Stella ST461 reel to reel - UK Vintage Radio Repair and Restoration Discussion Forum

Alf Fisher · 17th Oct 2019, 5:23 pm

Hi folks,
I have one of these machines that, like many of that era, has a belt problem where they have gone sticky and cracked or completely broken.

The large square section belt that drives everything is still there and works fine but there should be a small belt that drives the take up reel is simply not there. I don't even know if it was round, square or flat section but I estimate it to be 60mm diameter.

There is a guy on ebay in Italy that allegedly has a set of 4 belts for this machine (Philips EL3552A) but they don't look right. On the machine there are 2 pulleys that are fitted with tyres of about 25mmm diameter that drive the fast forward and rewind hubs.

I have seen it suggested that O rings can be used to replace these belts and tyres so can anyone advise on a source and what sizes please.

Alf
PS Sorry the picture is upside down! I can edit the text but cant change the photo.

AJSmith625 · 18th Oct 2019, 4:47 pm

Hello Alf, for the tyres that drive the edge of the spools on rewind and FF, a suitable replacement can be found from a kit of 'O' rings from the plumbing section at your local Wilkinsons. You will have to buy 2 kits so you can get the same size for each hub, but they are dirt cheap so no problem there. The loose take up belt from my machine which I have just found (lucky I had not thrown it away) is a square section belt measuring 60mm diameter outside edge to outside edge and each edge of the square section is approx 2mm. The one I used which I robbed from a kit of video recorder belts would have been a bit smaller in diameter to allow for the stretch so I would say about 56mm. Have a look at Cricklewood Electronics or one of the other recommended suppliers.

Alan.

Alf Fisher · 18th Oct 2019, 5:55 pm

Hi Alan,
Many thanks for your message which sounds like a perfect solution. I was looking at some cassette recorder belts that seemed like they might work for the takeup drive. The pulley on the motor is a strange shape something like )( and I thought it would be a round section belt but you say its square. There are lots of O rings on ebay.

The original Rewind & FF tyres look like they were square section.
I know someone who says he has a O-ring kit so am waiting to see there's anything suitable in it.

I'll have to clean up the hubs as there is a lots sticky rubber stuck to them. Any idea whats good for cleaning them that wont dissolve the plastic?

Cheers, Alf

AJSmith625 · 18th Oct 2019, 6:40 pm

After reading many posts on here on how to clean off the black goo, I carefully scraped off as much of the soft stuff by holding a small screwdriver against the hubs (don't apply too much pressure so you don't scratch the hubs) and turning them by hand. Then I just used a combination of cotton buds followed by folded up tissues dipped in meths and applied to the hubs in the same way. Its a painstaking job and I did it a bit at a time, but I managed to remove 99% of it. I was reluctant to use anything more potent than meths as others had suggested, in case it dripped on to anything else and caused further problems. Wear some latex gloves as it's a nightmare to get the goo off your skin.

Alan.

AJSmith625 · 18th Oct 2019, 6:51 pm

The original FF / REW tyres were square section, but the round section 'O' rings work a treat.

Alan.

Alf Fisher · 18th Oct 2019, 10:02 pm

Hi Alan, thanks for your detailed report which will definitely help me to fix it.

By the sound of it, you cleaned off the rubbery goo with the wheels still in place.
I removed the circlip on the take-up hub so I could see what was going on under there. It looks like a lot of work to get the RW/FF pulleys off for cleaning.

I had a look through Cricklewood electronics website but couldn't find a 56/60mm one of the right thickness. They have a 54mm one but its only 1.2mm thick. There is a 60.5mm ID x 2.5mm that might be OK. What do you think?

Alf

AJSmith625 · 18th Oct 2019, 11:11 pm

I think that 60.5mm belt will probably be too big, especially as their diameter measurements are inside rim to inside rim and I have been measuring outside to outside. The belt I took off mine was just about turning the takeup spool but slipping very badly. Measuring as Cricklewood do, inside to inside, I would say you would need a diameter of about 52mm. I can see a 52.5mm by 1.6mm on their website but it may be a bit on the thin side and not grip the motor pulley properly. I would do a bit more searching and try and get a 2mm one. Just be aware of how the diameter is measured. As far as cleaning the hubs, I did do them in situ but I did slip off the main belt to avoid this getting contaminated, although I did thoroughly clean this in situ as well afterwards using a piece of tissue dipped in meths. I always try and dismantle as little as possible these days just in case I can't remember how it all goes back together.

