MTX Thunder TA421D output inductor value?

[rhempz01]

So i have repaired a small MTX amplifier for someone. Everything is finished and working correctly. I need tk know the oem value of the output inductor. It has completely shorted, i can not get a reading. I will just go with the exact amount of wraps and wire gauge if no one has the information.
I used a test inductors of 80uH well 72uH by the time i could make it fit. The amplifier has full audio and seems to be working as intended.
Does anyone know the oem value i need to make the inductor?

 

[rhempz01]

the oem inductor.
Just a guess, im thinking around 50-60uH

 

[nigelwright7557]

Odd to find an inductor shorted as the wires are spread around a toroid.
It will be a short anyway at DC.

 

[Perry Babin]

It's very odd that you can't get any reading. Even with the two meter probes directly shorted, you're likely to get some reading.

That inductor may have a short but it looks relatively good. A shorted turn will generally leave it with hot spots. Multiple shorted turns will typically melt the insulation before the amp fails. The insulation on this one looks relatively good except for a few areas. There doesn't appear to be anything that would result in 0 inductance.

 

[rhempz01]

it had a -inductance. until i mostly unwrapped it. it melted the coating off in many spots. eventually i ended up getting a reading of 65uH. What i will do is measure out the same 16gauge of wire length and wrap it identical.

 

[jkrokenberger]

I've got one if you need it.

 

[rhempz01]

jkrokenberger i pm you.

 

[rhempz01]

Can you just measure the uH of the one you have there?

 

[rhempz01]

Same lenght of wire a 3" longer, (to compensate if need be.)
The inductance is now 125uH, which i had to unwrap over 1/2 of the old wire just to finally get a reading of 69uH.
If anyone can shed some insight on this inductor for me, it would be greatly appreciated.

 

[jkrokenberger]

I've got an inop 421D here. The supply went down and was poorly repaired at one point. I don't have an inductance tester tho.

 

[rhempz01]

you dont have a transistor tester of any kind? they will measure the inductor well enough.

 

[rhempz01]

if not do you want to sell the damaged unit?

 

[jkrokenberger]

I'll sell the unit for the cost of shipping. It will have no feet with it tho.

 

[rhempz01]

ok ill pay. private message me.

 

[rhempz01]

Ok so for the forum sake. I wrapped the inductor to 80uH. The amplifier has a strong great sound. i let it play a 40hrz test tone of my shop sub for a good 30min till the amplifier became luke warm.
So this repair is finished.

 

[rhempz01]

replaced 6 capacitors surrounding the output inductor.
rewrapped the melted output inductor to 80uH.