Repairing a 'Bowden' Cable in a Panasonic Music Centre

['LIVEWIRE?']

Apologies if 'Bowden' is not the correct name. This is the mechanical cable link between the record/playback slide switch and the record lever in a Panasonic M/C which has seized up so that the switch remains in the 'rec' position regardless of whether this function is selected or not. At the lever (deck) end the slide mechanism moves, but at the switch end it's stuck fast.
Can this fault be rectified, and, if so, how? The switch itself wotks as it should.

[terrybull]

If it is similar to a cycle brake or gear cable then Bowden is indeed the correct name. I have no experience of the item you are repairing but I have almost 50 years knowledge of restoring and repairing vintage and modern cycles. If you can post a couple of pictures that would help. If you can remove the cable then it may be possible to free it by pulling the inner back and forth through the outer and feeding oil down it. I may be able to supply a suitable replacment but would need to see a picture to say if this is possible.

If you need a push pull movement then standard bicycle cable outer combined with solid piano wire inner (from model shops) is what you need. Net curtain 'wire' is also a good outer for bowden cables. Net curtain wire being of simple round wire construction is a lot easier to cut than bicycle outer as this has a rectangular wire instead (no gaps for the cutters).

[Nickthedentist]

All true, but these things are tiny - much less than 1/8" overall diameter usually.

I would take it right out of the machine and dribble WD40 between the inner and outer, then leave it for a day or so. With luck, the inner will work free and you'll be able to wipe off the excess lubricant and re-install.

If this fails, you may have to replace it with something similar salvaged from another piece of audio equipment from the same era.

Nick.

['LIVEWIRE?']

This 'cable' is actually flat, unlike a Bowden Cable. Each end is terminated in a plastic housing containing a metal pin which engages with the switch. I'll post a picture or two ASAP, and will also try dribbling WD40 into it, then try it to see if that frees up the slider.

[Nickthedentist]

I know the kind of thing, often a fetching shade of blue.

I still think it's essential to separate it from the machine, so that you can tell for certain whether it's the cable that's binding, or the things that it's attached to at either end.

I'd be surprised if the flat metal strip could actually bind within the plastic outer - it doesn't seem possible.

Nick.

[Gillian]

The most common fault ,I have found with these remote slide switches is that the pin on the switch is not properly engaged to the drive strip.
The switch end of the drive will usually unclip .Then carry out a full switch cycle until the slot in the actuator lines up with the slide switch, then reassemble.
As Nickthedentist says ,failure of the drive to the switch is uncommon.
Gill

['LIVEWIRE?']

In this case it's the slider on the cable which is binding. I'd already separated it from the switch, which can be easily manually operated) before posting my enquiry.

[Nickthedentist]

Apologies if my advice came across as patronising - it wasn't meant to be.

Have you tried some PTFE spray lubricant e.g. the one Servisol sell?

Nick.

['LIVEWIRE?']

I didn't mean to imply that I thought your reply patronising, Nick. I was hurriedly replying as I had an appointment to keep. I always find replies to my queries on this and another forum helpful, and hope my answers to others enquiries are likewise. As to the PTFE lubricant, no I haven't tried it, since I don't have any. No doubt the likes of CPC stock it. What particular product name or nuber should I be looking for?

[Nickthedentist]

It's called Super 200:

http://cpc.farnell.com/1/1/33634-sup...-servisol.html

Nick

['LIVEWIRE?']

Thanks, Nick. I've cured the fault on this occasion by dribbling WD40 into the mechanism, so the Rec/PB switching on this M/C now works as it should, after having also replacing a broken record prevention lever with one taken from an almost identical Cassette mechanism. I guess such problems are only to be expected with a set about 36 years old!!
I'll add Super 200 to my next CPC order for future use, though. Incidentally I also use Servisol 'Super 40' from time to time. Haven't compared the two, but would I be correct in thinking that Super 40 is basically Servisol's version of WD40?

A thought, is the outside clamped properly? This would lead to one end moving and the other not.

['LIVEWIRE?']

I'll double check that, Merlin. The switch & cAble assembly was working OK yesterday afternoon, but best to make sure before refitting the cabinet & turntable to the M/C. Not a 5 minute job to take it apart again!

[camtechman]

I have a Philips EL3585 (mini upright R2R) which uses a thin bowden cable assembly to operate the record/playback switch.

In my case the inner twisted wire has broken about 1/3rd along it's length, due to rubbing on the inner metal spiral of the plastic covered sheath.

This is due to the route the cable assembly has to take through the chassis & components which involves a 30deg bend !

I found a suitable twisted wire at my local fishing tackle shop, it's a 28lb breaking strain Pike fishing wire !! It's also plated with a matt black friction reducing coating.

Each end of the wire has to be soldered to two eyelets, which are then located/held by two metal forks - one on the switch lever & the other by the record botton

However, as yet, I've not been succesful in getting the solder to strongly bond the wire to the eyelets and then take the pulling strain of the switch operation.

After a couple of operations, the wire pulls out of the eyelets. It may require a 'stronger' solder (silver solder or a high melting point type ?)

I'm not sure if this will help with your problem but it's worth putting in your "grey matter's" memory file.

[Nickthedentist]

The Philips ones tend to be proper mini-Bowden cables, as opposed to the flat, Japanese ribbon affairs.

Also used on their subchassis record decks to link the speed change and cueing levers to the bits they control.

N.

[G6Tanuki]

For "proper" Bowden-cables, whether of the push-pull or rotational flavours, I can recommend these guys:

http://www.speedycables.com/

They're more used to doing car and motorcycle speedometer/tachometer/handbrake-cables but in times-past they've managed to sort me out with a fix for a remotely-cable-controlled coil-bank on an aged Marconi transmitter [think PO-style ratchet-one-step-with-each-pulse uniselectors at one end, something like a 1950s TV turret tuner at the other].

Originally Posted by camtechman

inner metal spiral

surely that is a helix?

[camtechman]

I thought they made pencils ?

[sp10mk11]

I remember these cables being used extensively in Technics amplifiers in the 80s, I never had trouble with any of them other than cleaning the switches they operated.

not much help I know

Gary