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Green Goo

Discussion in 'classic' started by kevinrt, Jun 23, 2022.

  1. kevinrt

    kevinrt pfm Member

    I read about some folk encountering green goo on the wiring when restoring some older equipment.

    Is this a problem that needs to be remedied or is it just unpleasant to work with wiring coated in this stuff?

    I noticed some on my TD124 and wondered if I should make plans to sort it out or just ignore it.

    regards

    Kevin
     
  2. Tony L

    Tony L Administrator

    Where exactly on the 124? Are you sure it isn’t just oil spill? It seems most 124s have at some point had the main bearing over-filled and suffered an oil-spill which can get into the wiring that is routed under the platter. I totally stripped my MkII down to thoroughly clean everything but didn’t feel I needed to replace any wiring. It cleaned up ok. I’m obviously not using the original two-core bell-wire mains cable as it isn’t to current safety standards (I’m using a modern earthed cable), but everything else is original wiring-wise.
     
  3. kevinrt

    kevinrt pfm Member

    I found it where the wires coming out of the motor joined the first circuit board. It looked very much like the pictures posted on some of the threads here. It was on the outer ?plastic covering of the wires towards the ends and on the solder where the wires joined the circuit board.

    Kevin
     
  4. Tony L

    Tony L Administrator

    [​IMG]

    This is pretty much where mine is, I may have cleaned it up a bit more. There were certainly some issues with what was either oil that had got in there, or maybe decomposition of the clear PVC shrinking (you can see some gloop in one in the pic). I spent a fair bit of time cleaning stuff up with isopropyl and got it looking a heck of a lot better than it started. I couldn’t be bothered stripping it all out and redoing it from scratch. I didn’t see any reason to. There was certainly no cracking or fractures in any of the wire coating, it just felt a little damp/sticky in places, which I suspect was largely old main bearing oil and it did seem to clean off.

    My deck is properly grounded to mains earth via a three core mains lead that goes to both the chassis and the motor case, so if anything does ever go bad it will just pop the 3 Amp fuse in the mains plug. I really can’t see that as an issue as all the original cable coating still seems solid and flexible. It was just filthy with a sticky gunge.

    I would personally not be prepared to use a vintage turntable or valve amp that was not grounded to modern mains specification. Whatever you do I’d strongly recommend grounding the chassis and motor case. The Thorens method of expecting the arm to do this just isn’t safe IMHO and I’m sure it wouldn’t pass a PAT test.
     
  5. kevinrt

    kevinrt pfm Member

    So it’s OK to clean it up as much as possible then just ignore it?

    Mine had already had its mains input changed pretty much identically to yours when I bought it.

    Kevin
     
  6. killie99

    killie99 pfm Member

    miktec likes this.
  7. Tony L

    Tony L Administrator

    I suspect it is a case by case thing. My suspicion with my particular TD-124 is if there is PVC decomposition it is limited to the clear additional shrink coating over a couple of the wires. I can’t remember what exactly I did as the above is a picture whilst I was taking stuff apart so I could see how to put it back together again. I think I was under the impression it was oil at the time so cleaned up as best I could. If I go in again I’ll simply remove and replace that clear additional layer with fresh heatshrink rather than doing a full rewire. The motor windings seemed perfectly ok from what I could tell, obviously the only option there would be to replace the coils (which is doable, Audio Silente make replacements).
     
  8. miktec

    miktec unissued


    I recently opened up a Yamaha active speaker set (bought late 90s) to extract the speakers and something similar had happened to the sheathing around the internal interconnect bundles - sticky as the stickiest sticky bun!! - unpleasant experience trying to get it off my fingers.
     
  9. Tony L

    Tony L Administrator

    Thinking about this some more I will rewire my TD-124. I’d made all inspections so far assuming it was an oil spill/filth, it hadn’t actually occurred to me it could be the wires themselves decaying, so at the very least I need to reevaluate it with fresh eyes. I’ll not do it immediately (the weather is too nice so I’m out cycling!), and I’m really hoping I don’t need to replace a working set of motor coils, but I’ll certainly redo all the black wires, remove any clear PVC coating (I’ll replace with modern heatshrink) etc.

