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Vintage Tape (Audio), Cassette, Wire and Magnetic Disc Recorders and Players Open-reel tape recorders, cassette recorders, 8-track players etc.

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Old 12th Jun 2021, 4:00 pm   #21
Chris-Something
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Default Re: Sony TC-560 | Slow Fast-Forward & Rewind

OK, cool, so that works fine. Thanks for walking me through that, I learned something new today.
I still think there's some kind of electronic issue in play because of how consistent it is no matter what I do, but if the problem is lubrication, where would suggest as key locations to check?
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Old 12th Jun 2021, 4:10 pm   #22
ms660
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Default Re: Sony TC-560 | Slow Fast-Forward & Rewind

What are the symptoms in Play? I thought it was just REW and FF that has a problem?

Lawrence.
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Old 12th Jun 2021, 4:15 pm   #23
Chris-Something
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Default Re: Sony TC-560 | Slow Fast-Forward & Rewind

Play functions are alright, but they do take one or two seconds to get up to speed in both directions. Maybe the torque issue is there as well...
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Old 12th Jun 2021, 4:45 pm   #24
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Default Re: Sony TC-560 | Slow Fast-Forward & Rewind

Actually, I just remembered that I tested both of my motors in the deck without a belt on, just spinning freely and they showed all the same symptoms; slow to accelerate and not a good top speed in FF/RWD.
That leads me to think that lubrication isn't an issue (wouldn't hurt to do it though), but an electronics issue, unless I somehow coincidentally got two motors with the exact same problem, which I doubt.
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Old 12th Jun 2021, 5:14 pm   #25
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Default Re: Sony TC-560 | Slow Fast-Forward & Rewind

You could check the supply voltages to the motor circuit(s), I can't talk you through that just now as I'm in middle of doing the evening meal...(panic) but I will do later if no one else does, if the problem doesn't appear to be there then it's good practice anyway for learning to find your way around a circuit board and taking measurements.

Lawrence.
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Old 12th Jun 2021, 5:25 pm   #26
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Default Re: Sony TC-560 | Slow Fast-Forward & Rewind

It's all good if you can't easily respond right now, as I'm about to go to sleep anyway, haha (it's 3:25am here as I type this).
My only worry about the servo amp board (if that's the motor circuit you're referring to) is that in FF/RWD modes that board is by-passed. It's also the second servo amp board this deck has had. My first and second motors both behave exactly the same with both servo amp boards, even after recapping them.

Well, until I hear from you or anyone else here again, good night.
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Old 12th Jun 2021, 5:55 pm   #27
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Default Re: Sony TC-560 | Slow Fast-Forward & Rewind

To check out the supply voltages first check the voltage between the two points on the power amplifier circuit board on page 26 of the service manual where the Blue and Red wires connect to on the left hand side of the board up near the top, make a note of the voltage (DC) when in Play mode and then when in REW/FF mode.

Next measure the voltage between the two points on the servo amplifier circuit board (page 29 of the manual) that the Yellow and Blue wires are connected to on the top edge of the board at the far right, make a note of the voltage (DC) when in Play mode and then when in REW/FF mode.

Hopefully that should tell us if there's anything significantly wrong with the motor supply voltages to the servo board in both Play and REW/FF.

Lawrence.
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Old 12th Jun 2021, 10:13 pm   #28
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Default Re: Sony TC-560 | Slow Fast-Forward & Rewind

I think it might be wise to fully exhaust the possibility that this is fault is mechanical in origin.

- Remove spool tables and lubricate bearings with light oil. Ditto motor bearing if you haven't already.
- Check pulley is firm on motor shaft - been caught by that before!
- Check state of guide posts in tape path. If these have seen lots of hours and are worn flat, or to the base metal, you'd be amazed at the drag this can put on the tape path. Fortunately many can be loosened and rotated 90 to expose new surface.
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Old 13th Jun 2021, 2:09 am   #29
Chris-Something
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Default Re: Sony TC-560 | Slow Fast-Forward & Rewind

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Originally Posted by ms660 View Post
To check out the supply voltages first check the voltage between the two points on the power amplifier circuit board on page 26 of the service manual where the Blue and Red wires connect to on the left hand side of the board up near the top, make a note of the voltage (DC) when in Play mode and then when in REW/FF mode.

Next measure the voltage between the two points on the servo amplifier circuit board (page 29 of the manual) that the Yellow and Blue wires are connected to on the top edge of the board at the far right, make a note of the voltage (DC) when in Play mode and then when in REW/FF mode.

