Discussion in 'Exclusively Sansui' started by Zekeman, Sep 29, 2017.
Are the measurements on the base and emitter of TR02 correct?
Bias was dialed-in correctly a couple of weeks back. I'll recheck it.
I'll post the other findings tonight. Thanks
A spark means either Hi current or Hi voltage being removed from a load.. at amp idle you should have neither....
I have been watching this thread hoping for a clue for an issue I am going to be chasing. I have a 7900Z receiver doing the exact same thing.
So it can happen. I don't see how though. DC offset is 14mv, but with tone on, a very loud pop on power off. Relay opens instantly.
Both channels. Tone off, no pop.
My first thought is power supply issue because it's in both channels, or a bad ground.
Time will tell, I hope.
The power supply is OK it's just a tad high. Not quite sure if that is significant but its not wildly off and it is consistent across all values.
When I get home I'll try the latest suggested ideas toward resolving this.
To answer your other question - the amp is properly biased at 18mV.
Regarding R-73/74....I'm getting some fluctuating values of approximately -21mV, -19mV
Sorry 2596 the protect board.. Input to the relay...
Again so I'm clear the POP only happens on power off and you are in tone on or tone and filters on .. but is OK with both tone & filters off?
If the amp is running and you switch in & out of tone and or filters No pop ?
TR02 is NPN, 10V on the base and 11V on the emitter?
Yes I believe I have a c1845 in there .
Wow this is strange......Measure the PS for the output section, does it glide down or DROP OUT when you kill power ??
Edit: This morning (Sat) I am getting Orientation OK. 11V base and 11V (stable) on emitter and 20V collector
Glides back to 0
Here are some additional values taken today and points where the pop occurs.
Separate names with a comma.