Leak Troughline Stereo Tuner

[Aubade65]

I am about to start on the restoration of this tuner that needs a bit of TLC. I have a couple of questions that someone more familiar with these tuners may be able to answer.
Firstly the tuner is still has its 2 core power cable with its American style plug fitted. The service manual states that a seperate earth should not be fitted presumeably to prevent earth loops. I want to use a 3 core power cable and not have to rely on the AF cables to provide a safety earth. The mains input circuit looks conventional so is there any good reason not to connect a mains earth?

Also the tuner needs some attention to remove rust from the top of the chassis particularly under the tuning gang and the troughline which need to be removed to treat the rust. I have found however that it is impossible to shift any of the self tapping fixing screws - good or rusty. Is there any special knack to removing them or are they fitted with a massive amount of torque to ensure good electrical contact?

[vidjoman]

Quote - The service manual states that a separate earth should not be fitted presumably to prevent earth loops.

I had that problem with one of these and a 3 core lead and connected to a Leak Stereo 30 amp. Radio was ok but the Phono input hummed loudly and was unlistenable. Took off the earth from the tuner and it cleared.
The 2 core lead and American type plug would be to go into one of the Leak amps of that era.

[PJL]

Wire the earth to chassis and try it. If you plug the amp and tuner into the same extension lead it should be OK.

[bikerhifinut]

If it is in working order still, I would be very reluctant to disturb the tuning parts. I have a couple of Troughies and one of them has a fairly corroded looking trough but as it works just fine I leave it be. remember if you pull the RF and IF parts out theres every chance it will need a full re alignment on re building it.
As to earthing the chassis, i wonder if the use of an earth lift resistor would help if you do get any hum loops? Although that usually only works if the signal ground is separated from chassis ground. As you really should have chassis at earth potential.

A.

[Aubade65]

Thanks for the replies.

I do not have a Leak amp to plug the tuner into - I bought it as a standalone tuner either to use with a headphone amp or as a source for some of my AM radios. I will replace the power cord with a 3 core one to provide a mains earth. If this proves troublesome I will put the the 2 core back and use a direct to ground earth as I have with the RA17.

I am not sure if I will be able to release the self tapping screws so I will leave the tuning gang in place, cover up the valve holders and flood the top of the chassis with WD40 while giving a good rub with some Scotchbrite pads which should get rid of most of the rust and give some protection for the future.

I hope that I will not have to undo any of the self tappers in the future.

[Sideband]

Originally Posted by vidjoman

The 2 core lead and American type plug would be to go into one of the Leak amps of that era.

...which is exactly how mine is connected to a Leak Delta 70. Never bothered to fit an earth to mine and it's been fine for years.

[Records]

Dont put WD40 anywhere near it, horrible stuff, will do more harm than good.

[MrElectronicman]

I have the same tuner and It was fitted with a 2 core lead in order to prevent ground loops. The Earth is intended to be provided by the audio cables from the Amp.

As bikerhifinut stated, I too would not disturb the tuning section if it is working, because if you touch the Troughline you may have a hard time getting it to work again, unless you know how to realign it.

Right! WD40 NO WAY

[petertheorgan]

I have the same tuner too, it was designed to have a 2 core mains lead and mine too plugs straight in to the back of my leak stereo 70 amp ,
its worked perfectly for the last 30 years ,
but then I am a lover of vintage electrics !

[Aubade65]

This unit is going to be used as a standalone unit not with an associated Leak amplifier. It seems to have been damaged probably by water as there is extensive corrosion on the top of the chassis including the area around mains transformer and the rectifier. So with the combination of potential safety issues and 50+year old design standards I would rather not trust a couple of RCA phono connectors to provide a safety earth but to use an earth either via the mains or to a dedicated earth line if there should be an issue with earth loops.

Also there seems to be an issue with using WD40 to deal with rust. I do not intend to dump the whole unit into a bucket of the stuff but to liberally apply some to the corroded areas and remove the rust by rubbing the surface with an abrasive pad. Once the rust has been removed it can be protected from future corrosion by applying a thin film and allowing it to dry. This technique has mentioned several times by posts on this forum.

