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-   -   Westclox EM21 electric clock (https://www.vintage-radio.net/forum/showthread.php?t=182837)

Aristomatic 15th Aug 2021 9:38 am

Westclox EM21 electric clock
 
Hi everyone.

1st post be kind..!

Looking to find assistance to either repair or source replacement unit or

maybe helpful direction to another forum if members advise?


EM 21 Model, made in Scotland, looks to be Westclox? but not branded

It's in a lightup sign, maybe 60's or 70's, has a second hand.

Was working but occasionally the second hand on start up went backwards

but switching off and on again seemed to cure that. I've been very poorly so

not switched on for over a year and now dead! The fluorescent tube still works

and live feed to clock comes off same terminal. Both wires still secured in motor,

eg not disconnected.

Thankyou In advance

McMurdo 16th Aug 2021 9:44 pm

Re: Westclox EM21 electric clock
 
Maybe just needs a clean and lube? If it used to go backwards sometimes, that sounds like the one-way ratchet was sticking or worn, synchronous clock motor designs can often start up forwards or backwards as they choose and are prevented from continuing backwards by a ratchet.
If you get a reading through the winding then I suspect its little holiday has allowed it to go a bit stiff.

Sounds an interesting piece, do you have any pictures? Google shows there was a westclox mantle clock on ebay which the seller described as being marked 'EM21'. Our local newsagent used to have an electric clock in the 70's built into an art deco illuminated Benson & Hedges sign.

rambo1152 16th Aug 2021 10:45 pm

Re: Westclox EM21 electric clock
 
1 Attachment(s)
Electrically your clock movement couldn't be simpler, its just a coil of wire across the mains.
So there are two possibilities, either something mechanically stuck, which is probably fixable by cleaning and re-lubricating, or the coil, the motor winding, has gone open circuit, and that could be very difficult to fix.

Do you have a multi-meter?

If so, with the clock unplugged, can you disconnect one side of the motor and measure its resistance ?
I just tried it on a similar clock and got 8 kilo Ohms. See if you get a reading in that ball-park.

If it's difficult to isolate the motor, as long as you remove the florescent tube, you should be able to measure its resistance between the live and neutral pins of the plug.



Amusing postscript.
I tried measuring one of my own clocks at the plug.

I rewired it some time ago with a modern plug and modern twisted pair double insulated flex salvaged from some blown incandescent xmas lights, as the flex looks retro.

Attachment 239516

My meter gave a reading of infinity, open circuit, yet the clock works perfectly.

Anyone care to guess why this was?

mark_in_manc 16th Aug 2021 11:04 pm

Re: Westclox EM21 electric clock
 
Errr - you wired it between L and E, and were testing between L and N pins? (If we knew each other, that would be funny; as it is, it sounds like an insult - sorry :) )

rambo1152 17th Aug 2021 2:26 am

Re: Westclox EM21 electric clock
 
Well by my calculation the clock draws about 30mA so I would expect the house would be plunged into darkness if I had done that.

mark_in_manc 17th Aug 2021 7:19 am

Re: Westclox EM21 electric clock
 
Aaah - there, I'm the one deserving the insult (I'm still on Wylex fuses - I'd blame it on living in the deprived inner-city, but allegedly it's posh in Whalley Range these days) :)

I don't have a better guess. I think that's a Metamec movement - I like them, I had some success fixing a couple where the fault was mechanical.

Mike Phelan 17th Aug 2021 7:34 am

Re: Westclox EM21 electric clock
 
Hi there (?)

If the coil is O/C there are a few folk on here who can rewind it. Please don't convert it to low voltage!

It probably just needs a dismantle, clean and lubrication. Give us some pictures and we'll see what it actually is.

Brigham 17th Aug 2021 8:34 am

Re: Westclox EM21 electric clock
 
Quote:

Originally Posted by rambo1152 (Post 1398897)

My meter gave a reading of infinity, open circuit, yet the clock works perfectly.

Anyone care to guess why this was?

Your AVO battery is flat?

Rubberfingers 17th Aug 2021 9:19 am

Re: Westclox EM21 electric clock
 
Quote:

Originally Posted by rambo1152 (Post 1398897)

My meter gave a reading of infinity, open circuit, yet the clock works perfectly.

Anyone care to guess why this was?

If it's not an oxidized contact somewhere (plug pins or fuse clips, or even a faulty plug fuse (the end caps are pressed on and in some designs of fuse, make contact with another disc connected to the fuse element), then I would suggest that the coil has a tiny break in it somewhere, and the mains can break down the carbonised gap but the low voltage from the meter can't.

rambo1152 17th Aug 2021 11:42 am

Re: Westclox EM21 electric clock
 
1 Attachment(s)
Quote:

Originally Posted by Brigham (Post 1398956)
Your AVO battery is flat?

Actually if I was using a moving coil multimeter rather than a digital one on Ohms, I would have got a reading and a clue.

Quote:

Originally Posted by Rubberfingers (Post 1398971)
If it's not an oxidized contact somewhere (plug pins or fuse clips, or even a faulty plug fuse (the end caps are pressed on and in some designs of fuse, make contact with another disc connected to the fuse element), then I would suggest that the coil has a tiny break in it somewhere, and the mains can break down the carbonised gap but the low voltage from the meter can't.

The oxidised contact is sort of right in a way :D
It's more a matter of quantum depletion layers though

Here's the reason

Attachment 239527

I had forgotten about that diode!

Remember I said the cable and plug were from an old mains series string of fairy-lights?

We all know that these have a failure mode where as each bulb fails and shorts itself out the string take more and more current until the fuse-bulb pops (if there is one). Plus the string always looks too bright and over run to me, even when all the bulbs are intact.

Well a long time ago I started to put a series diode in the plugs of these when new.

It was a bit of a long shot that anyone would have guessed exactly what I had done and why with the clues I gave, but stranger things have happened on this forum.

So back to the clock. Should I be surprised that the clock starts up and runs fine with the diode?
Is it kinder to the motor to leave it in or should I remove it?

Aristomatic 18th Aug 2021 1:29 pm

Re: Westclox EM21 electric clock
 
1 Attachment(s)
Well only just found my thread.

Saw x9 replies thought great. Alas however! Only most about another posters wiring LOL!

I got clock off the sign & placed some sewing machine oil in couple of places, away from any wiring. Plugged in and the second hand went around, smoothly in some areas but less smooth in others, probably as noticed some damage to cogs in places. I've decided to replace with another same or similar model electric unit from most ugliest Westclox clock that has silent running and keeps good time. Hoping some horrific looking mantle clock that will get no other bids!

Thanks for input so far, it's much appreciated.

McMurdo 19th Aug 2021 12:09 pm

Re: Westclox EM21 electric clock
 
I like it, these days you don't see many signs that command you to do something like 'Drink Pepsi' or 'Shop at Harrods' or 'Make Your Next Car a Mercury'. All part of the charm!


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