Question Harman kardon citation 16 variable resistor

[Badula]

Hi all. I need some help.
I have recapped art Citation 16 amp. Unfortunately it suffers a common problems on these amps it seems. The variable resistors are finished.
Is there someone who knows what kind I should replace them with? A link perhaps?
I know the 500ohm one. But what does (IM ohm) mean?
Thanks

 

[Din5]

One Mega Ohm / 1 million Ohms (assiming the I is the digit 1 )

 

[Badula]

thank you !
Any kind? Or any brand?

 

[Gray]

I know the 500ohm one.

Are you sure that one isn't 500k ohms (500,000 ohms)?

Do you mean variable resistors on the PCB (known as presets) rather than rotary controls (like volume/ tone controls?

Maybe post a zoomed-in photo.

 

[Badula]

Are you sure that one isn't 500k ohms (500,000 ohms)?

Do you mean variable resistors on the PCB (known as presets) rather than rotary controls (like volume/ tone controls?

The variable resistors on the PCB board. One is for the idle current. And the other for Output “idle”
As I can se in the service manual the is no K in the 500. I will attach a file

 

[Gray]

Any kind? Or any brand?

Provided that they're physically the same (the 3 pin / leg spacing / horizontal or vertical type).
Whatever types you're replacing, go for the enclosed, rather than the open (skeletal) types.

Search 'preset resistor' and you'll see a few.

Use an accurate meter to set them 👍

 

[Badula]

Provided that they're physically the same (the 3 pin / leg spacing / horizontal or vertical type).
Whatever types you're replacing, go for the enclosed, rather than the open (skeletal) types.

Search 'preset resistor' and you'll see a few.

Use an accurate meter to set them 👍

Thank you very much. As one replied and questioned 500ohms. Is this a correct value ? There is no K in the 500 ?

 

[Gray]

Thank you very much. As one replied and questioned 500ohms. Is this a correct value ? There is no K in the 500 ?

Yes, assuming the manual is correct, then VR2 is 500 ohms.

 

[Badula]

Yes, assuming the manual is correct, then VR2 is 500 ohms.

Nice! Thank you !🙏

 

[Badula]

Yes, assuming the manual is correct, then VR2 is 500 ohms.

Hi again!
Problems… got the new variable resistors…
There is 30 volt!!! On channel A (blown transistor?!) 🤬 and Channel B “kinda works” but as hotter it gets on channel B the idle current lowers!?! Bad emitter resistors ?? It goes even to Minus ➖ as hotter it gets ? Ahh son of a *****… 😤😭

 

[Badula]

It seems also that the PA/UA739pc IC are spooky to… read on many threads that these Opamps are bad… any one out there who has knowledge about these ones?

 

[Gray]

Hi again!
Problems… got the new variable resistors…
There is 30 volt!!! On channel A (blown transistor?!) 🤬 and Channel B “kinda works” but as hotter it gets on channel B the idle current lowers!?! Bad emitter resistors ?? It goes even to Minus ➖ as hotter it gets ? Ahh son of a *****… 😤😭

It seems also that the PA/UA739pc IC are spooky to… read on many threads that these Opamps are bad… any one out there who has knowledge about these ones?

☹️
Time to decide if / how much you're prepared to pay for a professional repair.
Get reliable estimate(s) first 👍

 

[Badula]

Checking all emitter resistors and transistor right now. 😤😭