I was misdirected about this but will ask here if anyone has any knowledge.
Told intermittant output so assumed mechanical socket failure. USB powered
SMD digital mixer thingy. Everything about this looks suspect except the
quality of assembly which is fine for China made, 2004
Make MBOX, model MBOX
Googling the "tick" compliance number "ACN 069 650 120" produces zilch.
Under a magnifier chippery such as Fairchild, TI, Philips , but under x30
they are blotchy printed bogus mock logos of F, the Texas state and
sonogram logo of Philips
and just numbers not likes of ABnnnn type numbers.
Without pc drivers etc I doubt this one is going anywhere , but just in case
anyone knows of a stock fault producing a hash output with no hint of signal
throughput

with USB connected but no active pc. Hash on both channels of headphone
monitoring, cycling through on about 1.1 sec period. Worse when phantom is
on so maybe something with the 5 to 48V generator. Will try a few IC numbers
to check DC rails, check ESR of caps and disable unused 48V supply is about
as far as I will go.

"N_Cook" wrote in message
...
with USB connected but no active pc. Hash on both channels of headphone
monitoring, cycling through on about 1.1 sec period. Worse when phantom is
on so maybe something with the 5 to 48V generator. Will try a few IC
numbers
to check DC rails, check ESR of caps and disable unused 48V supply is
about
as far as I will go.




Isn't the Mbox Mac only?



Gareth.

"Gareth Magennis" wrote in message
...


"N_Cook" wrote in message
...
with USB connected but no active pc. Hash on both channels of headphone
monitoring, cycling through on about 1.1 sec period. Worse when phantom
is
on so maybe something with the 5 to 48V generator. Will try a few IC
numbers
to check DC rails, check ESR of caps and disable unused 48V supply is
about
as far as I will go.




Isn't the Mbox Mac only?



Gareth.




Er, scratch that, it is, but I think its a bit fussy on what it will and
won't work with.

http://archive.digidesign.com/compato/xp/69/mbox/



Gareth.

Gareth Magennis wrote in message
...


"N_Cook" wrote in message
...
with USB connected but no active pc. Hash on both channels of headphone
monitoring, cycling through on about 1.1 sec period. Worse when phantom
is
on so maybe something with the 5 to 48V generator. Will try a few IC
numbers
to check DC rails, check ESR of caps and disable unused 48V supply is
about
as far as I will go.




Isn't the Mbox Mac only?



Gareth.



It was working with whatever flavour of pc until this hash developed. No
trace of 48V anywhere. XLR mic connections traced via 6.2K droppers back to
the rectifier diode of the buck converter. Looks as though the output is
gated rather than converter switched on and off for phantom. Will try
locating data on this dodgey looking labelled soic and cut its supply anyway
and hope it is not monitored by anything

"N_Cook" wrote in message
...
Gareth Magennis wrote in message
...


"N_Cook" wrote in message
...
with USB connected but no active pc. Hash on both channels of headphone
monitoring, cycling through on about 1.1 sec period. Worse when phantom
is
on so maybe something with the 5 to 48V generator. Will try a few IC
numbers
to check DC rails, check ESR of caps and disable unused 48V supply is
about
as far as I will go.




Isn't the Mbox Mac only?



Gareth.



It was working with whatever flavour of pc until this hash developed. No
trace of 48V anywhere. XLR mic connections traced via 6.2K droppers back
to
the rectifier diode of the buck converter. Looks as though the output is
gated rather than converter switched on and off for phantom. Will try
locating data on this dodgey looking labelled soic and cut its supply
anyway
and hope it is not monitored by anything




That was going to be my next question - whether this suddenly stopped
working in a working system, or if the guy had just bought it off ebay and
couldn't get it to work.



Mind you, at this kind of price for a much better unit that probably works
in all PC's, why bother paying for a repair?

http://www.google.co.uk/products/cat...d=0CFIQ8gIwAw#

"Nutcase Kook"

I was misdirected about this but will ask here if anyone has any knowledge.
Told intermittant output so assumed mechanical socket failure. USB powered
SMD digital mixer thingy. Everything about this looks suspect except the
quality of assembly which is fine for China made, 2004
Make MBOX, model MBOX
Googling the "tick" compliance number "ACN 069 650 120" produces zilch.

** The C-tick is the Aussie designation for EMC compliance - required on
nearly all electronic devices sold here and the CE logo counts for nothing.
The ACN number refers to "Avid Technology Australia Pty Ltd " first
registered here in 1995 - no doubt as an import agent for Avid products.

Seems Avid stick all the compliance logos and required numbers for every
country on each Mbox.


..... Phil

There are threads out there on MBOX noise problems and caps.
Putting 2,000uF,10V across the USB supply seems to near enough cure it, is
that permissable, wrt USB spcifications? nonly a measly 10uF or so there as
far as I can see.
There are 4 LDO regs MIC5205B, topmarked LBAA, 3 hold their outputs but one
varies 30mV timed with the hash variation, Putting the cap there makes a
vast improvement but not quite up to the main supply smoothing. Will try
tracing all caps to that reg and replace them.