Phoenix Gold ZX475

[caraudioguy2100]

I have a shorted C2389 transistor used as a pre driver in the output stage .

Is there a good sub for this ? Or a transistor I can use for testing ?

 

[Perry Babin]

Virtually any transistor of the correct polarity and sufficient voltage should work for testing.

It appears to be obsolete. What are the space constraints?

 

[caraudioguy2100]

I have plenty of space to fit almost any transistor in there

 

[Perry Babin]

The KSC2690A and KSC1220A are way overkill but are generally good audio driver replacements.

Someone on the phoenixphorum may have a verified suitable replacement.

 

[caraudioguy2100]

Replaced the drivers and went through the channel but still have a problem somewhere .

I can’t get the less to light up in that channel and I know they work and the channel has no output

 

[Perry Babin]

Are the LEDs in working condition?

What is the voltage across them?

 

[caraudioguy2100]

The voltage across them is 0.00 volts

The leds in the other channels measure 36 volts across them

 

[Perry Babin]

Did you measure the voltage with one meter probe on each terminal of the LED?

 

[caraudioguy2100]

Yes black probe on 1 side of led and red probe on the other side of the led .

And I took an led out and tested it and the led is good

 

[Perry Babin]

Check all of the flameproof resistors. They are the resistors with the rough ceramic coating.

 

[caraudioguy2100]

All the resistors check good .

There is a C1567 transistor that controls the leds and the rail for that channel and it’s not putting and voltage out .

Do you happen to know of a good replacement since these are obsolete

 

[Perry Babin]

What's the DC voltage on each terminal of the transistor?

The readings on the LEDs doesn't seem right. I would expect only about 2v across the lit LED. both 36v and 0v are unexpected.

 

[caraudioguy2100]

Let me check a few more things and I will get back to you with the voltages on the transistor

 

[caraudioguy2100]

Wondering does the 2SC3248 have the same pin out as the C2690?

From the data sheets I found it appears they do but someone said they are flipped backwards ?

 

[caraudioguy2100]

Never mind had the part number wrong