There also seems to be some suspicion around the troughline which is little more than a tube with a wire through the middle which provides a very stable inductor for the local oscillator - it is probably easier to maintain than the equivalent wound coil

[vidjoman]

How many times does WD40 come up as good for almost anything? It's only white spirit, 5% light oil & 1% perfume, according to their data/health & safety sheet that was sent to me some years ago. The name of WD seems to originate from Water Displacement which is how it was marketed.
I do use it occasionally but only to free up some parts where I don't need lubrication but I could just as easily used white spirit

[Geoff 555]

Hello I would recomend Plusgas, it has freed off some very heavilee corroded parts and to hold any corrosion try some Ballistol, warning it doesnt half stink until it goes off. Have used it for years and it works for me.
Best of luck.
Geoff.
Not WD 40 please.

[paulsherwin]

Originally Posted by vidjoman

How many times does WD40 come up as good for almost anything? It's only white spirit, 5% light oil & 1% perfume, according to their data/health & safety sheet that was sent to me some years ago. The name of WD seems to originate from Water Displacement which is how it was marketed.
I do use it occasionally but only to free up some parts where I don't need lubrication but I could just as easily used white spirit

One thing you can use it for is to clean and rustproof a metal chassis. I would think carefully before doing this though. WD40 rustproofs by evaporating to leave a thin layer of mineral oil over the surface, and this will attract dirt and dust.

Corrosion will develop very slowly in a dry and heated domestic environment. If you are really bothered about corrosion, you should remove it all and possibly paint the surface.

Plus-gas is indeed a good dismantling fluid and much more effective than WD40 for that application.

[PJL]

I use bike 'lubricant' sprays like GT85 from Halfords which is a good solvent for removing dirt, wax and grease and the residue is not like the sticky goo left by WD40.

[G6Tanuki]

Originally Posted by vidjoman

How many times does WD40 come up as good for almost anything? It's only white spirit, 5% light oil & 1% perfume, according to their data/health & safety sheet that was sent to me some years ago. The name of WD seems to originate from Water Displacement which is how it was marketed.

"WD40" is a *brand*, not a single product; there's a whole range of WD40 products available. Saying "WD40" is like just saying "Ford" when talking about vehicles or "Heinz" when talking about food.

http://www.wd40.co.uk/wd-40-specialist/

Some WD40-branded products may be appropriate to a task, others not.

[Silicon]

You are probably aware that removing the rust with a dry scotchbrite pad will create a lot of dust which may harm components such as the variable capacitor.

Instead of wetting the pad with WD40, I would use a rust converter fluid such as Jenolite or Kurust. The non-drip version of Jenolite would be less likely to go where it is not needed.

[chriswood1900]

I have many times had to resolve earth loops on HiFi equipment and adding an earth rarely helps, however, there is greater need now to ensure it is safe than use to be the norm. Using quality connecting leads should be OK as Leak intended as long as you don't disconnect them whilst the units are on. I have on occasions run a separate earth but via the amplifiers earth rather than direct to a plug. I think the problem you have to keep in mind is that some of the components like the transformer particularly as it may have got damp when it was suffering corrosion could be leaky to earth and create a danger. One solution to minimise danger could be to allow the leads to earth it to the amp but use a plug with an integral RCD.
Chris

[Records]

As you say WD40 is a brand and in a lot of cases when people say they are going to spray WD40 all over something it is the original product which as already mentioned is a water displacement spray, it dries up leaving a nasty sticky film that does more harm than good.
Ive seen people use it to clean out volume pots, all it will do is attract more dirt and make the pot a sticky mess

[julie_m]

Aye.

The worst thing about WD40 spray is, it usually does make things work a bit better -- but only for awhile .....

[Aubade65]

If it leaves such a sticky mess though not in my experience when used for storing metal items, why was it originally developed to protect Atlas ballistic misslies?