Hopefully that should tell us if there's anything significantly wrong with the motor supply voltages to the servo board in both Play and REW/FF.

Lawrence.
I've measured all mentioned locations in all modes and these are the results:

Power Amplifier Circuit
- Forward Play Mode - 15.08v
- Reverse Play Mode - 15.34v
- Fast-Forward - 15.86v
- Rewind - 15.71

Servo Amplifier Circuit
- Forward Play Mode - 15.13v
- Reverse Play Mode - 15.36v
- Fast-Forward - 15.63v
- Rewind - 15.67v
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Old 13th Jun 2021, 2:20 am   #30
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Default Re: Sony TC-560 | Slow Fast-Forward & Rewind

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Originally Posted by ben View Post
I think it might be wise to fully exhaust the possibility that this is fault is mechanical in origin.

- Remove spool tables and lubricate bearings with light oil. Ditto motor bearing if you haven't already.
- Check pulley is firm on motor shaft - been caught by that before!
- Check state of guide posts in tape path. If these have seen lots of hours and are worn flat, or to the base metal, you'd be amazed at the drag this can put on the tape path. Fortunately many can be loosened and rotated 90 to expose new surface.
These are good suggestions, but the same symptoms show with the spool tables off. I've also looked at the motor and all seems physically well and identical to my other motor which behaves the same way. The pulley is definitely firm, the belts are nice and the guide posts are nice and round.
I don't doubt the possibility of a possible mechanical fault dragging it down, but considering the motor is slow to accelerate when the drive belt isn't even attached (i.e. spinning freely), I think it's more likely to be electrical.
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Old 13th Jun 2021, 6:40 am   #31
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Default Re: Sony TC-560 | Slow Fast-Forward & Rewind

I'd re-check the idler at this point - if the surface is shiny a good scrub with IPA should get you down to a softer matt surface, which will have greater grip. I had to deal with a slow-running TC377 where the cause was just this.

It's also well to remember that this is a sixties design intended to be capable of running off batteries - the available motor torque may have been limited for this reason by design, making the drive conditions critical for satisfactory operation.

Last edited by Ted Kendall; 13th Jun 2021 at 6:47 am.
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Old 13th Jun 2021, 7:23 am   #32
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Default Re: Sony TC-560 | Slow Fast-Forward & Rewind

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Originally Posted by Ted Kendall View Post
I'd re-check the idler at this point - if the surface is shiny a good scrub with IPA should get you down to a softer matt surface, which will have greater grip. I had to deal with a slow-running TC377 where the cause was just this.

It's also well to remember that this is a sixties design intended to be capable of running off batteries - the available motor torque may have been limited for this reason by design, making the drive conditions critical for satisfactory operation.
My deck doesn't have an idler wheel. Everything that rotates is rotated by belts.
There's a chance that the torque limit is true, but I've found a video of the same deck and in FF/RWD it runs much quicker than mine.

I've seen so many videos of reel-to-reel repairs and they've all got idlers. Why did mine have to be different? Haha.
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Old 13th Jun 2021, 8:09 am   #33
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Default Re: Sony TC-560 | Slow Fast-Forward & Rewind

If the belts lack a certain amount of elasticity they may well be the cause. Did you replace them?
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Old 13th Jun 2021, 8:14 am   #34
Chris-Something
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Default Re: Sony TC-560 | Slow Fast-Forward & Rewind

Yes, every belt (apart from the time counter belt) has been replaced. Though that improved different problems, like slipping, it didn't fix the speed issue.
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Old 13th Jun 2021, 12:18 pm   #35
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Default Re: Sony TC-560 | Slow Fast-Forward & Rewind

Thorough cleaning of the pulleys is essential when changing belts to ensure correct traction - belt deposits are not always obvious and, even when visible, can be so even as to look like an intended strip of paint. Cocktail sticks, cotton buds and IPA are the tools of choice.
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Old 13th Jun 2021, 12:35 pm   #36
Chris-Something
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Default Re: Sony TC-560 | Slow Fast-Forward & Rewind

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Originally Posted by Ted Kendall View Post
Thorough cleaning of the pulleys is essential when changing belts to ensure correct traction - belt deposits are not always obvious and, even when visible, can be so even as to look like an intended strip of paint. Cocktail sticks, cotton buds and IPA are the tools of choice.
Whenever I replace the belts I make sure to do exactly that. Removing pulleys to clean them with IPA until no more residue comes up on the cotton buds and also making sure the belts are clean before putting them on.

I know what you mean by what would like like an intended strip of paint, haha. Fixing old floppy drives and CED machines has exposed me to that, big time.
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