Replacing drive belt on Stellaphone ST454
 

Hi.

I've been given a stack of tapes so bought a Stella phone ST454. However, after a few hours the reels stopped turning. I took the top off and the main drive belt has snapped. It's a square type so I superglued it as a temporary fix but can't set how on earth I can get to the main wheel. I downloaded the service data for that model but no mention of what screws to remove. Would I need to find the actual manual for this?

I've attached a pic.

Re: Replacing drive belt on Stellaphone ST454
 

It's the Stella variant of the Philips EL3541 if that's any help.

https://www.radiomuseum.org/r/philips_el354100h.html

Hifi Engine have some service data. You will need to register to download it, but that is quick and free.

https://www.hifiengine.com/manual_li...s/el3541.shtml

Re: Replacing drive belt on Stellaphone ST454
 

This is from memory, but I think this is the way it goes (red line in the image below). As far as I remember you don't need to remove any screws at all, although you have to fiddle with the brake arms in order to squeeze the belt through. Also have to remove the counter belt temporarily.

Re: Replacing drive belt on Stellaphone ST454
 

Oh that would be great if it goes that way. I was thinking it went round the flywheel (if thats what its called?) Sorry I'm a complete novice! (and female :-) )

Re: Replacing drive belt on Stellaphone ST454
 

Ah okay I've figured it out, its now in place and everything is moving as it should, the only trouble I'm having really is making sure the belt isn't twisted.

Re: Replacing drive belt on Stellaphone ST454
 

Well thank you very much Ricard! My great grandfather was obsessed with his machine and was always recording people. There are so many family members on these tapes talking and singing, who are longer here so its amazing to hear their voices :)

Thanks again, Justine

Re: Replacing drive belt on Stellaphone ST454
 

Great that you got it going again!

The belt path in that machine is not intuitive, and without other evidence my first thought would also have been for the belt to go around the front of the flywheel and not the back.

If the belt is twisted somewhere it doesn't really make that much of a difference in practice, although it looks nicer and brings a bit of piece of mind to have it run true.

(And no need to apologize for being a novice nor a female ... :) )

Re: Replacing drive belt on Stellaphone ST454
 

If you haven’t ordered your replacement belt yet I would recommend contacting Dave Hughes whose details are in this thread:

https://www.vintage-radio.net/forum/...d.php?p=907961

When I restored my first Philips EL3541 (which has been in my family since new) he provided a very useful kit of parts and instruction manual all for a fairly modest price.

If the Stella is anything like the Philips there will be some friction material under the reel tables that turns to goo. Dave’s kit contains replacements for this and hints on how to clean up the old mess.

Re: Replacing drive belt on Stellaphone ST454
 

Its very grimy inside so will order a kit thanks!

Re: Replacing drive belt on Stellaphone ST454
 

It doesnt affect this machine, it's the later machines that would have been affected, if the original belt is there but broken, then the rest of the machine will be OK.

Re: Replacing drive belt on Stellaphone ST454
 

The friction studs underneath the reel holders do decompose with time, usually they mostly crumble, but they can get a bit gooey too (not at all to the same degree as the rubber that Philips used later though), and probably need replacing if nothing else to get fast wind to work properly.

Re: Replacing drive belt on Stellaphone ST454
 

I've given up supergluing the belt it only lasts for about an hour so getting a new one. Doesn't seem to be any goo as far as I can see just general grime. And the rubber bits seem okay not hard at all

Re: Replacing drive belt on Stellaphone ST454
 

Hello
I'm trying to help my elderly neighbour with his Stellaphone ST454 - the belt had snapped. As a temporary fix he has glued the belt together and I have emailed Mr D Hughes with a view to obtaining a new belt.

We have now re fitted the belt, however the reels no longer turn at normal play/record speed or at fast forward or fast reverse. It does look as though the "friction pads" are missing ? or at least, 2 out of 3 are missing on both reels (coupling wheels). Am I right in saying that there should be 3 fiction pads on each reel? The Stellaphone was playing OK prior to the belt snapping, the primary drive belt does appear to correctly fitted.

Does anyone have a picture of the fiction pads as fitted to the reels (coupling wheels)? Can someone kindly confirm that without the friction pads are vital for normal play and record? I have downloaded the PDF for the Philips version. Many thanks Matt

Re: Replacing drive belt on Stellaphone ST454
 

The friction pads are only needed for fast winding. For ordinary play and record, the smaller plastic disks under each reel table provide the clutch (take up) / brake (supply) function.

Here are a couple of pictures of what the pads should look like. There are indeed three per reel table, mounted in the quite obvious holes in the bottom part intended for that purpose.

Sometimes it's easy to get the belt not to ride in the groove in the bottom pulley under the reel holders which usually leads to the motor not running at all though, if the belt gets wedged somewhere.

Re: Replacing drive belt on Stellaphone ST454
 

This is not really a very good picture of the belt path, but if you look carefully you can see where it runs in the grooves of the pulleys beneath the reel tables. Also see the pictures higher up in this thread (which you've probably done of course).

Re: Replacing drive belt on Stellaphone ST454
 

Many thanks for the replies, the main belt looks to be fitted correctly. The coupling wheels both turn in unison, sorry I should have stated this in my first post. The small plastic discs look OK (parts 126 and 93) - (the right hand one has the spigot and the spindles are fully seated). Do part no's 135 and 136 (look like small washers) play a vital part in providing play/record ? With regard to the the friction pads, are they fitted dome side up into the coupling wheels ? should the small plastic discs be cleaned in meths or alcohol ?

Matt

Re: Replacing drive belt on Stellaphone ST454
 

One thing struck me: if while lifting the reel tables you have inadvertantly lifted (and turned) the shafts that the reel tables ride on (part 90), note that the bottom of the shafts are not circular but have a flat so as to ride in the groove in the lifting mechanism (parts 87 and 88). One needs to turn the shafts until they fall into the groove.

Another issue can be that the grease in the hole that the shafts run through gets hard with age causing them to bind, so that the reel table doesn't fall down with gravity as it should. Since the machine worked beforehand I wouldn't think this is the problem however.

The small washers you mention are used as shims to get the reel tables at the right height in play/record mode. The number of washers used is adjusted on an individual basis in production to match the tolerance of the actual pieces used in a specific machine. The number of washers is not critical for operation, but if the reel table height is wrong the tape will rub against one of the flanges when playing.

Yes, the friction pads should be dome side up. I believe it's now possible to get replacements from the similar places that sell belts. Failing that, a piece of (homogenous) cork can be cut to shape and used instead, with good results. Others have reported using hard rubber, like the type used for door stops, cut to shape.

When cleaning the plastic parts, meths or pure alcohol, or isopropanol should all be suitable. Normally cleaning of these parts is not needed though, as the clutches only are used in play/record mode. (There are other recorders where the same clutch is used also for fast wind, with springs used to increase the friction, and they can be rather more sensitive to slippage).

By the way, for completeness, and because I just found some measurements I'd made of the friction pad in the pictures above: The diameter is 8.1 mm, and the height from the bottom to the top of the domed surface on top is 6.4 mm, with the height along the side of the friction pad being 5 mm. (I've also noted a part number 46240009 but that's certainly moot at this point as any old stock found will have degraded just as the originals by this time).