A transistor has two PN junctions, by shorted do you mean that the diode function of your meter shows 0V forward voltage? Or something else?
Swissonic DA24 looking for operation manual or schematic, auto mute and noise
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A transistor has two PN junctions, by shorted do you mean that the diode function of your meter shows 0V forward voltage? Or something else?
For me short means direct connection, so it works like a single diode. If This would be BJT, then Base and Emitter are connected toghter.
This is common fault on burned BJT.
If this would be a diode not transistor, then one of bottom pins would be not connected to anything and manufacturer would mark it D symbol, as a diode, like all the rest of the diodes inside the circuit.
Besides that this single part have exhangable soldering points for SMD and THT component, both marked as Q as mentioned before.
If this would be a SO-23 diode for SMT then THT equivalent rather would be just two point soldering part as for THT diode - instead is three terminal transistor equivalent.
NPN here wouldn't rather have sense, but maybe i will try and check what happens.
So the diode is definately excluded, expecting rather FET.
Did i explained this understandable?
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But you said you used diode function of your meter, and base to emitter forms a PN diode junction. You should expect to see a connection from base to emitter using diode function of your meter, with the forward voltage approximately 0.5V-0.7V depending on specific type of transistor. Using the resistance function the meter usually will use a small voltage, so show no connection between base and emitter. If the base-emitter junction is truly shorted you should be able to measure a finite resistance connection even with the resistance function, or if using the diode function the forward voltage should be very low and the same when measuring base to emitter or emitter to base.
Overall, thank you for help. Sorry, my english is rather autistic and i have problem clearly explain simple things. Yes, my multimeter as many others (not every) in diode function mode have a "beeper", which is able to show direct connection (i call it a "short"). So, to be clear (i hope), checking Base and Emitter it give the constant beeping sound, so it shows that this part of the circuit is shorted. Base and Emitter works as the same node.
Between these nodes and Colector there's reading as for PNP transitor.
B/E red probe, C black probe - shows nothing.
B/E black probe, C red probe - shows reading
Between these nodes and Colector there's reading as for PNP transitor.
B/E red probe, C black probe - shows nothing.
B/E black probe, C red probe - shows reading
Hi, Alan.
I have a spare Swissonic DA24 Mk2, sporadically used about 20 years ago in my home lab/studio. It was put in storage in its original box when I bought a RME ADI-8 AE. I am now selling the Swissonic if you are interested. Cheers from Norway.
I have a spare Swissonic DA24 Mk2, sporadically used about 20 years ago in my home lab/studio. It was put in storage in its original box when I bought a RME ADI-8 AE. I am now selling the Swissonic if you are interested. Cheers from Norway.
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Thanks to user @shot we have schematic for analog section!!!!
https://groupdiy.com/attachments/swissonicda24-jpg.120209/
Does anyone knows how to disable auto mute?
https://groupdiy.com/attachments/swissonicda24-jpg.120209/
Does anyone knows how to disable auto mute?
OK
Lift the automute pin of the DAC chips? And/or tie them to the 5v rail supplying the chips through a 10k (per chip)?
I think i did it when overall i was working on it and it didn't worked - but to be honest i will have to try again - sorry, don't remember.
For application notes:
AUTO-MUTE - Automatic Mute on Zero-Data, PIN 11.
When Auto-Mute is low the analog outputs are muted following 8192 consecutive LRCK
cycles of static 0 or 1 data. Mute is canceled with the return of non-static input data.
Disconnecting it from digital ground rather will not bring here static 1?!?
Mute Functions
The CS4390 includes an auto-mute function which
will initiate a mute if 8192 consecutive 0’s or 1’s are
input on both the Left and Right channels. The
mute will be released when non-static input data is
applied to the DAC. The auto-mute function is useful for applications, such as compact disk players,
where the idle channel noise must be minimized.
This feature is active only if the AUTO_MUTE pin
is low and is independent of the status of MUTE_L
and MUTE_R. Either channel can also be muted
instantaneously with the MUTE_L or MUTE_R
So i need to test it again to say something more...
From the analog side, i need to try run analog section on +/-15 or even +/-18V and see will this bring noise down in this unit. Limitation of 18V is for SSM2142, OP275 can work up to 22V. Original +/-12V looks little weak, regulators are getting hot quickly, and there's few good volts drop in regulators.
Disconnecting the auto-mute signal (and pulling it high) will NOT introduce "static 1" onto the SERIAL AUDIO INPUT lines.
"8192 consecutive 0’s or 1’s are input on both the Left and Right channels"
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Will check and report!
So it works - previously i disconnected wrong pin... The dot on IC for orientation was the residue of flux...
Auto-Mute modification (disable):
Pin 11 need to be disconnected from ground. Much easier is just cut small trace than desolder and bend the leg.
Left only small noise reduction, it'snot so bad after all modifications but i think it could be still lower
Auto-Mute modification (disable):
Pin 11 need to be disconnected from ground. Much easier is just cut small trace than desolder and bend the leg.
Left only small noise reduction, it'snot so bad after all modifications but i think it could be still lower
On chips with pins on two sides, pin 1 is usually on the lower left, when the chip markings are the right way up (not upside down).
