Sony TC-K444 ES II Service data - UK Vintage Radio Repair and Restoration Discussion Forum

vampyretim · 16th Nov 2016, 12:38 pm

Hi all,

I'm trying to repair the above cassette deck which is not playing tapes and seems to trip a relay when you try to.

It's a very complicated cassette deck and I'm not going to get anywhere without service data.

Many thanks,
Tim.

TIMTAPE · 16th Nov 2016, 2:54 pm

I seem to recall that model has a counter to the right side of the deck mechanism. It probably incorporates an "End of Tape" shutoff sensor. If so I'd check the rubber belt is driving the small pulley when there is tape drive. If it isn't that is probably the problem.

Tim

tri-comp · 17th Nov 2016, 12:21 am

Hi Tim's !

I'm not too sure about this but as far as I remember there were some problems with the auto-stop circuit in these models.
The series actually consists of 3 variants; the TC-K444ES-II, the TC-K555ES and the TC-K666ES all built fairly much alike.
I seem to remember that the auto-stop and speed-control for FF/REW was done with the help of a couple of photo-transistors under the reel-tables.
The underside of the tables were mounted with som silvery reflective plastic-foil in a pattern.
When the transistors gets dirty on the surfaces and/or the reflective foil gets covered in grime the auto-stop will kick-in as it's short of pulses indicating tape-travel.
To fix this just remove the tables and give everything a good cleaning with IPA.

Hope I'm right.

sp10mk11 · 17th Nov 2016, 12:44 am

I remember some Sony models that relied on a bulb to energise optical sensors on the right hand spool, if the bulb went then the auto stop would come on rapidly.
Gary

TIMTAPE · 17th Nov 2016, 4:00 am

I checked a ES model I have here. No, no belt. The counter is electronic. So yes there must be sensors of some kind under the reel tables as Tri Comp mentions.. Sorry for the lapse in memory.

Tim

vampyretim · 23rd Nov 2016, 11:28 am

Hi guys,

Thanks for all your help. I'm having a bit of difficulty finding the parts you describe.

I've uploaded a picture would you mind having a look?

Many thanks,
Tim.

TIMTAPE · 23rd Nov 2016, 1:56 pm

You dont say if the tape reels are turning. Look at the cassette just as you press play. Do the tape reels turn at all, even for a short time?

Looking at the back of the tape drive mechanism, does the rubber belt turn the flywheel when the machine is switched on or when you have a cassette in and press play?

Do tapes fast forward or rewind? Even for a short time?

kevinaston1 · 23rd Nov 2016, 1:56 pm

A quick look around the web does not bring any reuslts for a TC-K444 service manual, but Electrotanya have the TC-K555 service manual; it may be similar enough to help you.

Regards.

kevin

vampyretim · 23rd Nov 2016, 3:54 pm

Quote:

Originally Posted by TIMTAPE

You dont say if the tape reels are turning. Look at the cassette just as you press play. Do the tape reels turn at all, even for a short time?

Hi Tim,

The take up reel does move for a moment.

Looking at the cassette player from the front I took off the plastic plate that sits behind the cassette tape and I can see the bulb. I can see the sensors behind the plastic reel tables.

When I shine an external lamp on the sensors the deck plays as it should.

The internal bulb does work though.

I want to get behind the reel tables to clean the sensors but can't work out how to do it.

Any idea?

Thanks again,
Tim.

TIMTAPE · 24th Nov 2016, 5:51 am

Sorry, no. I've not had a problem with mine in that regard and so have never needed to dismantle. But good what you've found. Does sound like sensors not receiving the light signal enough.

Tim

vampyretim · 24th Nov 2016, 6:05 pm

Hello Tim,

I've managed to get to the photo transistors, I've cleaned them but I still have the fault.

It must be the lamp. Can they emit light still if they're on the way out?

The tape player does work with an external lamp but it won't rewind for very long without tripping the relay even with the help of an external lamp. It will fast forward with the help of the external lamp.

It plays fine with the external lamp.

Thanks for taking the time to help me.

16th Nov 2016, 12:38 pm	#1
vampyretim Heptode Join Date: Aug 2011 Location: Bristol, UK. Posts: 538	Sony TC-K444 ES II Service data Hi all, I'm trying to repair the above cassette deck which is not playing tapes and seems to trip a relay when you try to. It's a very complicated cassette deck and I'm not going to get anywhere without service data. Many thanks, Tim.

