board but motor keeps running.

 

[baddboybill]

Well if you know the right micro switch for motor take pics of PC board where wires go in and where motor wires go in. Something must be bridged

 

[LJV]

Well if you know the right micro switch for motor take pics of PC board where wires go in and where motor wires go in. Something must be bridged

I have the service manual in PDF. http://www.freeservicemanuals.info/servicemanuals/download/Sony/fh-150r.pdf From page 38 onwards.

The PB is almost the size of newer PC motherboards, a real nightmare.

 

[baddboybill]

Ok so which motor is always on the reel motor or the capstan motor?

 

[Superduper]

Looks like it's working normally to me. It appears that the capstan motor is always energized. Seeing as this is a AC only box and not a portable battery operated boombox, Sony probably didn't care. The capstan motor being always on and ready makes for fast logic control action (no delay). The capstan motor only turns the needle and powers the robotic functions anyhow. The actual reel motors are controlled separately. I say leave well enough alone before you mess something up which is possible. The more handling of those bare boards and cables, the more chances of introducing issues where there was none prior.

 

[LJV]

Ok so which motor is always on the reel motor or the capstan motor?

The capstan motor. I've changed the topic title to Capstan motor always on, instead of Deck motor always on, to exclude further confusion.

Looks like it's working normally to me. It appears that the capstan motor is always energized. Seeing as this is a AC only box and not a portable battery operated boombox, Sony probably didn't care. The capstan motor being always on and ready makes for fast logic control action (no delay). The capstan motor only turns the needle and powers the robotic functions anyhow. The actual reel motors are controlled separately. I say leave well enough alone before you mess something up which is possible. The more handling of those bare boards and cables, the more chances of introducing issues where there was none prior.

Indeed, even less - that motor actually does nothing but turning of those two capstans (since it is auto reverse). Everything else is done by second motor and three electromagnets which do the robotic stuff.

I agree about leaving it as is. I've already done too much disassembling and reassembling. Changing the belt only is really risky, and there is so many cables and elements that can be damaged.

Would like to hear from other similar FH owners, if their decks are also always on IDLE with rotating capstans.

BTW, should I lube plastic gears? I mean put grease on them, or leave them dry?


Big THANK YOU to all who replied here, and tried to help out, as well for those who are yet to do it.

 

[SONY FH-150R]

Hi,

I'm up to my ears in fixing and adjusting an Sony FH-150R deck. Yes, yes... I bought one for 45 euros without speakers, got extra deck for spares, but I'm having very ugly times since first day of new year, so I haven't been in the mood to make pics and write about the find. At the moment I'm using the cleaning and fixing of it, as a way to turn my thoughts from things I can't affect.

Here is the problem - Everything works, but as long as the deck is connected together with the rest of the components (power on), the motor rotates the capstans.

All functions work fine, it plays in both directions, auto reverse works, door opens and closes, I can put in the tape in and take it out, but even when no function is engaged, capstans are rotated by the motor, and it doesn't seam logical.

It doesn't affect the function of the deck or the unit in any way, apart that it unnecessary wears away motor, belt, bearings and makes noise.

I think that it should start running when head and pinch roller are lifted to play position, but I can't seam to tell if it is some switch within mechanism that is stuck, or if it is problem with electronics which controls the unit.

Please help

Thanks in advance!

I SENT YOU PRIVATE MESSAGE GOOD LUCK

 

[SONY FH-150R]

Hi,

I'm up to my ears in fixing and adjusting an Sony FH-150R deck. Yes, yes... I bought one for 45 euros without speakers, got extra deck for spares, but I'm having very ugly times since first day of new year, so I haven't been in the mood to make pics and write about the find. At the moment I'm using the cleaning and fixing of it, as a way to turn my thoughts from things I can't affect.

Here is the problem - Everything works, but as long as the deck is connected together with the rest of the components (power on), the motor rotates the capstans.

All functions work fine, it plays in both directions, auto reverse works, door opens and closes, I can put in the tape in and take it out, but even when no function is engaged, capstans are rotated by the motor, and it doesn't seam logical.

It doesn't affect the function of the deck or the unit in any way, apart that it unnecessary wears away motor, belt, bearings and makes noise.

I think that it should start running when head and pinch roller are lifted to play position, but I can't seam to tell if it is some switch within mechanism that is stuck, or if it is problem with electronics which controls the unit.

Please help

Thanks in advance!

Hi,

To respond to your message:

Yes I can confirm that two capstans cassette player running continuously the mini chain is on.

I have to control the moment after reading your message. and if the mean was silence in the room.

I hope this will help you.

PS: you can find feed belt? everything is original on my cassette player.

Friendly.

 

[LJV]

Thank you! Much appreciated!

 

[baddboybill]

Glad this was all figured out

 

[Superduper]

Looks like it's working normally to me. It appears that the capstan motor is always energized. Seeing as this is a AC only box and not a portable battery operated boombox, Sony probably didn't care. The capstan motor being always on and ready makes for fast logic control action (no delay). The capstan motor only turns the needle and powers the robotic functions anyhow. The actual reel motors are controlled separately. I say leave well enough alone before you mess something up which is possible. The more handling of those bare boards and cables, the more chances of introducing issues where there was none prior.

Indeed, even less - that motor actually does nothing but turning of those two capstans (since it is auto reverse). Everything else is done by second motor and three electromagnets which do the robotic stuff.

Glad this was all figured out

Except........ I'm pretty sure that the capstan motor and flywheel is in fact responsible for the robotic chores such as raising/lowering of the head. The electromagnets merely set the mechanism levers in the proper position so that the necessary action can be accomplished by hitching a ride on the rotating flywheel assembly. The momentum of the flywheel assembly is necessary to provide the initial grunt or torque to overcome the head carriage springs, which are fairly substantial.

 

[jaetee]

FYI: the capstans are always turning in my Nakamichis too...

This is actually quite common in better tape mechanisms.