Philips EL3541 reel to reel not rewinding

[Timvintage]

Hi everyone,
I haven't been on here in a few months; been having computer problems and have been pretty busy too! However I haven't lost interest in vintage audio!
I currently have been trying to repair a Philips El3541. I read quite a few threads about it on here, and got lots of valuable info!
When I got the machine, it would play, but not rewind and fast-forward. From my research I found that I needed to replace the friction pads under the spool holders. I am actually completely blind, but do a lot of mechanical repairs myself, and I have someone sighted who can help me out a little with some visual stuff.
I took the advice of one of the members who said you can buy 8 mm cork balls, then file them down so that they protrude about 1 mm above the circular metal things they sit in.
I think I have done this right; they all appear to be at the same hight, and there has been some improvement! It will now play and fast-forward, but rewind still doesn't work.
If you take the tape off the machine, both reels are turning, meaning that when there is a tape threaded, each reel is trying to pull the tape in opposite directions, resulting in no movement.
Can anyone help me out with anything else I should look out for? Is there any other things that could be causing this, or should I just sand the cork down a bit more? I am worried that if I sand them more, they will be too low and then I will have to start all over again!
The drive belt still seams tight and in good condition, so I haven't replaced that. The counter belt was perished so I have replaced that.

Thank you all so much,
Tim

[Voxophone]

Hi Tim,

It sounds to me like the cork pads on the take-up clutch (the right hand reel from the front) may be protruding too much and making contact during rewind when they should not be. I'm not familiar with your model per say, but on my old Philips machine the reel tables drop down onto the cork pads depending on which mode is engaged. For example, on rewind, the left hand reel should drop onto its pads, increasing the traction on that reel. Meanwhile the right hand reel stays elevated and should be clear of its cork, resulting in the left reel ‘out-pulling’ the right and rewinding the tape: like a car in gear pulling against a car in neutral.

With no tape in the machine, both reel tables will naturally spin in opposite directions, as there is nothing to resist them. This is normal (at least on my model). The reason the tape does not get stretched in opposite directions is because one clutch is always closed while the other is always open. In stop mode both clutches should be open and the reel tables should stop against the brakes while the pulleys beneath them, containing the cork pads, continue to rotate unopposed.

I've found it can be useful to let the reels run free with no tape and no mode slected and try stopping them with your finger. If one takes considerably more stopping than the other, the pads on that side may be making contact when they shouldn't.

It’s a setup that depends on getting the right balance between the frictions on each clutch. I’ve never been able to get mine working spot on and it’s very temperamental. You may find when you’ve got the rewind working that it will begin to struggle part way through a big reel for example. Mine also has foam discs on the bottom of the reel tables, one of which is larger than the other. This seems to suggest that one clutch is designed to exert more torque than the other. I’ve tried swapping mine around, but I always run into some situation where one clutch will begin to struggle.

I’ll be interested to find out how you fare with yours. If you have some spare cork balls, I’d start by experimenting and filing them back to different heights and see what this does. Starting again at some stage may be inevitable, although incredibly frustrating as I know from experience! Others on here who know more about tape decks than me may have more specific advice about your particular model and it will be worth waiting to hear what they have to say.

I hope this helps.

Liam

[Lucien Nunes]

Consistent operation of the clutches depends on correct vertical movement of the reel tables between modes. Table height is adjusted by inserting or removing nylon shims of various thicknesses threaded onto the inner spindles. If some are missing or were previously fudged to allow the machine to work while it had collapsed friction pads, you might not get the proper vertical travel to suit your replacement pads while also avoiding the tape rubbing on the reel flanges. The service kit included a selection of shims for correcting the heights if necessary during maintenance.

[Voxophone]

It's also very easy to lose the shims when removing the reel tables, as they often seem to stick to the mounts or drop off the axles when these are drawn out. I'm pretty sure I lost at least one of mine which may account for some of the problems I've been having. Best to count how many you have and check every time you reassemble.

[Timvintage]

Thank you very much Liam and Lucien for your advice, that was all extremely helpful! I will have another experiment tomorrow. I did worry that it was possible that a shim or washer had got lost; Does anyone have any idea how many there should be in all? And also, is there something I could replace them with if there are any missing?

[vidjoman]

The number and thickness varies from one machine to the next - it was Philips way to carry out an adjustment for the correct clearance.

[Voxophone]

Mine had at least two per reel, possibly three. Unfortunately I didn't count them initially or I might have saved myself some problems! My model is an AG 8108 G.

[ricard]

Another option is that the grease in the mechanism inside the reel spindle could have hardened, so that the reel table is not dropping properly onto the spinning pulley as it should. This has happened to me a couple of times. There can be enough movement to get some rotation, but not enough for full traction.