16th Nov 2016, 2:54 pm	#2
TIMTAPE Octode Join Date: Jul 2006 Location: Perth, Western Australia Posts: 1,971	Re: Sony TC-K444 ES II Service data I seem to recall that model has a counter to the right side of the deck mechanism. It probably incorporates an "End of Tape" shutoff sensor. If so I'd check the rubber belt is driving the small pulley when there is tape drive. If it isn't that is probably the problem. Tim

17th Nov 2016, 12:21 am	#3
tri-comp Heptode Join Date: Oct 2008 Location: Aalborg, Denmark Posts: 903	Re: Sony TC-K444 ES II Service data Hi Tim's ! I'm not too sure about this but as far as I remember there were some problems with the auto-stop circuit in these models. The series actually consists of 3 variants; the TC-K444ES-II, the TC-K555ES and the TC-K666ES all built fairly much alike. I seem to remember that the auto-stop and speed-control for FF/REW was done with the help of a couple of photo-transistors under the reel-tables. The underside of the tables were mounted with som silvery reflective plastic-foil in a pattern. When the transistors gets dirty on the surfaces and/or the reflective foil gets covered in grime the auto-stop will kick-in as it's short of pulses indicating tape-travel. To fix this just remove the tables and give everything a good cleaning with IPA. Hope I'm right.

17th Nov 2016, 12:44 am	#4
sp10mk11 Octode Join Date: Feb 2009 Location: Cornwall, UK. Posts: 1,275	Re: Sony TC-K444 ES II Service data I remember some Sony models that relied on a bulb to energise optical sensors on the right hand spool, if the bulb went then the auto stop would come on rapidly. Gary

17th Nov 2016, 4:00 am	#5
TIMTAPE Octode Join Date: Jul 2006 Location: Perth, Western Australia Posts: 1,971	Re: Sony TC-K444 ES II Service data I checked a ES model I have here. No, no belt. The counter is electronic. So yes there must be sensors of some kind under the reel tables as Tri Comp mentions.. Sorry for the lapse in memory. Tim

23rd Nov 2016, 11:28 am	#6
vampyretim Heptode Join Date: Aug 2011 Location: Bristol, UK. Posts: 538	Re: Sony TC-K444 ES II Service data Hi guys, Thanks for all your help. I'm having a bit of difficulty finding the parts you describe. I've uploaded a picture would you mind having a look? Many thanks, Tim. Attached Thumbnails

23rd Nov 2016, 1:56 pm	#7
TIMTAPE Octode Join Date: Jul 2006 Location: Perth, Western Australia Posts: 1,971	Re: Sony TC-K444 ES II Service data You dont say if the tape reels are turning. Look at the cassette just as you press play. Do the tape reels turn at all, even for a short time? Looking at the back of the tape drive mechanism, does the rubber belt turn the flywheel when the machine is switched on or when you have a cassette in and press play? Do tapes fast forward or rewind? Even for a short time?

23rd Nov 2016, 1:56 pm	#8
kevinaston1 Hexode Join Date: Aug 2014 Location: Featherstone, West Yorkshire, UK. Posts: 386	Re: Sony TC-K444 ES II Service data A quick look around the web does not bring any reuslts for a TC-K444 service manual, but Electrotanya have the TC-K555 service manual; it may be similar enough to help you. Regards. kevin

24th Nov 2016, 5:51 am	#10
TIMTAPE Octode Join Date: Jul 2006 Location: Perth, Western Australia Posts: 1,971	Re: Sony TC-K444 ES II Service data Sorry, no. I've not had a problem with mine in that regard and so have never needed to dismantle. But good what you've found. Does sound like sensors not receiving the light signal enough. Tim

24th Nov 2016, 6:05 pm	#11
vampyretim Heptode Join Date: Aug 2011 Location: Bristol, UK. Posts: 538	Re: Sony TC-K444 ES II Service data Hello Tim, I've managed to get to the photo transistors, I've cleaned them but I still have the fault. It must be the lamp. Can they emit light still if they're on the way out? The tape player does work with an external lamp but it won't rewind for very long without tripping the relay even with the help of an external lamp. It will fast forward with the help of the external lamp. It plays fine with the external lamp. Thanks for taking the time to help me.