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Nak BX-300 need transformer

Debassige

Debassige

Well-Known Member
I need to replace the transformer in a Nak BX-300 I've just aquired. I've downloaded the service manual but have been unable to determine the output of the secondary windings. It is the primary that is shot. Finding a donor BX-300 would be great but it might be just as easy finding a new (generic) transformer (possibly a toroidal).

Any help would be greatly appreciated. This is my first NAK deck and is in (cosmetically at least) nearly mint condition so putting a few bucks into it is definetly worth it.
 
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the transformer is highly likely to have a temp fuse built in .you have nothing to lose but your time by carefully removing the covering that goes over the windings to find the fuse .if its open you could measure the windings with your meter on ohms and if ok replace the fuse and test the transformer . i have done this a few times with good results ..
 
Thanks. Have started to dig into the transformer and no obvious sign of the fuse, but I will keep digging.

The deck worked fine when I first brought it home but the transformer got extremely hot and then just died. I have continuity in the secondary windings but nothing in the primary (probably because of the fuse). I'm guessing even if I did find and repalce/repair the fuse, there must be a something that caused it to blow in the first place.

I'll keep working on the transformer but am fairly sure I'll need to replace it or will end up needing to replace it once I'm done with it :D
 
dismantled (destroyed) tranformer and no sign of fuse, it was fun but now I need a new transformer.

Does anyone know the secondary voltage for the transformer on a BX-300. I've gone over the service manual and think it might be 12V, does this sound right (I've downloaded the manual from Hifiengine if anyone would like to take a look) :scratch2:
 
tried looking but my eyes are hurting now ..looks like a plus and minus supply .so you have black and 2 yellow wires from secondary .
if it got as hot as you say its sounds toasted anyway .maybe the thermal fuse is buried under the windings on your one .
 
The odds are that some of the lesser BX models share the same PT. You should be able to find one of those quite inexpensively which you could sacrifice.
 
I've checked out a number of the service manuals for some of the lesser models (some but not all yet) and they all have different part numbers.
 
The BX-300 transformer has a simple secondary with two AC outputs and GND. I've seen the Service man. and have found nothing about the AC voltage that outputs the transformer. HOwever, the main power supply circuit is highly regulated and I guess that could be driven with a +/- 20Volts or even 16 Volts, It regulates down to 12 Volts. THere are three total circuits. the main circuit, the circuit that detects the power shutdown to quickly stop the deck with the capacitor energy left, and the led meter circuit.

If desesperate, You could try with a low voltage three (AC,AC, GND) outputs transformer.

Check or replace the fuses, and try to check for continuity in diodes / capacitors
 
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