UTC LS-140 I'm stumped!

[Twist Turner]

I'm building a transformer filled "color box" I've got 10 in there right now 600:600.........here's one that is just totally stumping me. I picked up a UTC LS140, checked it for continuity and it's good, wired it up according to the info on the UTC terminals chart and i'm getting nothing. So i checked wires to make sure there wasn't a broken wire, wires all good, measuring continuity at the xlr's same as the transformer......but no sound. I thought maybe there was the possibility it was out of phase and cancelling so i swapped leads on one end.........no sound.

Any ideas the transformer at least by continuity appears to be good yet i'm getting no sound......the other 9 in the box all work perfectly.

 

[gridcurrent]

piqued my interest,
LS-140 labeled as a hybrid repeat coil.
tested a new old stock 140;
strapped terminals 2 to 3,  terminals 6 to 7.
no issues,  flat (-0.3 dB) from 20 Hz to 20 kHz, to and from 600 ohms.

 

[emrr]

Does it look at all like it's been opened?   

 

[mjrippe]

piqued my interest,
LS-140 labeled as a hybrid repeat coil.
tested a new old stock 140;
strapped terminals 2 to 3,  terminals 6 to 7.
no issues,  flat (-0.3 dB) from 20 Hz to 20 kHz, to and from 600 ohms.

Any chance for DCR or inductance readings?

 

[Twist Turner]

reading with the ohm meter was around 50.5- 51 if i remember correctly that is with 2/3 and and 6/7 jumpered.

Not only didn't it look opened, there it didn't appear to have ever been soldered  before either

 

[moamps]

Maybe one coil is unintentionally internally swapped/out of phase. Apply signal to 1 and 3 and measure signals at all remaining three coils.

 

[rackmonkey]

What ever happened with this? Did you get it figured out?

 

[Twist Turner]

What ever happened with this? Did you get it figured out?

No not working.  What is strange is both 1/2's of the input windings work but when jumpered at pins 2/3 and connecting 1 and 5(there is no 4) when measuring continuity it shows i am getting continuity between the 2 combined but i get no output.......

 

[gridcurrent]

the ladies that wound UTC coils sometimes made mistakes.  maybe the polarities are reversed.

 

[Twist Turner]

the ladies that wound UTC coils sometimes made mistakes.  maybe the polarities are reversed.

I tried reversing polarity on the output and got nothing, maybe i should try the input

 

[emrr]

It'll be interesting if a coil has flipped polarity.  I've yet to see one that canceled well enough to be effectively silent, there's usually enough of something to sound like a failure. 

 

[rackmonkey]

It’s a weird one.  I’m pulling a couple out to fiddle with tonight to see if I can come up with any ideas for comparisons, other than the obvious.

I do recall that the 140 is a weird beast. Very sensitive to source and especially load Z for a 1+1:1+1 transformer. Really big response variations IIRC. But it’s been a while since I messed with one.

I think I remember CJ tearing one down and commenting on how unusual the winding structure was, but I can’t find any pictures or posts on a quick search.

 

[emrr]

I think I remember CJ tearing one down and commenting on how unusual the winding structure was, but I can’t find any pictures or posts on a quick search.

I saved this in Dec 2009, don't know where the thread is:

this thing turned out to be pretty weird,


ok, so it Is another 31UI, wtf, over? plus, they forgot one of the coils, i am going to call UTC,  

this is a Hybrid transformer,


this is something i have not seen since i worked at Aydin Energy building transformers,  folded shields:


so that center winding in this pri-sec-pri rig is buried under two copper shields whose ends are tucked,

this keeps cross talk down to about -92 db , catalog spec,


more weirdness, bi fi windings, this is the splice from the outer pri to the inner pri,>

heavy cardboard in between pri-sec, another weird tweak. usually you want  copper in the window,


how do they wind these things? slowly.. we use to put a piece of mono fish line in between, better C,


 there is a piece of copper in there, inside the yellow mylar, it gets wrapped around the leads,





first layer.  all thw windings are bi-fi,  200t - 400f- 200t, so twice that = 800 turns , pri, 800 sec.



 

[moamps]

....(there is no 4) ....

Is it LS-140 at all if there is no pin 4? On Pin 5 should be wired one secondary coil. Could you post a picture of it?

 

[emrr]

Is it LS-140 at all if there is no pin 4? On Pin 5 should be wired one secondary coil. Could you post a picture of it?

Mmmm.  True. 

 

[PRR]

I saved this in Dec 2009, don't know where the thread is:

https://groupdiy.com/index.php?topic=35773.msg439639#msg439639

All images rotted away.

 

[CJ]

it is supposed to kill all the sound, that is what hybrids do.

only the operator is  allowed to be heard.

"i'd like to make a collect call to US Bail Bonds in Tijuana"

'one moment please..."

 

[CJ]

maybe this is not a hybrid, we did hack a hybrid, was that the LS-68?

this one looks normal, i have to clean up the print,

all my transformer prints are in the Magnetics  forum under their brand name.

here is the UTC section.

https://groupdiy.com/index.php?topic=74166.0

 

[CJ]

me wrong. again.  it is the 141 that is the hybrid>

 

[Twist Turner]

I've been busy with some other projects the last week. i'll dig into this transformer later further later in the week.