Sony TC K7 / TC 229 Cassette deck belts - UK Vintage Radio Repair and Restoration Discussion Forum

minerslamp · 16th Mar 2018, 12:26 am

Hi I,m new to this site and not quite sure how to use it But I,ll give it a try.
I have two Sony Cassette recorders ( as title) neither operational as transport drive problems as the rubber belts and idlers have deteriorated ,
I can see the capstan belt is soft and spongy but haven't dismantled enough to check the FF / rewind idlers as that function doesn't work either. ( I don't want to tear them all apart if the parts are not available). Could someone advise me how many rubber tyred idlers there are in these machines ( same transport sytem on both) and a supplier of both ? These are beautifully made machines and I would love to get them working again. Thanks. Mike

paulsherwin · 16th Mar 2018, 12:33 am

I would change the capstan belt before doing anything else. A bad main belt can produce all sorts of strange symptoms. You just need a generic flat belt of the correct size.

minerslamp · 17th Mar 2018, 1:13 pm

Hi, Thanks for the Reply, I have changed the capstan drive belt and play is fine but no transport drives or take up so obviously can't run. Further checking found these models use a separate AC transport drive motor which runs but no drive, so I'm guessing somewhere in the bowels of the mechanism are some sort of rubber idler or drive.

Any info appreciated. If no info forthcoming I'll strip the transport mechanism down to see what's what.

Thanks.

sp10mk11 · 17th Mar 2018, 8:04 pm

My memory is a bit foggy but this transport has an idler wheel from the capstan for the play take up hub.
The rubber used on these machines was very high quality and should still be serviceable even now after all these years
Do keep at these mechs as they were superb units in there day, the heads being ferrite will give no problems
Good luck
Gary

minerslamp · 17th Mar 2018, 9:51 pm

Thanks.

I've found a high quality service manual on hifi engine and looks dead easy to remove the complete tape drive assembly (like you say superbly made) so that's my next move.

Thanks, Mike.

dsergeant · 25th Apr 2018, 2:37 pm

I also have one of these displaying the same symptoms - capstan/play fine but no FF/RW with the transport motor running. I have removed the drive from the unit but it is not clear from the manual (guess I have the same one as you) how to access the idlers etc.

toshiba tony · 25th Apr 2018, 7:40 pm

Excellent decks. These were the tops, I was at Sony when these were sold. I had one till last year but due to downsizing it had to go. Fast forward and rewind is provided by a central idler, Sony (at the time) sold a very special lubricant that aided the idler rack to move between the two spools. At the time they claimed nothing else could be used. I rebelted mine last year, they are readily available.

dsergeant · 1st May 2018, 10:57 am

Thanks. I have stripped it down partially. The reel idler looks fine but appears not to make contact with the reel motor. I wondered whether the relay that pulls it in is not working, but while testing when powered up I seem to have blown something and now none of the control buttons do anything. The service manual I downloaded though does not have a schematic of the control board, only a pcb component view which is pretty unreadable as it is a poor scan. Another copy from a different place was the same so I assume they never published one. So a bit stuck at the moment...

Tractionist · 2nd May 2018, 11:00 pm

My experience with similar Sony cassette decks has been that a full transport strip, clean and re-lube has been necessary in order that swinging idlers and jockeys etc. move smoothly and freely [all that worn rubber has to end up somewhere].

Just work methodically/carefully on a clean bench - and ............ take plenty of reference photographs!

dsergeant · 3rd May 2018, 6:47 am

Yesterday I found out what I had blown up which caused it to be dead - a well hidden fusible resistor on the 40V line. It is now more or less working so indeed it probably was the idler not swinging properly. But the reel counter belt has stretched and needs replacing once I find a suitable one.

A few cunning things with this design - the reel sensor in play is driven via a metal bush attached to the capstan (with a very small set screw). And if you don't fit the reel counter belt it stops since the rotation sensor is part of the counter. Clever!

