Continuing the Television theme …

[Michael GilliganParticipant @michaelgilligan61133]

I have just spent a very frustrating afternoon doing a five-minute job !

When I moved to North Wales, I just plonked the LG television on a convenient shelf, and didn’t bother installing it.

A couple of weeks back, I tried plugging a shiny new coax antenna-lead into the socket … “oh deary me” says I [or words to that effect], the plug doesn’t fit the socket and it feels like I will break the circuit board !

Returning this afternoon with an assortment of leads gathered from my hoard [the original, of course, having been left in-situ at the old house] … not one of the plugs fits the TV !

As luck would have it … I also had a ‘Trade Pack’ of loose plugs from MAXVIEW and Yes these fit beautifully.

 

So … my question for the forum is: Is there a dimensional standard for these plugs and sockets, and if so, how tightly toleranced is it ???

I rather suspect that some evil ‘rounding’ has crept-in with metrication

MichaelG.

.

Edit: __ For the benefit of anyone else hitting the same problem:

[bernard towersParticipant @bernardtowers37738]

Smacks of lets make this a bit different and they will have to buy from us

[peter1972Participant @peter1972]

The plug diameter should be 3⁄8-inch (9.525mm). I have not found what the diameter the inner pin should be.

https://en.wikipedia.org/wiki/Belling-Lee_connector

[peter1972]

On peter1972 Said:

The plug diameter should be 3⁄8-inch (9.525mm). I have not found what the diameter the inner pin should be.

https://en.wikipedia.org/wiki/Belling-Lee_connector

Thanks, Peter … I will measure the two inner pins tomorrow

[need to dissect the non-fitting one]

MichaelG.

 

[SillyOldDufferModerator @sillyoldduffer]

Yer tis’

I’ve got loads of them, so will measure a few.  Quality varies enormously.   The LG problem might be the female – they’re spring-loaded in various ways to grip the plug, ranging from cheap and nasty slots to elaborate clips.   Possibly the LG has a strong spring and needs a lot force to open it.  The chamfer on the plug that opens it isn’t specified…

Why is nothing ever easy?

Dave

[Mark RandParticipant @markrand96270]

It’s a real shame that tellies and wirelesses didn’t standardise on 75Ω BNC connectors instead of the weird rather non-conductive aluminium VHF connectors. Of course, having said that, I had problems with silver plated BNCs in coal fired power stations. Silver sulfide is a lousy conductor at mV levels…

[Robert Atkinson 2Participant @robertatkinson2]

BNC’s were orders of magnitude more expensive than the “Belling Lee” in the 50’s and 60’s when TV’s first became popular. No contest for a cost sensitive market.

[SillyOldDufferModerator @sillyoldduffer]

I much prefer BNC too, though 50 rather than 75Ω.   (There is an engineering reason.)

The Belling Lee connector has many virtues though as a consumer plug/socket that’s not continually being pulled in and out.   They’re cheap, easy to wire, reasonably robust, and perform acceptably up to about 1GHz.   And if a radio ham uses one to transmit power, they’ll handle up to about 150W without melting!

BNC provide a secure lock and support repeated disconnects, have better RF performance, often silver-plated, but are pricey and harder to wire.  Back in the day BNC was very expensive compared with Belling Lee, not so bad now.

I’ve not much experience of them, but F-connectors seem a good consumer compromise: cheaper than BNC and more secure than Belling Lee.   None of my equipment has an F-socket!

Worst of all in my experience are the PL259/SO259 range.   Allegedly UHF, but not good and they’re difficult to wire, including fun and games with the reducers needed to take different diameter coaxes.  Main virtue is a well-made one will handle a kilowatt of RF.  Unfortunately many of them are cheap and nasty.

Looking up Belling Lee to find the dimensions revealed several oddities!  It’s claimed the connector was invented in 1922 which is odd because Americans believe they invented coaxial cable in 1931!  If 1922 is real, rather than a typo for 1932 or 1942, then what cable did Belling Lee’s plug/socket connect?  Coaxial cable existed in the 19th century, say 1860, but only in rigid form – a central wire spaced inside a rigid copper pipe, not flexible as we’re used to.  Flexible only became practical  with plastics developed in the 1930 and 40s.   So what cable did Belling Lee use in 1922?  Whatever it was, only expected to work up to 1.6MHz (Medium Wave radio), so the plug working up to 1GHz is a triumph!  Americans also believe we call it a PAL connector: maybe on the continent, but never heard it called that in the UK.

