NTP 179-400

Hi!

My NTP 179-400 is distorting. The problem seems to be in the VCA and more exactly in the Bipolar Transistor called IT126. It´s seems to be VERY hard to find!

Any ideas?

Please, i´m getting frustrated!!!

try them,
they might be expensive but they usually get pretty much any component you need.

http://www.mark5.co.uk/

Best,
Mattia.

Thanks!

I sent them an enquiry, let´s hope it works out!

The part wasn´t found in their stock list that i tried but let´s hope they have stuff that isn´t in the list...

IT126, dual NPN
VCEO=60V
hfe=200
IC(max)=100mA
Cobo(max)=3pF
ICBO(max)=100pA

audiox said:

IT126, dual NPN
VCEO=60V
hfe=200
IC(max)=100mA
Cobo(max)=3pF
ICBO(max)=100pA

Click to expand...

Sorry to be such a newbie but do you mean that there is some other trannie with similar values to use and that it wouldn´t change the sound of the VCA?

I found a note in an old service manual that MP312 could be used as a replacement without tuning the circuit (I am not sure if that piece of information is accurate or not). I guess the IT126 was hard to get even 20 years ago...

Why do you think that the IT126 is the faulty part?

audiox said:

I found a note in an old service manual that MP312 could be used as a replacement without tuning the circuit (I am not sure if that piece of information is accurate or not). I guess the IT126 was hard to get even 20 years ago...

Why do you think that the IT126 is the faulty part?

Click to expand...

Great info!

We have two cards so we took a replacement from the other temporarily...so it was the IT126.

Do you happen to still have that service manual?

telefunk said:

Do you happen to still have that service manual?

Click to expand...

I don't have a scanner but you can find the manual online with a little search.

Have you re-engineered the M510 module? One of my colleague did that for practically all NTP modules but I don't have the schematics anymore. Posting a schematic would be the easiest way to get good advice from the forum members (and a great contribution to others working with the same problem).

I know that M510 modules have been succesfully repaired in broadcast use with more or less standard parts. If you don't find the exact type you could try something "close enough".

Hi,

  i have manual pdf. Send me your email. My manual doesn't have vca details. My units don't have M510, but a later unit using DBX 2151's. I'd love to see how the M510 sounds in comparison. My units sound amazing btw!


    Using 'em every day . . .


    ANdyP

strangeandbouncy said:

Hi,

  i have manual pdf. Send me your email. My manual doesn't have vca details. My units don't have M510, but a later unit using DBX 2151's. I'd love to see how the M510 sounds in comparison. My units sound amazing btw!


    Using 'em every day . . .


    ANdyP

Click to expand...

Hi!
I pm´d it to you!

At least the other cards sound fantastic! The other is completely distorted ;-(

The M312 seems quite rare also...is there other types that are close enough...

"fraid I can't help you there . . . .


    I am sure that someone here can.



  ANdyP

Thanks for the manual Andy! It helps!

Anyone with M510 schematic? Since, for some strange reason, it´s not written in the 179-400 schematic...

Yeah,



  wot da \Funk sed . . . . anyone got an M510 schemo?


      'Fess up, my brethrin . . .


      ManyTHANkses,



        ANdyP

telefunk said:

Anyone with M510 schematic?

Click to expand...

your M510 module + half an hour of time = schematic

audiox said:

telefunk said:

Anyone with M510 schematic?

Click to expand...

your M510 module + half an hour of time = schematic

Click to expand...

true. It´s double sided pcb and super packed, so it´s bit challenging but i can try.

Audiox,


  I would LOVE to lend you my M510, but I don't have one! Mine are the later DBX vca version.



    Kindest regards,


      ANdyP

strangeandbouncy said:

Hi,

  i have manual pdf. Send me your email. My manual doesn't have vca details. My units don't have M510, but a later unit using DBX 2151's. I'd love to see how the M510 sounds in comparison. My units sound amazing btw!


    Using 'em every day . . .


    ANdyP

Click to expand...

Andyp, Could you send me that info to my please??....my e-mail is:

[email protected]

Thanks anticipated!
Opacheco

if you're  interested in a spare , PM me.