Alan

Alf Fisher · 19th Oct 2019, 8:24 am

Hi Alan,
Thanks for the info and details of the cleaning operation. I found a couple of websites in the US that had some belts that were possibles. Its hard to believe there isn't somewhere in UK that has a full and varied selection. Then there is HK & China. They sell 10 off or 20 off but why would I buy those but admittedly, they are cheap. Amazon too but not quite what I'm looking for.
I will continue the quest.

Alf

ben · 21st Oct 2019, 10:56 am

For reference, for the main belt in these use a 175mm O ring.

Note that it must sit on the correct step on the motor pulley (for 50hz mains) or you get slow speed.

Be sure to use a toothpick to get all the goo out the pulleys. Clean also the underside of the spool tables. Check the rubber clutch sections they will likely be goo too.

It pays to be thorough - Otherwise your new belts will soon be sticky and the machine will not work well.

Alf Fisher · 21st Oct 2019, 2:23 pm

Hi Ben,
Thanks for your reply. For some reason, the main belt is fine.
Its the take-up reel belt that has vanished and the rewind and FF tyres have turned to goo. I have to clean the hubs as they have picked up a lot of rubber goo from the tyres.
I'm fine with cleaning out all the goo-ey rubber.
I recently had to do it on my Teletype KSR33 before fitting a new typehead rubber hammer pad. It this pad isn't changed and the machine is being used, the hammer will quickly destroy the typehead and they don't come cheap!
Regards,
Alf

Alf Fisher · 31st Oct 2019, 5:48 pm

By way of an update, I have now fitted new O-rings for the FF and Rewind pulleys and they work fine.
The next problem is the brakes - the rubber parts are cracked and falling to bits.
Is there a suitable way of effecting a repair or fitting something to replace the brake rubbers.

Alf

ben · 31st Oct 2019, 10:55 pm

I usually use bits of rubber CRT wedges.

Alf Fisher · 1st Nov 2019, 12:51 am

Hi Ben,
Sorry but I don't know what CRT wedges are.
Please can you explain.

Alf

ben · 1st Nov 2019, 9:58 am

TV tube scan coil wedges .

Alf Fisher · 1st Nov 2019, 11:14 am

Ben,
OK Thank you - you learn something everyday!

Cheers.

Alf Fisher · 21st Nov 2019, 5:38 pm

Well I'm getting there with this machine but today I was replacing the valves and while juggling with the deck, the brown wire from the motor broke off a tag on the transformer and I cant be sure which one it was. The circuit diagram isn't much help as there isn't a physical picture of the tag layout on the transformer. Can anyone help please?

Alf

17th Oct 2019, 5:23 pm	#1
Alf Fisher Hexode Join Date: Sep 2005 Location: Potton, Bedfordshire, UK. Posts: 293	Stella ST461 reel to reel Hi folks, I have one of these machines that, like many of that era, has a belt problem where they have gone sticky and cracked or completely broken. The large square section belt that drives everything is still there and works fine but there should be a small belt that drives the take up reel is simply not there. I don't even know if it was round, square or flat section but I estimate it to be 60mm diameter. There is a guy on ebay in Italy that allegedly has a set of 4 belts for this machine (Philips EL3552A) but they don't look right. On the machine there are 2 pulleys that are fitted with tyres of about 25mmm diameter that drive the fast forward and rewind hubs. I have seen it suggested that O rings can be used to replace these belts and tyres so can anyone advise on a source and what sizes please. Alf PS Sorry the picture is upside down! I can edit the text but cant change the photo. Attached Thumbnails Last edited by AC/HL; 17th Oct 2019 at 6:20 pm. Reason: Image rotated