As an aside, does anyone know what the coax connectors used by the UK military during WW2 are?   Sockets very common on surplus equipment, but plugs were hard to find.   Like this example on a 19 Set Variometer:

UK WW2 coax connectors disappeared fairly quickly after the war.  Maybe they weren’t very good, or possibly, it was realised standardisation was important: all NATO equipment should take the same cables, so a US cable could be used to connect a UK radio and vice-versa.

Dave

 

 

 

 

[SillyOldDuffer]

On SillyOldDuffer Said:

Yer tis’

I’ve got loads of them, so will measure a few.  Quality varies enormously.   The LG problem might be the female – they’re spring-loaded in various ways to grip the plug, ranging from cheap and nasty slots to elaborate clips.   Possibly the LG has a strong spring and needs a lot force to open it.  The chamfer on the plug that opens it isn’t specified…

Why is nothing ever easy?

Dave

On SillyOldDuffer Said:

Yer tis’

I’ve got loads of them, so will measure a few.  Quality varies enormously.   The LG problem might be the female – they’re spring-loaded in various ways to grip the plug, ranging from cheap and nasty slots to elaborate clips.   Possibly the LG has a strong spring and needs a lot force to open it.  The chamfer on the plug that opens it isn’t specified…

Why is nothing ever easy?

Dave

Many thanks for the drawings, Dave !

… and for your offer of some sample measurements.

MichaelG.

.

Edit: __ This is an earlier model of LG TV … but I am taking it as circumstantial evidence of their build-quality:

[Michael GilliganParticipant @michaelgilligan61133]

In my present enfeebled state, I dare not risk taking the TV off its shelf, but I’ve managed to get a snapshot of the female connector … confirming Dave’s assumption:

.

.

MichaelG.

[SillyOldDufferModerator @sillyoldduffer]

As promised some measurements.   I’m surprised!

Be warned: don’t read this if you like to believe British made stuff from yesteryear is high-quality compared with modern rubbish!

Here are the examples:

1. 1950/60 British.

2.  Modern plastic, circa 2000.

3.  1970-ish British, Aluminium, very common (2 examples):

4.  Metal recent, foreign made:

In general these are not precision made!  The pins and bodies are not round, and sizes vary considerably on the same plug and in comparison with others.

1950’s British, with silver plate.   Body 9.32, 9.46, 9.40, 9.55, variance 0.23mm.   Pin 2.40mm

1970’s Aluminium.  British. Corroding.

• Example 1: Body 9.54, 9.59, 9.55, 9.52 variance 0.07mm.  Pin 2.35, 2.33, 2.32, 2.37 variance 0.05mm.  Crudely threaded, hard to assemble
• Example 2: Body 9.46, 9.45, 9.47, 9.46 variance 0.02mm.  Pin 2.49, 2.35, 2.41, 2.37, variance 0.14.  Clean thread,

Plastic Modern circa 2000:  Body 9.53, 9.56, 9.54, 9.47 variance 0.09mm.  Pin: 2.37

Metal Modern, recent purchase:  Body 9.49, 9.48, 9.47. 9.50, variance 0.03mm  Pin: 2.36, 2.26, 2.25, 2.26 variance 0.01mm

These plugs aren’t made to high tolerances!  Though they look similar one British Aluminium plug is more accurately made than the other.

And although the silver-plated plug looks good, it’s dimensionally poor compared with the Aluminium plugs.  The plastic modern plug is slightly worse than them, but the best is the recent purchase.

Body dia should be 9.525mm.  Mine are mostly under that, except for a couple of fat spots, probably due the body not being round.

Pin should be 2.35mm.  Again, my examples are mostly undersized, with a few fatties.

Conclusion:   with one exception, possibly lucky, my sample plugs clearly aren’t precision made!  Therefore expect some loose and some excessively tight fits.   I guess Michael’s TV has a sprung tight socket, and his plugs are all fatties apart from the Maxviews.  I must have used hundreds of Belling Lee plugs over the years and not had a problem, but…

Dave

 

 

 

[John HaineParticipant @johnhaine32865]

The horrible Balling Lee coax connector seems a British thing.  I notice that the LG TV pictured has what I think is an F-type connector for a satellite input next to the Belling Lee.  I’ve had an FM/DAB tuner that also had an F-type.  Time the BL connector was consigned to the dustbin of history as the F types must be pretty cheap.

[Michael GilliganParticipant @michaelgilligan61133]

Further to Dave’s very informative measurements …

The central pin [actually a tube] on this particular batch of MAXVIEW Plugs measures only 2.24mm … bulging very slightly to 2.25mm where tip has been worked.

