Yamaha CA-1010 Project

Does the relay right behind the power meters switch "click" when switching from normal to class A ?
 
avionic said:
Does the relay right behind the power meters switch "click" when switching from normal to class A ?
Click to expand...

You know what the relay behind meters, it is not engaging. The one on the power board is though.

Think I have a bit of work ahead of me.

avionic said:
Well..:scratch2: Replace the two fuses. And we will go from there.
These fuses are for the un regulated B+/- voltage for both Class AB and A.
Click to expand...

Replaced the two non-functioning fuses.

------
Note: when normal class set, the front relay engages.

When Class A set the relay on the power board engages not the front.
 
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You know what the relay behind meters, it is not engaging.
Click to expand...
Check the voltages around TR221
E---8.9vdc
B---8.25vdc
C---8.85vdc
 
langston said:
I assume you are referencing the wires coming off the power board. since those have labels e, b, c correct?
Click to expand...

No. I'm referring to the emitter, base and collector of TR221.
 
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avionic said:
No. I'm referring to the emitter, base and collector of TR221.
Click to expand...

TR221 is located on the small board that the mode switch is soldered to.

Yellow---emitter
Red------collector
Blue-----base
 

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avionic said:
No. I'm referring to the emitter, base and collector of TR221.
Click to expand...

My meter readings are wonky.

Normal class setting
Black meter lead third leg Yellow side transistor
Red meter lead middle leg
00.09 v

Black meter lead third leg yellow side transistor
Red meter lead left leg
00.74 v

Class A setting
Black meter lead third leg yellow side transistor
Red meter lead middle leg
00.00 v

Black meter lead third leg yellow side transistor
Red meter lead left leg
00.68 v
 
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No your meter isn't wonky.. Ground the black meter lead to chassis ground.(the metal chassis is fine) With the Red probe measure the voltages at each test point one at a time ie. emitter , base , and collector.
 
Testing as described outputs following info.

Set at class A
Yellow 12.69v
Red 12.66v
Blue 11.88v

Set at normal class
Yellow 12.06v
Red 11.93v
Blue 11.28v
 
Might have a welded relay..Or a broken or dirty mode switch.
 
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avionic said:
Might have a welded relay..Or a broken or dirty mode switch.
Click to expand...

The relay behind the meters is new, and engages in normal class.

The relay on the power board was not changed out, and it engages when set at class A

I will look over the switch.
 
You know what the relay behind meters, it is not engaging. The one on the power board is though.

Think I have a bit of work ahead of me.
Click to expand...

You said the relay was not engaging !

Forget the "mode switch " apparently its working.

Have you tried adjusting class A bias after replacing the 10A fuses?
 
langston said:
The relay behind the meters is new, and engages in normal class.

The relay on the power board was not changed out, and it engages when set at class A

I will look over the switch.
Click to expand...

Behind meter relay is strickly for Normal/Class A rail voltage switching

Relay on the power board is "speaker protection" and should "set" or "reset" in either modes.
 
avionic said:
Check the photo again.. And measure the resistance across the switch contacts ( Without power applied!).. Measure both positions (Class A/ Normal).. Class A should show continuity.. Normal should read "open"

http://www.audiokarma.org/forums/showpost.php?p=6673962&postcount=86
Click to expand...

Class A reads continuity.

Normal reads "open"


avionic said:
You said the relay was not engaging !

Forget the "mode switch " apparently its working.

Have you tried adjusting class A bias after replacing the 10A fuses?
Click to expand...

Yes Class A is adjustable now


avionic said:
Behind meter relay is strickly for Normal/Class A rail voltage switching

Relay on the power board is "speaker protection" and should "set" or "reset" in either modes.
Click to expand...

Okay.

I apologize for the errors.
 
When Class A set the relay on the power board engages not the front.
Click to expand...

So..Its going into protect when you switch to class A. Check your DC offset at the speaker jacks in normal mode. Then switch to class A and recheck.
 
Adjust VR302 on both amplifiers fully counterclockwise. Make sure those 10A fuses you installed are still good.
Power it up and see if the protect relay still resets when you flip the mode switch to class A.
 
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