Dave

Studio263 · 3rd May 2018, 10:08 am

There's a little lever which holds the idler which runs between the capstan shaft and the take up clutch. On the TC-229SD / TC-K7 / TC-K8B this always seizes up, giving the "no take up in playback" symptom you describe. Take it off, clean up the grease, put some fresh stuff on (Castrol LM or similar) and all should be fine.

To do this you will need to remove the capstan flywheel. The pulley on which the idler wheel runs is secured with a tiny allen-headed grub screw, so you will need a very small allen key to remove it. Make sure that you have exactly the right size and that it can't slip as it is very easy to mangle up the socket in the grub screw. Removing it is VERY difficult if you do that.

The reel motor is not used for playback in this model, it is for FF and REW only.

Tractionist · 3rd May 2018, 10:17 am

Good Man - sounds like you're getting there!

Pity it wasn't working last night - I got a superb recording of Randy Crawford live in concert at The Cheltenham Jazz Festival .... on my Sony TC H500!

(There's always BBC IPlayer I suppose .............. !!!!!!!!!!!)

16th Mar 2018, 12:26 am	#1
minerslamp Retired Dormant Member Join Date: Jan 2015 Location: Uxbridge, London, UK. Posts: 5	Sony TC K7 / TC 229 Cassette deck belts Hi I,m new to this site and not quite sure how to use it But I,ll give it a try. I have two Sony Cassette recorders ( as title) neither operational as transport drive problems as the rubber belts and idlers have deteriorated , I can see the capstan belt is soft and spongy but haven't dismantled enough to check the FF / rewind idlers as that function doesn't work either. ( I don't want to tear them all apart if the parts are not available). Could someone advise me how many rubber tyred idlers there are in these machines ( same transport sytem on both) and a supplier of both ? These are beautifully made machines and I would love to get them working again. Thanks. Mike

16th Mar 2018, 12:33 am	#2
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,958	Re: Sony TC K7 / TC 229 Cassette deck belts I would change the capstan belt before doing anything else. A bad main belt can produce all sorts of strange symptoms. You just need a generic flat belt of the correct size.

17th Mar 2018, 1:13 pm	#3
minerslamp Retired Dormant Member Join Date: Jan 2015 Location: Uxbridge, London, UK. Posts: 5	Re: Sony TC K7 / TC 229 Cassette deck belts Hi, Thanks for the Reply, I have changed the capstan drive belt and play is fine but no transport drives or take up so obviously can't run. Further checking found these models use a separate AC transport drive motor which runs but no drive, so I'm guessing somewhere in the bowels of the mechanism are some sort of rubber idler or drive. Any info appreciated. If no info forthcoming I'll strip the transport mechanism down to see what's what. Thanks.

17th Mar 2018, 8:04 pm	#4
sp10mk11 Octode Join Date: Feb 2009 Location: Cornwall, UK. Posts: 1,275	Re: Sony TC K7 / TC 229 Cassette deck belts My memory is a bit foggy but this transport has an idler wheel from the capstan for the play take up hub. The rubber used on these machines was very high quality and should still be serviceable even now after all these years Do keep at these mechs as they were superb units in there day, the heads being ferrite will give no problems Good luck Gary

17th Mar 2018, 9:51 pm	#5
minerslamp Retired Dormant Member Join Date: Jan 2015 Location: Uxbridge, London, UK. Posts: 5	Re: Sony TC K7 / TC 229 Cassette deck belts Thanks. I've found a high quality service manual on hifi engine and looks dead easy to remove the complete tape drive assembly (like you say superbly made) so that's my next move. Thanks, Mike.

25th Apr 2018, 2:37 pm	#6
dsergeant Octode Join Date: Mar 2006 Location: Bracknell, Berkshire,UK. Posts: 1,173	Re: Sony TC K7 / TC 229 Cassette deck belts I also have one of these displaying the same symptoms - capstan/play fine but no FF/RW with the transport motor running. I have removed the drive from the unit but it is not clear from the manual (guess I have the same one as you) how to access the idlers etc.