The ‘oversize’ pin on the ready-made lead measures 2.36mm … bulging very slightly to 2.37mm where tip has been worked.

The large diameter is 9.46mm on both.

I must therefore conclude that the underlying problem is indeed the socket that LG uses … which is fortuitously ‘just right’ for the undersize pin.

 

Just to emphasise: The socket would probably accept a full-size pin if you push hard enough, but I was not willing to take that risk … and a look at the video I posted earlier would suggest that the risk is significant.

MichaelG.

[Nicholas FarrParticipant @nicholasfarr14254]

Hi MichaelG, I have a LG DVD recorder/player, and the antenna socket’s outer is 9.48mm on the inside, but only 9mm between the two sets of flat springs, three of which can be seen at 12, 3 and 9 o’clock in my photo below held in place by a cage affair.

The shank of my No. 44 twist drill, which is 2.13mm in  diameter, will fit snugly in the central socket. but my number 45 twist drill shank is 2.53mm in diameter, and takes a little bit of pressure to push in. I have a couple of unused plugs, but bought from Homebase many years ago, which are not unlike the one in Dave’s bottom photo, with the body having an outside diameter of 9.48mm, and a pin size of 2.23mm in diameter, and these take a small amount of pressure to push in, which is to combat the the pressure of the four springs and the split pin tube, but the socket is firmly fitted to the casing.

Regards Nick.

P.S. this machine doesn’t record or play DVD’s as the video laser has failed and replacements are no longer available, but it will still play music CD’s, and has Scart input and output sockets, which is handy for connecting up other equipment, as and when needed.

[Michael GilliganParticipant @michaelgilligan61133]

Thanks for the close-up of LG socket, Nick

Yes, the design-concept looks quite good [if mounted firmly]

… shame that the insertion force is so high when they are so flimsily mounted on the TeleVisions.

MichaelG.

.

Incidentally, the fly-lead from which I was obliged to remove the plug was JVC branded, and very nicely made.

[Russell EberhardtParticipant @russelleberhardt48058]

I’ve always found a very fine smear of silicone grease helps a lot with these connectors, especially with elderly slightly oxidised ones.

Russell

[VicParticipant @vic]

I had cause to use many types of TV and Audio connectors in my last job. The best quality coax connectors that I came across were a right angle type with cast aluminium bodies. They seemed well made and easy to wire.

[SillyOldDuffer]

On SillyOldDuffer Said:

I much prefer BNC too, though 50 rather than 75Ω.   (There is an engineering reason.)

The Belling Lee connector has many virtues though as a consumer plug/socket that’s not continually being pulled in and out.   They’re cheap, easy to wire, reasonably robust, and perform acceptably up to about 1GHz.   And if a radio ham uses one to transmit power, they’ll handle up to about 150W without melting!

BNC provide a secure lock and support repeated disconnects, have better RF performance, often silver-plated, but are pricey and harder to wire.  Back in the day BNC was very expensive compared with Belling Lee, not so bad now.

I’ve not much experience of them, but F-connectors seem a good consumer compromise: cheaper than BNC and more secure than Belling Lee.   None of my equipment has an F-socket!

Worst of all in my experience are the PL259/SO259 range.   Allegedly UHF, but not good and they’re difficult to wire, including fun and games with the reducers needed to take different diameter coaxes.  Main virtue is a well-made one will handle a kilowatt of RF.  Unfortunately many of them are cheap and nasty.

Looking up Belling Lee to find the dimensions revealed several oddities!  It’s claimed the connector was invented in 1922 which is odd because Americans believe they invented coaxial cable in 1931!  If 1922 is real, rather than a typo for 1932 or 1942, then what cable did Belling Lee’s plug/socket connect?  Coaxial cable existed in the 19th century, say 1860, but only in rigid form – a central wire spaced inside a rigid copper pipe, not flexible as we’re used to.  Flexible only became practical  with plastics developed in the 1930 and 40s.   So what cable did Belling Lee use in 1922?  Whatever it was, only expected to work up to 1.6MHz (Medium Wave radio), so the plug working up to 1GHz is a triumph!  Americans also believe we call it a PAL connector: maybe on the continent, but never heard it called that in the UK.

As an aside, does anyone know what the coax connectors used by the UK military during WW2 are?   Sockets very common on surplus equipment, but plugs were hard to find.   Like this example on a 19 Set Variometer:

UK WW2 coax connectors disappeared fairly quickly after the war.  Maybe they weren’t very good, or possibly, it was realised standardisation was important: all NATO equipment should take the same cables, so a US cable could be used to connect a UK radio and vice-versa.