18th Oct 2019, 4:47 pm	#2
AJSmith625 Pentode Join Date: Nov 2017 Location: Birmingham, West Midlands, UK. Posts: 171	Re: Stella ST461 reel to reel Hello Alf, for the tyres that drive the edge of the spools on rewind and FF, a suitable replacement can be found from a kit of 'O' rings from the plumbing section at your local Wilkinsons. You will have to buy 2 kits so you can get the same size for each hub, but they are dirt cheap so no problem there. The loose take up belt from my machine which I have just found (lucky I had not thrown it away) is a square section belt measuring 60mm diameter outside edge to outside edge and each edge of the square section is approx 2mm. The one I used which I robbed from a kit of video recorder belts would have been a bit smaller in diameter to allow for the stretch so I would say about 56mm. Have a look at Cricklewood Electronics or one of the other recommended suppliers. Alan.

18th Oct 2019, 5:55 pm	#3
Alf Fisher Hexode Join Date: Sep 2005 Location: Potton, Bedfordshire, UK. Posts: 293	Re: Stella ST461 reel to reel Hi Alan, Many thanks for your message which sounds like a perfect solution. I was looking at some cassette recorder belts that seemed like they might work for the takeup drive. The pulley on the motor is a strange shape something like )( and I thought it would be a round section belt but you say its square. There are lots of O rings on ebay. The original Rewind & FF tyres look like they were square section. I know someone who says he has a O-ring kit so am waiting to see there's anything suitable in it. I'll have to clean up the hubs as there is a lots sticky rubber stuck to them. Any idea whats good for cleaning them that wont dissolve the plastic? Cheers, Alf

18th Oct 2019, 6:40 pm	#4
AJSmith625 Pentode Join Date: Nov 2017 Location: Birmingham, West Midlands, UK. Posts: 171	Re: Stella ST461 reel to reel After reading many posts on here on how to clean off the black goo, I carefully scraped off as much of the soft stuff by holding a small screwdriver against the hubs (don't apply too much pressure so you don't scratch the hubs) and turning them by hand. Then I just used a combination of cotton buds followed by folded up tissues dipped in meths and applied to the hubs in the same way. Its a painstaking job and I did it a bit at a time, but I managed to remove 99% of it. I was reluctant to use anything more potent than meths as others had suggested, in case it dripped on to anything else and caused further problems. Wear some latex gloves as it's a nightmare to get the goo off your skin. Alan. Last edited by AJSmith625; 18th Oct 2019 at 6:42 pm. Reason: spelling correction

18th Oct 2019, 6:51 pm	#5
AJSmith625 Pentode Join Date: Nov 2017 Location: Birmingham, West Midlands, UK. Posts: 171	Re: Stella ST461 reel to reel The original FF / REW tyres were square section, but the round section 'O' rings work a treat. Alan.

18th Oct 2019, 10:02 pm	#6
Alf Fisher Hexode Join Date: Sep 2005 Location: Potton, Bedfordshire, UK. Posts: 293	Re: Stella ST461 reel to reel Hi Alan, thanks for your detailed report which will definitely help me to fix it. By the sound of it, you cleaned off the rubbery goo with the wheels still in place. I removed the circlip on the take-up hub so I could see what was going on under there. It looks like a lot of work to get the RW/FF pulleys off for cleaning. I had a look through Cricklewood electronics website but couldn't find a 56/60mm one of the right thickness. They have a 54mm one but its only 1.2mm thick. There is a 60.5mm ID x 2.5mm that might be OK. What do you think? Alf

18th Oct 2019, 11:11 pm	#7
AJSmith625 Pentode Join Date: Nov 2017 Location: Birmingham, West Midlands, UK. Posts: 171	Re: Stella ST461 reel to reel I think that 60.5mm belt will probably be too big, especially as their diameter measurements are inside rim to inside rim and I have been measuring outside to outside. The belt I took off mine was just about turning the takeup spool but slipping very badly. Measuring as Cricklewood do, inside to inside, I would say you would need a diameter of about 52mm. I can see a 52.5mm by 1.6mm on their website but it may be a bit on the thin side and not grip the motor pulley properly. I would do a bit more searching and try and get a 2mm one. Just be aware of how the diameter is measured. As far as cleaning the hubs, I did do them in situ but I did slip off the main belt to avoid this getting contaminated, although I did thoroughly clean this in situ as well afterwards using a piece of tissue dipped in meths. I always try and dismantle as little as possible these days just in case I can't remember how it all goes back together. Alan

