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Classe CA-100 Soft Start Help Needed

P

psarahtonen

Member
I messed up my Classe CA-100!

I noticed a VERY faint hum coming from the toroidal transformer inside the chassis. I tried to quiet it by loosening the transformer and repositioning the rubber iso pads and cranking the bolt tight. But after doing that the amp no longer turns on.

I hear and feel the soft start initiating but there's no flashing red lamp on front and no second click of the relay. So I was wondering if the solution involves these 3 touch points on the circuit board under the relays. SEE PICS

They are labeled SS-RLY and RESET and then a third one labeled OFF. Do I need to supply a small voltage to these to reset the relay or soft start circuit?

Thanks!
-Kc in Austin

IMG_9309_mu.jpg IMG_9308_mu.jpg
 
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Did you smash or tear the rubber insulating pad on the toroidal transformer. That could create a shorted winding condition.
 
Check wiring for the transformer. May have pulled a wire loose.
 
psarahtonen said:
So I was wondering if the solution involves these 3 touch points on the circuit board under the relays. SEE PICS

They are labeled SS-RLY and RESET and then a third one labeled OFF. Do I need to supply a small voltage to these to reset the relay or soft start circuit?
Click to expand...
Not sure.. The service manual does not indicate anything about those test points.
 
avionic said:
Not sure.. The service manual does not indicate anything about those test points.
Click to expand...
yeah... It's printed as if it is some circuit board standard but I've never come across something. And if there's a measurement that I"m supposed to take there I have no way to know what I should be seeing.

Thanks for your help!
 
psarahtonen said:
I messed up my Classe CA-100!

I noticed a VERY faint hum coming from the toroidal transformer inside the chassis. I tried to quiet it by loosening the transformer and repositioning the rubber iso pads and cranking the bolt tight. But after doing that the amp no longer turns on.

I hear and feel the soft start initiating but there's no flashing red lamp on front and no second click of the relay. So I was wondering if the solution involves these 3 touch points on the circuit board under the relays. SEE PICS

They are labeled SS-RLY and RESET and then a third one labeled OFF. Do I need to supply a small voltage to these to reset the relay or soft start circuit?

Thanks!
-Kc in Austin

View attachment 1318639 View attachment 1318640
Click to expand...
While messing with the transformer. Was the amplifier still hooked up to your speakers?
 
Need to check for the 12v (+VB) supply voltage to the SS circuit.
 
psarahtonen said:
hey are labeled SS-RLY and RESET and then a third one labeled OFF.
Click to expand...
I suspect these are just convenient test points. Need the +VB power supply functional to reset the 4013B flip-flops( IC1a&b).The 4013B controls the SS relay RLY2.
 
Last edited:
I suspect you pulled a transformer wire loose from bridged rectifier BR1.
 
avionic said:
I suspect you pulled a transformer wire loose from bridged rectifier BR1.
Click to expand...
Thanks Avionic! I'll look into the rectifier and relay reset. And no, the red LED does not come on at all. The only thing that activates when hitting the power button is a solid CLICK sound (that does not happen when the unit is unplugged).
 
psarahtonen said:
No, not connected to speakers or anything else. How much voltage is needed to reset the flip-flop circuit? Will a 1.5V battery work just to test the theory?
Click to expand...
Unlikely.. See post # 10. You need the power supply 12v +VB power supply functioning.

Do you have a multimeter?
 
psarahtonen said:
The only thing that activates when hitting the power button is a solid CLICK sound (that does not happen when the unit is unplugged).
Click to expand...
Sounds like the SS circuit is working. That click sound would be the softstart relay setting.
 
You probably don't have a SS issue. Have you physically checked the integrity of all the transformer wire connections?
 
The +VB 12v has to be there in order for the relay to set.
 
Does this unit have a second smaller transformer ? The service data I have is a little unclear as to where the 12 volt PS gets its AC. Possibly from the main toroidal secondary winding or a secondary transformer.
 
IT'S OVER! I just smoked C220 while listening to which relays were clicking and which were not.

Thanks for your help anyway. I wish I had learned something from this very expensive lesson.
 
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