Jawari Transformer question

[CodeMonk]

I went to build a Jawari the other day.
I started without really looking at the required transformer.
The Radio Shack one is a not go.

Around these parts, I'm known as the guy that will take busted electronics off your hands.
I have a bunch of old TV's, stereo's etc.

Many of them have small transformers about the size of the Radio Shack one, which I am guessing is also the size of the one required by the Jawari.
How would I go about testing these to see if any are compatible with the 42TM018?
Would it just be as simple as measuring the resistance of the windings?

[Paul Marossy]

Many of them have small transformers about the size of the Radio Shack one, which I am guessing is also the size of the one required by the Jawari.
How would I go about testing these to see if any are compatible with the 42TM018?
Would it just be as simple as measuring the resistance of the windings?

RadioShack doesn't sell tranformer with those specs. Physical size of the transformer is not a reliable indicator of anything. A 10K:10K transformer is not a common size from what I can tell, you're not likely to find one in some old electronic device. It's a lot easier to just buy a few from Mouser, they're not expensive at all.

[CodeMonk]

Many of them have small transformers about the size of the Radio Shack one, which I am guessing is also the size of the one required by the Jawari.
How would I go about testing these to see if any are compatible with the 42TM018?
Would it just be as simple as measuring the resistance of the windings?

RadioShack doesn't sell tranformer with those specs. Physical size of the transformer is not a reliable indicator of anything. A 10K:10K transformer is not a common size from what I can tell, you're not likely to find one in some old electronic device. It's a lot easier to just buy a few from Mouser, they're not expensive at all.

Yeah, I know its not common and they don't cost much, and I know RS doesn't sell them.
I just want to know if there is a simple way to test the many transformers I do have in the off (and rare) chance that I may actually have one already.
I do plan on ordering a few from mouser once I pay all my bills this weekend to see how much I can allocate for those as well as other parts.

Thanks.

[Paul Marossy]

Yeah, I know its not common and they don't cost much, and I know RS doesn't sell them.
I just want to know if there is a simple way to test the many transformers I do have in the off (and rare) chance that I may actually have one already.
I do plan on ordering a few from mouser once I pay all my bills this weekend to see how much I can allocate for those as well as other parts.

Thanks.

Oh, I see. I don't think there is a way to directly measure them. I just checked the DC resistance of one of my 42TM018s (10K:10K), and they only measure 500 ohms.

[iccaros]

if you can put a known VC voltage on one side, and read the other, it will give you the stepping.. or Ratio
For 10K:10K is a one for one transformer same as a 1:1

so put 10 volts in and read the other side. if you get 10 volts its a 1:1
if you get 100 its a 1:10

if you get 1 its a 10:1
and so on.. 

use low voltage if you do not know the ratings.

[CodeMonk]

Thanks guys.
In the meantime though, I'm building a "Pocket" theremin.