LO1166 issue in 1272

[Golgoth]

Hi,

I am having an issue with an LO1166 transformer I am installing in a 1272 module I am restoring.

The output has absolutely no bass. I tried without the zobel components, same thing.
The rest of the module is working well up until pin 1 of the LO1166, but pin 5 & 8 output no bass, the transformer basically acts as an HPF (pin 5 is louder than pin 8 if that is useful info).

What can I test/measure to make sure the transformer is okay? It was provided to me untested by a client.

Best,
G

 

[Khron]

pin 5 is louder than pin 8 if that is useful info

In relation to what, exactly?

 

[Golgoth]

In relation to what, exactly?

Pin V on the back connector

 

[Golgoth]

I wonder what you think about it Ian @ruffrecords

 

[ruffrecords]

How did you set the quiescent current in the 2N3055? Sounds like the core might be saturating.

Cheers

Ian

 

[Golgoth]

How did you set the quiescent current in the 2N3055? Sounds like the core might be saturating.

Cheers

Ian

Thanks for chiming in Ian, I provided a 1K sinewave at +20dbu and set RV1 for 4.7V across R7

 

[ruffrecords]

Thanks for chiming in Ian, I provided a 1K sinewave at +20dbu and set RV1 for 4.7V across R7

That looks a little on the high side to me. Try setting it to 3.3V.

Cheers

Ian

 

[radardoug]

Your wiring is probably wrong, and you dont have both ends of the primary or secondary wired correctly.

 

[Golgoth]

That looks a little on the high side to me. Try setting it to 3.3V.

Cheers

Ian

Will try and report back!

 

[Golgoth]

Your wiring is probably wrong, and you dont have both ends of the primary or secondary wired correctly.

Pin 2 & 4 linked
Pin 6 & 7 linked
Pin 1 to BA283 card Pin B
Pin 3 to BA283 card Pin M
Pin 8 to back connector Pin R
Pin 5 to back connector Pin T

 

[ruffrecords]

Pin 2 & 4 linked
Pin 6 & 7 linked
Pin 1 to BA283 card Pin B
Pin 3 to BA283 card Pin M
Pin 8 to back connector Pin R
Pin 5 to back connector Pin T

And you have J linked to A?

Cheers

Ian

 

[CJ]

Is it an original? Check continuity.

 

[Golgoth]

And you have J linked to A?

Cheers

Ian

Absolutely, A-J-V are linked

 

[Golgoth]

Is it an original? Check continuity.

Hi CJ, continuity is fine per the transformer's datasheet. It is an original Marinair.

 

[Golgoth]

That looks a little on the high side to me. Try setting it to 3.3V.

Cheers

Ian

No improvement at 3.3V unfortunately