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Dead NeXTstation floppy drive
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wa2flq



Joined: 18 Dec 2008
Posts: 30
Location: Chicagoland

PostPosted: Mon May 16, 2016 5:34 am    Post subject: Reply with quote

bobo68 wrote:
paolo.bertolo wrote:

Quote:
Its a Crystal Oscillator.

I also think it's an oscillator: however, all I could figure out is that it's 3 pin component. Not much. Googling the name led to no match.


wa2flq is right, it is most probably a crystal oscillator. Found a similar piece described as part of another Sony floppy drive: http://matthieu.benoit.free.fr/101.htm. Also the symbol underneath the component seems to designate an oscillator.


If the crystal has been damaged, that would certainly kill the unit. Since its a three pin device, ignore my earlier comment about load, its not just a crystal but a integrated oscillator. The inputs are +5 and gnd, and output is the clock. From the photo's I suspect it will the middle pin and you should be able to put a scope or counter on the pin.
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paolo.bertolo



Joined: 24 Sep 2015
Posts: 57
Location: St Gallen, Switzerland

PostPosted: Mon May 16, 2016 11:22 am    Post subject: Reply with quote

Quote:
Found a similar piece described as part of another Sony floppy drive

Very interesting link, thanks.
However, even though the naming of the "transistor" is quite similar (N 5 G and N 5 M here respectively), I must confess I have doubts it's about a transistor we're speaking about. I have de-soldered it and there are just 2 pins (should be 3 of them, right?).

https://db.tt/u6nSGg9L

Besides, even on the A side, underneath the component (PS01) there's a symbol looking like a circuit breaker.

https://db.tt/e3fBtUSo

Anyhow, either way, with this component not in place, the voltage readings are not changing, so either it's neutral or, since it's damaged, in place or not makes no difference.

Quote:
The inputs are +5 and gnd, and output is the clock. From the photo's I suspect it will the middle pin and you should be able to put a scope or counter on the pin.


There are no +5V, that's why I suspect the damage is before the oscillator.
In those places where I should read 5 V, in fact I see some 3 V only.

https://db.tt/JBtXvKRA

Thanks to All who are contributing to this discussion.

(By the way, how the hell can I include the author in the quoted text?)
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bobo68



Joined: 03 Jun 2015
Posts: 194
Location: Germany

PostPosted: Mon May 16, 2016 12:45 pm    Post subject: Reply with quote

paolo.bertolo wrote:

However, even though the naming of the "transistor" is quite similar (N 5 G and N 5 M here respectively), I must confess I have doubts it's about a transistor we're speaking about. I have de-soldered it and there are just 2 pins (should be 3 of them, right?).

Maybe I'm too simplistic here but:
semiconductor with 3 legs -> transistor
semiconductor with 2 legs -> diode

Theory 1:
It is a current limiting diode in an unusual packaging. If you are brave you just short the contacts on the pcb and see what happens... Of course this could end in smoke and destruction.

Theory 2:
The wave symbol stands for AC and the diode is a simple rectifier. Do you measure AC across the contacts?

P.S. to put a name in the quote use quote="<name>". The blog software should do this automatically.
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wa2flq



Joined: 18 Dec 2008
Posts: 30
Location: Chicagoland

PostPosted: Mon May 16, 2016 1:09 pm    Post subject: Reply with quote

bobo68 wrote:
paolo.bertolo wrote:

However, even though the naming of the "transistor" is quite similar (N 5 G and N 5 M here respectively), I must confess I have doubts it's about a transistor we're speaking about. I have de-soldered it and there are just 2 pins (should be 3 of them, right?).

Maybe I'm too simplistic here but:
semiconductor with 3 legs -> transistor
semiconductor with 2 legs -> diode

Theory 1:
It is a current limiting diode in an unusual packaging. If you are brave you just short the contacts on the pcb and see what happens... Of course this could end in smoke and destruction.

Theory 2:
The wave symbol stands for AC and the diode is a simple rectifier. Do you measure AC across the contacts?



I would splice in a quick blow fuse, say 1/8 amp in place of the N5G device. Is the N5G open (check it with diode test on a VOM)? Do not just short it. I cannot find a similar device in that form factor. The symbol for Fuse and AC are similar, but I would never expect to see the AC symbol across the component (on both sides of the PCB!).

For the "Crystal Oscillator", I also cannot find similar 3 pin package for this. The pcb symbol is typical for crystal, but it looking around it is possible that it may be a ceramic filter. My background in floppy signal recovery is practically nil, so I cannot speculate if this would be a reasonable component for this design. See http://www.radio-electronics.com/info/rf-technology-design/receiver-selectivity/ceramic-if-rf-bandpass-filters.php The symbols are usually different for a ceramic filter.
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paolo.bertolo



Joined: 24 Sep 2015
Posts: 57
Location: St Gallen, Switzerland

PostPosted: Mon May 16, 2016 1:21 pm    Post subject: Reply with quote

Thanks guys for the prompt feedback, I will try to check everything according to your instructions over the next week end, I will keep you posted!
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hyoenmadan



Joined: 17 Jun 2016
Posts: 2

PostPosted: Fri Jun 17, 2016 11:22 am    Post subject: Reply with quote

PS01 is an "Integrated Circuit Protector" device (probably a sort of fuse, but who knows). N code stands for the TO92 packaged type and the 5 code says it is 250mA rated. M probably is the manufacturer code, and it actually has no meaning in device functionality.

NTE distributes these as NTE15019E. Also you can find them as generics using "N5 TO92 ICP" keywords at google.

Not every thing that comes as TO92 package is actually transistor, or even a semiconductor.


Last edited by hyoenmadan on Fri Jun 17, 2016 8:14 pm; edited 1 time in total
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bobo68



Joined: 03 Jun 2015
Posts: 194
Location: Germany

PostPosted: Fri Jun 17, 2016 11:34 am    Post subject: Reply with quote

It's good when somebody just knows stuff. Smile Thanks for the clarification.
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