SANSUI AU-D55X protection Light
 

I have a Sansui AU-D55X amplifier which when pressing POWER-ON shows a
RED Flashing light labelled Protection.
The light will flash aprox 10 times in 5 seconds before the speakers
are switched on and sound is heard.
The Amplifier performs flawlessly in all functions and outputs
selected.
I just donot know whether such a delayed start is normal or not, more
over as the original owner stated that it behaved that way since day
one....

I like the idea of ...If it ain't broken, do not fix it, I have no
Operating Instructions so I am not sure.....it could be a self test?

SANSUI AU-D55X protection Light
 

It's almost certainly normal for this amplifier. I own Lux and Parasound
amplifiers that behave the same way.

It takes several seconds for the amplifier's voltages to stabilize at
turn-on. The protection circuit leaves the speakers disconnected during this
period. It then checks to see whether there's a DC offset at the output (and
possibly at other points). If there is not, the speakers are connected.

Be grateful that the amp and the protection circuit are working correctly.

SANSUI AU-D55X protection Light
 

Brasto wrote:
I have a Sansui AU-D55X amplifier which when pressing POWER-ON shows a
RED Flashing light labelled Protection.
The light will flash aprox 10 times in 5 seconds before the speakers
are switched on and sound is heard.
The Amplifier performs flawlessly in all functions and outputs
selected.
I just donot know whether such a delayed start is normal or not, more
over as the original owner stated that it behaved that way since day
one....

I like the idea of ...If it ain't broken, do not fix it, I have no
Operating Instructions so I am not sure.....it could be a self test?
Bad caps in the supply..
The protection circuit is most likely detecting excessive ripple..

Also the I've found bad caps in the protection circuit itself..

A warm up tends to make some caps perform better. At some point, it'll
get worse.
Also, you may want to check for bad joints.

SANSUI AU-D55X protection Light
 

Bad caps in the supply..
The protection circuit is most likely detecting excessive ripple..
Also the I've found bad caps in the protection circuit itself..
A warm up tends to make some caps perform better. At some
point, it'll get worse.
Also, you may want to check for bad joints.

Though it's possible there /is/ something wrong with the protection circuit,
five seconds is not an unreasonable delay. If the amp sounds okay, and works
correctly... why go poking around?

SANSUI AU-D55X protection Light
 

On 9 mayo, 09:57, Brasto wrote:
I have a Sansui AU-D55X amplifier which when pressing POWER-ON shows a
RED Flashing light labelled Protection.
The light will flash aprox 10 times in 5 seconds before the speakers
are switched on and sound is heard.
The Amplifier performs flawlessly in all functions and outputs
selected.
I just donot know whether such a delayed start is normal or not, more
over as the original owner stated that it behaved that way since day
one....

I like the idea of ...If it ain't broken, do not fix it, I have no
Operating Instructions so I am not sure.....it could be a self test?

I remember owning an Sansui amplifier that did the same thing. At
power on the protection light turned on for 5 - 6 seconds, then it
turned off and the amplifier started to operate. It did that since
new, so that´s the way the protection ciruit was designed to operate.
I think the user manual said the same.

SANSUI AU-D55X protection Light
 

I had a Sansui amplifier years back with the same protection circuit
and it did the same thing, it looks for a short across the speaker
terminals after you switch on, if all ok the light goes off.



On Sun, 9 May 2010 06:57:21 -0700 (PDT), Brasto
wrote:

I have a Sansui AU-D55X amplifier which when pressing POWER-ON shows a
RED Flashing light labelled Protection.
The light will flash aprox 10 times in 5 seconds before the speakers
are switched on and sound is heard.
The Amplifier performs flawlessly in all functions and outputs
selected.
I just donot know whether such a delayed start is normal or not, more
over as the original owner stated that it behaved that way since day
one....

I like the idea of ...If it ain't broken, do not fix it, I have no
Operating Instructions so I am not sure.....it could be a self test?

SANSUI AU-D55X protection Light
 

On 10 mei, 18:16, Meat Plow wrote:
On Sun, 09 May 2010 06:57:21 -0700, Brasto wrote:
I have a Sansui AU-D55X amplifier which when pressing POWER-ON shows a
RED Flashing light labelled Protection. The light will flash aprox 10
times in 5 seconds before the speakers are switched on and sound is
heard.
The Amplifier performs flawlessly in all functions and outputs selected.
I just donot know whether such a delayed start is normal or not, more
over as the original owner stated that it behaved that way since day
one....

I like the idea of ...If it ain't broken, do not fix it, I have no
Operating Instructions so I am not sure.....it could be a self test?

Most protection circuits wait a few seconds for voltages to equalize and
then allow the speakers to be connected to the amplifier. I would say the
5 second delay is perfectly normal.

OK, friends most of your advices and comments reinforce my idea that
there is really nothing wrong with my amplifier.
In the meantime I checked as a precaution the DC-offset at the speaker
terminals and the Bias setting driving the Main.
All measurements indicated no anomalies, so I guess it is safe to
state that a blinking PROTECTION light at start-up of my Sansui AU-
D55X is a NORMAL indication provided the speaker relay is activated in
~~5 seconds...

So..If it ain't broken, I cannot fix it....

TY
Brasto

SANSUI AU-D55X protection Light
 

On Tue, 11 May 2010 01:04:54 -0700, Brasto wrote:

On 10 mei, 18:16, Meat Plow wrote:
On Sun, 09 May 2010 06:57:21 -0700, Brasto wrote:
I have a Sansui AU-D55X amplifier which when pressing POWER-ON shows
a RED Flashing light labelled Protection. The light will flash aprox
10 times in 5 seconds before the speakers are switched on and sound
is heard.
The Amplifier performs flawlessly in all functions and outputs
selected. I just donot know whether such a delayed start is normal or
not, more over as the original owner stated that it behaved that way
since day one....

I like the idea of ...If it ain't broken, do not fix it, I have no
Operating Instructions so I am not sure.....it could be a self test?

Most protection circuits wait a few seconds for voltages to equalize
and then allow the speakers to be connected to the amplifier. I would
say the 5 second delay is perfectly normal.

OK, friends most of your advices and comments reinforce my idea that
there is really nothing wrong with my amplifier. In the meantime I
checked as a precaution the DC-offset at the speaker terminals and the
Bias setting driving the Main. All measurements indicated no anomalies,
so I guess it is safe to state that a blinking PROTECTION light at
start-up of my Sansui AU- D55X is a NORMAL indication provided the
speaker relay is activated in ~~5 seconds...

So..If it ain't broken, I cannot fix it....

TY
Brasto

I used to do Sansui warranty and found their equipment very sensitive
regarding self testing designs. Meaning that the slightest little problem
kept any protection circuit active. I was always given the tough-dog
Sansui units since nobody else had the patience, dedication and
experience to repair them.