Yamaha CA-800 Channel Out.

[HomerJSimpson]

Back to basics, check for excessive Vdc at R and L as below
View attachment 1875174

.018 and .050

 

[HomerJSimpson]

When I test t708 in circuit I get I get .354 both ways between e and c

 

[HomerJSimpson]

When I test t708 in circuit I get I get .354 both ways between e and c

I also get .234 when testing d708 either way. In circuit.

 

[HomerJSimpson]

This may have something to do with it

 

[HomerJSimpson]

Fixed and still no relay

 

[HomerJSimpson]

13k

Was 13k now 89 ohms

 

[HomerJSimpson]

What voltage are you seeing on the base of TR708.

Was 10.85 now 14.47

 

[HomerJSimpson]

What voltage at the base of TR709 ?

Was .653 now .433

 

[HomerJSimpson]

Collector voltage of TR709 ?

Was -.017 now -.006

 

[avionic]

Was 13k now 89 ohms

Remove TR708 and remeasure.

 

[avionic]

Was .653 now .433

.653 looked better.

 

[HomerJSimpson]

What resistance are you seeing from the emitter of TR708 to chassis ?

Remove TR708 and remeasure.

"What resistance are you seeing from the emitter of TR708 to chassis ?"

Is what you asked here

how do I remove and test with no emitter?

 

[avionic]

"What resistance are you seeing from the emitter of TR708 to chassis ?"

Is what you asked here

how do I remove and test with no emitter?

Yes..Emitter solder pad. Sorry should have been more specific..

 

[HomerJSimpson]

"What resistance are you seeing from the emitter of TR708 to chassis ?"

Is what you asked here

how do I remove and test with no emitter?

Still 89 ohms at solder pad with 708 removed.

 

[HomerJSimpson]

Tr709

 

[HomerJSimpson]

Maybe having t709 in incorrectly damaged t708? Even though it's tests good out of circuit?

 

[HomerJSimpson]

Tr709

 

[avionic]

Still 89 ohms at solder pad with 708 removed

Remove C714 and remeasure.

 

[HomerJSimpson]

Good news, if I put 709 back in the way I had, the relay still clicks immediately

 

[avionic]

Are you sure you have TR708 installed correctly ?