    I’m hoping the double-coated two core mains wire from a typical figure of eight plug mains cable (the sort of thing one uses with a ghetto blaster, cassette deck etc) will fit as that wouldn’t look too different to what is there and would get it closer to modern wiring standards. I have a good supply of those knocking around.
     
  10. Vinny

    Vinny pfm Member

    Almost certainly "rewritten" for the layman.

    By far the most common plasticisers are phthalate esters. All esters are unstable insofar as they exist in equilibrium with water (moisture) and their parent acids and alcohols.

    For instance - ethanol and acetic acid react to form ethyl acetate (an ester and a reasonably common solvent as part of cellulose thinners), plus water. But there are always traces of methanol and acetic acid around if moisture is present, which there almost always is.

    Dimethyl-phthalate (a common plasticiser) is the product of the reaction of methanol and phthalic acid. Same logic applies.

    The free acid will react with the copper. The goo is quite possibly glycol (an alcohol), or glycol derivative, and also used to make phthalate esters.
     
  11. kevinrt

    kevinrt pfm Member

    Hi Tony

    I’m sorry I have caused you to start re-evaluating those wires hidden away under your plinth. It niggles away once you start thinking about it. Probably would have gone on for decades with no issues.

    What is the purpose of the additional layer of clear plastic over the wires?

    Regards

    Kevin
     
  12. Tony L

    Tony L Administrator

    To be honest I’m not sure. May be additional isolation, identification, or even strain relief. It seems inconsistent and I’ve yet to find a really nice neat easy to understand wiring diagram for the TD-124. When I do it I’ll have to ping everything out with a multimeter and draw my own idiot map.

    There are obviously three distinct connected areas; a) the mains and motor connection as pictured, b) the power switch and suppression capacitor (which I replaced years ago), and c) the neon strobe light. I’m pretty sure the beige resistor with the yellow sleeve in the picture drops voltage to the neon bulb elsewhere in the deck, so I guess it might even generate some heat which may explain the extra layer of PVC sheaving. I’ll obviously transfer the resistor to the new loom.
     
  13. kevinrt

    kevinrt pfm Member

    I may replace my motor coils at some point.

    When I transported my TD124 home after buying it I found the motor had stopped running. On inspection I saw that the red wire from the motor had sheared at the point where it was soldered to the little board pictured above. Presumably due to the motor wobbling about on its springs during transport. There certainly couldn’t have been much slack on that wire as it was too short to just re-attach. I had to add an extra extension to the wire to make a repair and as my soldering is a bit shaky at the best of times it niggles me knowing that it’s under there. Especially with the goo as well.

    Do you know of anyone within easy reach of Oxford who is experienced with working on these turntables?

    regards

    Kevin
     
  14. Tony L

    Tony L Administrator

    Guess who’s TD-124 is in bits across the floor again…

    The black two core wire is absolutely disgusting, far worse than I realised. Oozing foul green sticky goo at every exposed end. The motor wiring had some very slight hints, but it doesn’t seem to extend more than about a mm beyond the exposed end so I’m counting that as being ok. I’ve trimmed it back by that amount and re-tinned the ends. Black two core wire now in the bin. Every terminal desoldered and cleaned. Next step is to see if I can put everything back together again…
     
  15. chiily

    chiily PFM Special Builder

    It is really horrid stuff, sticky and insipid. I rewired the STA15 because some of the wires were physically wet with goo, dripping on to the wires below them, and at some solder joints eating enough of the cooper wire to break the connection...horrid mess.

    Good luck Tony.
     
  16. killie99

    killie99 pfm Member

    The reason I know about this is that my parents home which was built in the late 60’s had the green goo seeping out of the wall sockets!
     
  17. Fergus

    Fergus pfm Member

    I’d have called Ghost Busters!
     
    MUTTY1 and Snufkin like this.
  18. Tony L

    Tony L Administrator

    That was a really disgusting and long job! I’ve only just finished, so a full day job at the speed I can work. I’m sure it had got a heck of a lot worse since I last did major work on this deck. The areas around the switch and neon were obviously wet with the green ooze and it had dribbled onto other enclosed parts. Anyway it is now done and there was a refreshing absence of fire etc. Even goes round the right way. The hard bit as ever was getting all the sizing and routing right. I’ll post a few pics on my 124 thread later, though I didn’t think to get anything that really captures the green ooze. As ever my pics are more about being able to put it back together again in the right order.
     

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