Pioneer SA-9500 II stays in protection mode

[markthefixer]

don't read too much into it, first the readings have to be absolutely repeatable. including the rails.

happenstance.

 

[tosicus]

C15 being changed to an ecq is very good thing.

protect could be several things, up to C9,C10 Q1, Q2 over current sense

BUT FIRST

does it do it when the amp is both quiet AND carrying music?
does cutting out the tone controls make any difference?


measure the DC voltage at the speaker terminals while turning up the volume knob to -37db with no audio. on this amp there is no dc offset adjust...
see if the dc voltage changes with tone control in and out, as well as various volume control settings.
we are looking for DC going into the power amp AND the input caps (c1q,C15L / R ??) leaking and letting it in.

if it does it on music only
then q1,q2,c9,c10 bear replacement. this is more likely.

does it do it when the amp is both quiet AND carrying music? Only when carrying music.

does cutting out the tone controls make any difference? Yes, it goes to protection at much higher volume -18dB

Readings at the speakers terminal, no audio: DC variable from -5mV to +5mV.
DC voltage is the same at various volume and cutting tone control.


tos

 

[markthefixer]

does it on music
q1,q2,c9,c10 need replacement.
q1,q2 512-KSC2383OTA ecb left to right, leads pointing down, flat facing you. old 2sc869 = BCE, WARNING IT IS OPPOSITE!!!!
c9, c10 667-ECQ-V1224JM

 

[tosicus]

does it on music
q1,q2,c9,c10 need replacement.
q1,q2 512-KSC2383OTA ecb left to right, leads pointing down, flat facing you. old 2sc869 = BCE, WARNING IT IS OPPOSITE!!!!
c9, c10 667-ECQ-V1224JM

I have on hands 512-KSC2383YTA, can I use them instead of 512-KSC2383OTA for q1,q2 ?

Also, for c9,c10 I have 667-ECQ-V1H224JL2, can I use them?


tos

 

[mattsd]

Yes and yes.

 

[tosicus]

does it on music
q1,q2,c9,c10 need replacement.
q1,q2 512-KSC2383OTA ecb left to right, leads pointing down, flat facing you. old 2sc869 = BCE, WARNING IT IS OPPOSITE!!!!
c9, c10 667-ECQ-V1224JM

q1, q2 replaced with 512-KSC2383YTA
c9, c10 replaced with 667-ECQ-V1H224JL2

Still goes to the protection mode.


tos

 

[markthefixer]

troubleshooting

open up D21 (lift a leg) and see if it still goes into protection (defeats over current protect)
did that stop it? (leave d21 open )
open up D22 and D23 together and see if it still goes into protection (defeats DC voltage protect)

it should still delay several seconds upon power up.

we gotta see if the protect circuit is JUSTIFIED in tripping the relay...

does recap mean c11 and c12 (330uf 6v) were replaced? Q3 and Q4 (2sc945) can be replaced with another 945 set OR a pair of ksc1845's...

 

[tosicus]

troubleshooting

open up D21 (lift a leg) and see if it still goes into protection (defeats over current protect)
did that stop it? (leave d21 open )
open up D22 and D23 together and see if it still goes into protection (defeats DC voltage protect)

it should still delay several seconds upon power up.

we gotta see if the protect circuit is JUSTIFIED in tripping the relay...

does recap mean c11 and c12 (330uf 6v) were replaced? Q3 and Q4 (2sc945) can be replaced with another 945 set OR a pair of ksc1845's...

OK, I'll do it next week. Thank you Mark.


tos

 

[tosicus]

troubleshooting

open up D21 (lift a leg) and see if it still goes into protection (defeats over current protect)
did that stop it? (leave d21 open )
open up D22 and D23 together and see if it still goes into protection (defeats DC voltage protect)

it should still delay several seconds upon power up.

we gotta see if the protect circuit is JUSTIFIED in tripping the relay...

does recap mean c11 and c12 (330uf 6v) were replaced? Q3 and Q4 (2sc945) can be replaced with another 945 set OR a pair of ksc1845's...

open up D21 (lift a leg) and see if it still goes into protection (defeats over current protect) Yes, it goes into protection.

open up D22 and D23 together and see if it still goes into protection No, it doesn't.

it should still delay several seconds upon power up. Yes, it delays about 2 seconds.

does recap mean c11 and c12 (330uf 6v) were replaced? Yes, they were replaced with 330uf 10v
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

After replacing Q3 and Q4 with 512-KSD1616AGBU, the amp doesn't go into protection anymore. My pioneer works and sounds great again!!!

Thank you all for your help, specially Mark, you are an amazing person, thank you very much!


tos

 

[markthefixer]

congratulations on several correct intuitive leaps

you have made some valuable steps towards becoming a fixer!

 

[marc brown]

SA-9500 stuck in protection mode

I have the same symptoms as the OP: my SA-9500 is stuck in protection mode. Any help is greatly appreciated.:yes:

I started a new thread