Dave

 

 

 

 

The WWII connector is called a “PYE” connector after the Cambridge company that made them. The male part on the Variometer in your picture is a 10H/528. The mating female in right angle style is a 10H/702. I think the last bit of kit they were used on was probably the RACAL RA17

Robert.

[Russell Eberhardt]

On Russell Eberhardt Said:

I’ve always found a very fine smear of silicone grease helps a lot with these connectors, especially with elderly slightly oxidised ones.

Russell

You should avoid silicone grease on electrical contacts. A receiver antenna connector is not too bad but anything where there is a chanve of arcing it can turn to glass and ruin the connection.

Vaseline is a better choice.

Robert.

[MacolmParticipant @macolm]

Yes, avoid silicone (and this includes RTV) anywhere near low contact force connectors and slip rings. Once contaminated, there is no simple means to clean the surfaces, and you may never recover reliable contact.

Silicone grease can be satisfactory to waterproof spade connections on cars, but is still liable to get where you do not want it. As well as spoiling contact, it also spoils adhesive bond integrity.

[Phil PParticipant @philp]

My dad used to drill it into me from a young age that you must keep your car battery terminals well lathered up with Vaseline to maintain a good electrical connection, and I always have done since.

It does seem strange that when you google the properties of Vaseline, it is described as an insulator.

Phil P

[Phil P]

On Phil P Said:

My dad used to drill it into me from a young age that you must keep your car battery terminals well lathered up with Vaseline to maintain a good electrical connection, and I always have done since.

It does seem strange that when you google the properties of Vaseline, it is described as an insulator.

Phil P

Counter-intuitive rather than strange!   The good comes from a mix of lubrication allowing a tighter fit whilst the grease also keeps water and air away from the joint.  When a plug is shoved into a socket, or a clamp tightened on a battery, the vaseline is squeezed out of the way wherever good metal-to-metal contact is made, but it leaves a dam at the edges and fills all the crevices, preventing corrosion.   Not perfect, because it insulates, but a good example of a simple cheap measure that works well and is harmless.

A few posts mention Silicone sealants & greases have disadvantages.   Very true, but in practice they can work well too.  Generally I avoid them, but they’re not always inappropriate.  Horses for courses, and choose the right product.  Luck plays a part;  misuse doesn’t matter if the circumstances mean that the ill-effects of using Silicone take years to appear!

Better than Vaseline is available for protecting terminals.  Conductive greases, usually loaded with Copper or Carbon, and some of them are Silicone based.  Search for Dielectric and Conductive Grease on the web.  Halfords and  motor shops sell it too.  I normally use Vaseline because it’s available and ‘good enough’.   The better products are appropriate when the electrics are more exposed, like a scrambler motorbike raced on a sea-shore.

Dave

 

 

 

 

[Robert Atkinson 2Participant @robertatkinson2]

Vaseline is an insulator but it keeps moisture and air out of static connections like car battery terminals reducing corrosion. For moving contacts it also lubricates. Less corrosion means lower contact resistance.
What it doesn’t do is turn into silicon dioxide, AKA glass which silicone oil / grease can.

Robert.

[John HaineParticipant @johnhaine32865]

It might be an urban myth, but back in my Post Office telecoms days I heard of a strowger exchange where a new cleaning contractor decided to save money by using their standard silicone floor polish rather than the PO specified beeswax.  The silicone oil crept all over the equipment – all those lovely relays and uniselectors with arcing contacts.  Result, one exchange out of service.

[Trevor GaleParticipant @trevorgale]

Nicholas Farr: You wrote: “P.S. this machine doesn’t record or play DVD’s as the video laser has failed and replacements are no longer available, but it will still play music CD’s, and has Scart input and output sockets, which is handy for connecting up other equipment, as and when needed.”

 

I am surprised that you think the laser has failed – for if it cannot play DVD’s but still plays music CD’s then the laser must still be working – both media are optical. That it will not record DVD’s could be due to a slightly worn-out laser, but it is far more likely that the lens is out of alignment, perhaps too far from the disc surface and therefore out of focus – a CD has a track density of 1.6uM (micrometres, I don’t have the ‘mu’ symbol!) whilst a DVD has a density of 0.74uM, so a DVD requires the laser assembly to be in good focus.

I would try cleaning the laser head assembly arm and the ‘rest; that it runs on and see if that improves the focus issue.

[Author]

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