19th Oct 2019, 8:24 am	#8
Alf Fisher Hexode Join Date: Sep 2005 Location: Potton, Bedfordshire, UK. Posts: 293	Re: Stella ST461 reel to reel Hi Alan, Thanks for the info and details of the cleaning operation. I found a couple of websites in the US that had some belts that were possibles. Its hard to believe there isn't somewhere in UK that has a full and varied selection. Then there is HK & China. They sell 10 off or 20 off but why would I buy those but admittedly, they are cheap. Amazon too but not quite what I'm looking for. I will continue the quest. Alf

21st Oct 2019, 10:56 am	#9
ben Dekatron Join Date: Aug 2006 Location: Madrid, Spain / Wirral, UK Posts: 7,498	Re: Stella ST461 reel to reel For reference, for the main belt in these use a 175mm O ring. Note that it must sit on the correct step on the motor pulley (for 50hz mains) or you get slow speed. Be sure to use a toothpick to get all the goo out the pulleys. Clean also the underside of the spool tables. Check the rubber clutch sections they will likely be goo too. It pays to be thorough - Otherwise your new belts will soon be sticky and the machine will not work well. __________________ Regards, Ben.

21st Oct 2019, 2:23 pm	#10
Alf Fisher Hexode Join Date: Sep 2005 Location: Potton, Bedfordshire, UK. Posts: 293	Re: Stella ST461 reel to reel Hi Ben, Thanks for your reply. For some reason, the main belt is fine. Its the take-up reel belt that has vanished and the rewind and FF tyres have turned to goo. I have to clean the hubs as they have picked up a lot of rubber goo from the tyres. I'm fine with cleaning out all the goo-ey rubber. I recently had to do it on my Teletype KSR33 before fitting a new typehead rubber hammer pad. It this pad isn't changed and the machine is being used, the hammer will quickly destroy the typehead and they don't come cheap! Regards, Alf

31st Oct 2019, 5:48 pm	#11
Alf Fisher Hexode Join Date: Sep 2005 Location: Potton, Bedfordshire, UK. Posts: 293	Re: Stella ST461 reel to reel By way of an update, I have now fitted new O-rings for the FF and Rewind pulleys and they work fine. The next problem is the brakes - the rubber parts are cracked and falling to bits. Is there a suitable way of effecting a repair or fitting something to replace the brake rubbers. Alf

31st Oct 2019, 10:55 pm	#12
ben Dekatron Join Date: Aug 2006 Location: Madrid, Spain / Wirral, UK Posts: 7,498	Re: Stella ST461 reel to reel I usually use bits of rubber CRT wedges. __________________ Regards, Ben.

1st Nov 2019, 12:51 am	#13
Alf Fisher Hexode Join Date: Sep 2005 Location: Potton, Bedfordshire, UK. Posts: 293	Re: Stella ST461 reel to reel Hi Ben, Sorry but I don't know what CRT wedges are. Please can you explain. Alf

1st Nov 2019, 9:58 am	#14
ben Dekatron Join Date: Aug 2006 Location: Madrid, Spain / Wirral, UK Posts: 7,498	Re: Stella ST461 reel to reel TV tube scan coil wedges . __________________ Regards, Ben.

1st Nov 2019, 11:14 am	#15
Alf Fisher Hexode Join Date: Sep 2005 Location: Potton, Bedfordshire, UK. Posts: 293	Re: Stella ST461 reel to reel Ben, OK Thank you - you learn something everyday! Cheers.

21st Nov 2019, 5:38 pm	#16
Alf Fisher Hexode Join Date: Sep 2005 Location: Potton, Bedfordshire, UK. Posts: 293	Re: Stella ST461 reel to reel Well I'm getting there with this machine but today I was replacing the valves and while juggling with the deck, the brown wire from the motor broke off a tag on the transformer and I cant be sure which one it was. The circuit diagram isn't much help as there isn't a physical picture of the tag layout on the transformer. Can anyone help please? Alf