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Naim NAT 01 zenner diode identification

Gervais Cote

Predator
Gents,

I am rebuilding a Naim NAT 01 tuner and I would like to double check with you to make sure I replace a faulty zenner diode with the proper one.

The zenner diode is made of clear glass, orange inside, 4 mm long and I can read this on it with a magnifying glass :

ON
BZX
56C

So, according to me, this would be an On Semiconductor, series BZX, 56 volts, does that make sense ?

Also, should I replace with an On Semiconductor or you would suggest another brand ?

And by the way, what on line distributor would you recommend as well ?

Thanks in advance.
 
Okay,

I took a bigger magnifying glass and here is what I see now from top to bottom when I rotate the diode :

BZX
55C
16

And that makes more sense as a series 55 seems to be more standard and 16 volts looks like a good value in an tuner, am I right ?
 
56C is the series, there should be another two digit number or digit "V" digit for less than 10V
Zener has one "N"
 
I have 2x nat 01s here, let me know where its situated and I will double check it for you.
 
Why does it need rebuilding? It's a fully analogue tuner and will require a lot of work re-aligning afterwards if you go about changing things.
 
I have 2x nat 01s here, let me know where its situated and I will double check it for you.

When you face the digital display, this is the first one starting form the back, on the left edge, near the antenna connection, located just beside the steel box that protects the tuner adjustable coils. It is located between two sets of two resistors.
 
Why does it need rebuilding? It's a fully analogue tuner and will require a lot of work re-aligning afterwards if you go about changing things.

I am just replacing the electrolytic and tantalum capacitors with same values. Some electrolytic were leaking so they were due to be removed. And this zener diode was also dead with over heat trace around it so it has to be changed as well.
 
I can see the bzx marking around one end of the diode and a clear number 5 at the other but am reluctant to lift or rotate them, sorry.
 
It's actually 15v now I've had a chance to review notes. It's part of the AFC/tuning range circuit.
 


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