25th Apr 2018, 7:40 pm	#7
toshiba tony Heptode Join Date: May 2006 Location: Accrington, Lancashire, UK. Posts: 978	Re: Sony TC K7 / TC 229 Cassette deck belts Excellent decks. These were the tops, I was at Sony when these were sold. I had one till last year but due to downsizing it had to go. Fast forward and rewind is provided by a central idler, Sony (at the time) sold a very special lubricant that aided the idler rack to move between the two spools. At the time they claimed nothing else could be used. I rebelted mine last year, they are readily available.

1st May 2018, 10:57 am	#8
dsergeant Octode Join Date: Mar 2006 Location: Bracknell, Berkshire,UK. Posts: 1,173	Re: Sony TC K7 / TC 229 Cassette deck belts Thanks. I have stripped it down partially. The reel idler looks fine but appears not to make contact with the reel motor. I wondered whether the relay that pulls it in is not working, but while testing when powered up I seem to have blown something and now none of the control buttons do anything. The service manual I downloaded though does not have a schematic of the control board, only a pcb component view which is pretty unreadable as it is a poor scan. Another copy from a different place was the same so I assume they never published one. So a bit stuck at the moment...

2nd May 2018, 11:00 pm	#9
Tractionist Heptode Join Date: Apr 2016 Location: Cheltenham, Gloucestershire, UK. Posts: 875	Re: Sony TC K7 / TC 229 Cassette deck belts My experience with similar Sony cassette decks has been that a full transport strip, clean and re-lube has been necessary in order that swinging idlers and jockeys etc. move smoothly and freely [all that worn rubber has to end up somewhere]. Just work methodically/carefully on a clean bench - and ............ take plenty of reference photographs! __________________ Red to red, black to black. Throw the switch and stand well back!

3rd May 2018, 6:47 am	#10
dsergeant Octode Join Date: Mar 2006 Location: Bracknell, Berkshire,UK. Posts: 1,173	Re: Sony TC K7 / TC 229 Cassette deck belts Yesterday I found out what I had blown up which caused it to be dead - a well hidden fusible resistor on the 40V line. It is now more or less working so indeed it probably was the idler not swinging properly. But the reel counter belt has stretched and needs replacing once I find a suitable one. A few cunning things with this design - the reel sensor in play is driven via a metal bush attached to the capstan (with a very small set screw). And if you don't fit the reel counter belt it stops since the rotation sensor is part of the counter. Clever! Dave

3rd May 2018, 10:08 am	#11
Studio263 Octode Join Date: Apr 2007 Location: Hampshire, UK. Posts: 1,577	Re: Sony TC K7 / TC 229 Cassette deck belts There's a little lever which holds the idler which runs between the capstan shaft and the take up clutch. On the TC-229SD / TC-K7 / TC-K8B this always seizes up, giving the "no take up in playback" symptom you describe. Take it off, clean up the grease, put some fresh stuff on (Castrol LM or similar) and all should be fine. To do this you will need to remove the capstan flywheel. The pulley on which the idler wheel runs is secured with a tiny allen-headed grub screw, so you will need a very small allen key to remove it. Make sure that you have exactly the right size and that it can't slip as it is very easy to mangle up the socket in the grub screw. Removing it is VERY difficult if you do that. The reel motor is not used for playback in this model, it is for FF and REW only.

3rd May 2018, 10:17 am	#12
Tractionist Heptode Join Date: Apr 2016 Location: Cheltenham, Gloucestershire, UK. Posts: 875	Re: Sony TC K7 / TC 229 Cassette deck belts Good Man - sounds like you're getting there! Pity it wasn't working last night - I got a superb recording of Randy Crawford live in concert at The Cheltenham Jazz Festival .... on my Sony TC H500! (There's always BBC IPlayer I suppose .............. !!!!!!!!!!!) __________________ Red to red, black to black. Throw the switch and stand well back!