If I recall correctly, on this model the right hand reel table will spin once the brakes have been disengaged, which is the result of the clutch used for ordinary forward drive in play/record modes, but not the left. So if the left reel is in fact spinning it sounds as if the friction pads are actually making contact with the spinning pulley below, but perhaps not with sufficient friction.

(On the mid-50's EL3510 Philips did have the left hand reel spin in play/record, but they dropped that feature on the EL3520 a few years later (and possibly earlier than that), I think because using a spinning disc like this tends to increase wow and flutter, as the tape tension will vary if there is any roughness to the drive. On three-motor machines it is more common, but a motor would provide a much smoother drag than a felt clutch and disc could. Single-motor Tandbergs use clutch of this type though on the left-hand reel, but not to create back tension, only to take up any loop that might form when the tape is paused.)

[Timvintage]

Thanks very much for that info Ricard, I did wonder if that could be possible about the grease.
I haven't had chance to take it apart again yet, however I did play a tape on it all the way through , to ensure that no further problems showed up. I did find out a couple of interesting things. Firstly I noticed that the playback was very stable, however seamed to play perhaps about a semitone too slow. Once the tape reached the end, I thought I would try pressing rewind, and to my surprise it worked! However fast-forward now wouldn't work. I'm guessing this must have something to do with the added weight on the right-hand reel now causing it not to turn? When I flipped the tape to play the other side, fastforward would work again but not rewind. Does anyone on here know for sure whether this could be because of dried grease, or whether it's to do with the pads etc? Any info will be much appreciated. Thanks so much!

[ricard]

When the pads are worn, or rather disintegrated, one symptom is that the reel drops quite far when pressing the corresponding wind button, i.e. a couple of mm. There's always a slight drop when going into wind mode, as the reel table is essentially lowered in order to make contact with the pulley (this is the opposite from Tandberg for instance, where the pulley is raised to mate with the reel table), but it should be in the order of half a mm or so (don't have exact figures). Another symtpom is a scraping sound if the pads are so worn that the reel table surface is making contact with the die-cast pulley rather than the pads.

If the reel tables don't drop when going into wind mode, or appear sluggish, that would indicate hardened grease.

This part of the recorder is not hard to dismantle: remove the top case, push the break arm out of the way and lift the reel table straight up, watch out for any washers or shims which might fall off. Press fast wind, and you should see the move down freely, even without the weight of the reel table.

If it doesn't move freely, the remedy is simple: pull the shaft straight up, clean it with some form of alcohol, the same goes for the hole through which it passes (I usually use Q-tips for this), add a dab of grease to the end of it, and put it back.

[IvorBlister]

Does anyone know the original composition of the clutch pads? I have a collection of 6 of these machines in various guises, 2 track, 4 track, stereo playback and the makes include Philips, Stella and Cossor. All use the same basic mechanism and all clutch friction pads have disintegrated. Looks like a mix of cork and rubber?? I made the first replacements by digging out the old goo and by using narrow laboratory orange rubber tubing which I carefully cut to length by putting the tube on a headless 6in nail mounted in a metal working lathe with a Stanley blade mounted on the tool post. These were glued in and the spool carrier drop distance shimmed up as appropriate. All worked fine for about a year but as I use the machine regularly eventually the heat from the valves dried out the rubber and it stopped rewinding. I have since used O rings in their place and this has proved to be a good solution and much quicker to do. I have always loved these machines since I first saw one in my junior school back in 1958/9.

[ricard]

I agree that when it ages it crumbles in a way that makes it look like cork, but I've seen an original one that had not disintegrated and looked like it was clearly made of homogenous material. Somewhere in the back of my head I'm thinking neoprene rubber, but I'm not sure where I got that from.

[WreckTangle]

For my first attempt to repair one of these machines I replaced the clutch pads with carefully trimmed ball valve washers. More recently I have used the stick-on pads sold by Dave Hughes whom it is good to see is still trading.

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

Really the shims need to be adjusted to suit the set-up after service which can take a long time and a lot of patience to get right. Watch out for tape catching on the edge of the spools if you don't get the set-up quite right.

[Happy to help]

What a blast from the past! I worked at Philips' service department (AES later CES) in about 1963, and repaired many EL3541s. I recall that the friction pads were a dark redish hardish rubbery compound with a convex top. As correctly mentioned above, you had to make several trial and error fittings of the neoprene type shim washers. I don't think that many of the clutches engaged all three pads with equal pressure, giving rise to a tug, tug, tug pull feel instead of a smooth pull. If anyone is interested, I have a complete EL3541chassis (no cabinet). I remember trying to fit a stereo head from a transistor model in about 1967. Never finished it nor touched it since.

Best regards,

Peter.