Harman Kardon AVR260 amp, 2013

N

N_Cook

Guest
Owner went away for 2 weeks, left the amp plugged in and in standby.
Nothing else in the house was affected, but still could be a power surge
while away , I suppose.
Returned to find the functions and display work but no audio, or even
hiss on any output. No Pre-PA link that could be missing, no PROTECT
mode in the display and not stuck in MUTE. The SM is out there, but I
suspect something very silly, rather than pulling this all bells and
whistles m/c apart. Not switch mode ps, heavy lump. No relay click over
heard and the fuse/s not located yet.
 
N_Cook <diverse@tcp.co.uk> wrote:
nothing to do with the current problem. Mighty strange place to put 2x
fans, each one 20mm from a wall of unperforated aluminium, how the air
is supposed to pass and cool the H/S vanes is beyond me.
Click to expand...

Ha.

Sounds like some stellar all-around design there.
 
34 screws and numerous ribbon connectors to remove, to get the rear
panel apart , just to see let alone test the fuse that seems to pass
mains power to the big Tx , coming out of standby.
Better check there is no power going to the big Tx first. There is
little current surge at power on , so suggestive of no main Tx coming
on, just the little standby Tx.
 
nothing to do with the current problem. Mighty strange place to put 2x
fans, each one 20mm from a wall of unperforated aluminium, how the air
is supposed to pass and cool the H/S vanes is beyond me.
 
On 30 Mar 2015, N_Cook wrote:

34 screws and numerous ribbon connectors to remove, to get the rear
panel apart , just to see let alone test the fuse that seems to pass
mains power to the big Tx , coming out of standby.
Better check there is no power going to the big Tx first. There is
little current surge at power on , so suggestive of no main Tx coming
on, just the little standby Tx.
Click to expand...

No output from the headphone jack?
 
On 30 Mar 2015, N_Cook wrote:
34 screws and numerous ribbon connectors to remove, to get the rear
panel apart , just to see let alone test the fuse that seems to pass
mains power to the big Tx , coming out of standby.
Better check there is no power going to the big Tx first. There is
little current surge at power on , so suggestive of no main Tx coming
on, just the little standby Tx.
Click to expand...

Does injecting audion to a direct-input (“6-ch direct input”) get you any
output? This bypasses the preamps.
 
On 30/03/2015 19:13, DaveC wrote:
On 30 Mar 2015, N_Cook wrote:

34 screws and numerous ribbon connectors to remove, to get the rear
panel apart , just to see let alone test the fuse that seems to pass
mains power to the big Tx , coming out of standby.
Better check there is no power going to the big Tx first. There is
little current surge at power on , so suggestive of no main Tx coming
on, just the little standby Tx.

No output from the headphone jack?
Click to expand...

no clicks or hiss there
 
On 30/03/2015 19:28, DaveC wrote:
On 30 Mar 2015, N_Cook wrote:
34 screws and numerous ribbon connectors to remove, to get the rear
panel apart , just to see let alone test the fuse that seems to pass
mains power to the big Tx , coming out of standby.
Better check there is no power going to the big Tx first. There is
little current surge at power on , so suggestive of no main Tx coming
on, just the little standby Tx.

Does injecting audion to a direct-input (“6-ch direct input”) get you any
output? This bypasses the preamps.
Click to expand...

I'll try that tomorrow as well as checking for mains on the big Tx and
then a drive voltage over the D912 back emf preventer to the relay,
which is about all that is observable without taking the amp apart.
Amazing that there would seem to be 2 fuses buried at the rear , behind
the relay, cannot even see any part of them. Perhaps some traces are
probable to check those fuses without dismantling
 
I convinced myself that the low switch on surge was not for the main Tx
and should have checked there first. Went down the farting about route.
Removing a cable tie to move a filter toroid and rats nest of thick cables
I could see one end of the elusive fuse. The primary side of the Tx is
not probable except at that point and 2.1R to mains neutral, standby Tx
4.4K. Pushing a thin brazing rod through a hole in a rear pcb it was
possible to make contact with the other end of that fuse and ok.
Powering up and 5.9V over the 6V power relay and clickover.
2 lots of +/-44V dc off the main ps and 23,19,19,23 Vac on the minor
secondaries.
So next to check the minor DC rails and whether the preamp is working.
Looking more like something silly like a child-proof lockout via some
set of keypresses or something like that. But nothing like a key symbol
appearing in the display.
 
I've just noticed on the schema an insertion sense contact on the ground
of the phones socket, not found where that sensing goes , but will check
that out first
 
The phones socket insert switch is operating correctly.
Feeding signal in direct or selecting FM tuner , preset frequencies on
the display but no audio out.
The minor DC rails seem ok except the supplies to the +/-15V regulators.
Schematic shows the raw voltages should be +/-17V in use, but measure
-25V and 23V and only 18 to 20mV dropped over the
..47R fusible resistors in line . So looks as though little or no loading
of those rails.
About .2 amp stable draw from the mains and the main h/s is warm after
10 minutes or so
 
Removed the little tuner pcb to get some view room
The Power_Mute line seems to come from p38 of 100 pin Toshiba T5CC1 IC.
It is at 3.3V which seems to be for normal unmute.
Next I'll try feeding a signal directly into the edgemost chanel SBR to
confirm the amp would work if it was not killed by something in the way
of firmware or software or somesuch.
 
Just as well archive.org still has an English language version of the
user manual, as only German,Polish or Dutch seems to be available from
the h-k sites now

http://www.harmankardon.com/resources/Brands/harmankardon/Products/ProductRelatedDocuments/en-US/OwnersManual/Owner%27s%20Manual%20-%20AVR%20260%20(English%20EU).pdf

22 nov 2010 version

I'd noticed this business , but thought it was normal, not familiar with
htese sorts of beasts
"Letters flash in the Channel
Indicator Display (14) "
then goes on to say
"and Digital
Audio stops
Digital audio feed paused • Resume play for DVD/Blu-ray "

So perhaps the last useage was DVD and stopped mid-play and the AVR260
is too clever to realise that if it is switched off at the mains then an
owner is not interested in resuming play.
As I don't have that DVD and disc of last useage a "factory reset " of 5
sec press of OK while in standby mode, is called for to delete this guff
from memory
 
The reset works in the sense that legend RESET appears in display but
the memory contents are not erased ie the tuner preset frequencies are
still there
 
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