component from 80s unkonwn need help

[Von_Was]

i have tried to measuring it a little
 tried to figuring out what it's  and i believe its broken , but i don't know what its for sure , but i believe it might be a transformer of sort.

i believe 1 side is Primary  1.8k ohm, and the other side might be a broken 2th dary beaus i got noting that i can measure there , but i'm not sure what its , it might be an broken inductor. 

visual inspection reveals a red dot ,pretty sure its for orientation purpose.

its from a battery 6/12 /24v charger by Bima
from appers to be -86

i don't know if i ever seen one of this components before  in 20 years

and i don't know what the 4k stands for ,

P.s ignore the solder splash ,  tho that is equally confusing to me but a really easy fix.

thanks in advance //Von_Was

[edavid]

It looks like a "Vactrol", which is a type of opto-isolator or voltage controlled resistor:

https://en.wikipedia.org/wiki/Resistive_opto-isolator

[coromonadalix]

same tought, seen only once, now twice

optically controlled resistor ....    4k when lit  or 4k  at no light,  not sure about variable value ??

you have a trimpot ...

can you do a gross schematic ??

[schmitt trigger]

Most likely a Vactrol.
Unfortunately, it is of the incandescent lamp control variety, the filament could have burned out and that could be the potential reason for an open-circuit resistance measurement (if I understood your post correctly).

[Von_Was]

thank you edavid , coromonadalix ,  schmitt trigger

i will read about the Vactrol ,

i will do a full mathematics, i don't know how long ti will take , maybe a day or 3 , depending on whats going on , but i will goood enuth i hope  , started lerning Ki-cad yesterday , so i hope to be able to simulate it whit Lt Spice , when i figured that one out.  i will post results when i have tested the component , in different voltage corresponding to resistance. probebly only a few mesurements , becus maybe 5 just to get somtfing to go on (if it works) else i will tear it apart and see if i can replace the fullty part. and try to capture it on video.

[TimFox]

Specifically, the Vactrol used a photoresistor, not photodiode/transistor at the output.
In 1980, the light was almost certainly incandescent.

[Von_Was]

sorry Ben really busy , have approximately gotten time to work on this for maybe 1 hour its apparently the zen-er is dead.

have not measured the Vactrol yet , but i will get to it when i get some free time.