I have a Soundstream Angina that I recently started to repair. It needed new power supply and output MOSFETs. After replacing them the amp was able to power on. It drew about 1 amp at idle with the remote powered. I was able to get clean output from the amplifier at low volumes but since the heat sink is not attached I am not comfortable doing much more.
My questions are:
The amp turns on when I give it power on the BATT+ terminal and no remote hookup. Is this normal for these amps? I am thinking it has something to do with the "audio sensing" it is capable of doing when using high level inputs but I am using the low level RCAs so still a bit confused. It does eventually shut off after 30s-1min. I can time it exactly if that helps.
Second, the 15v +/- regulators seem to warm up pretty quickly without the heat sink. Is this normal? Or should I be looking for another fault drawing excess current on those regulators? They seem to warm up evenly but I was expecting with no audio signal they would not become hot to the touch within a minute.
Thirdly, Perry so generously shared a schematic for the Soundstream A4 series awhile ago but the Angina seems to vary a good bit beyond the power supply. Does another schematic for this amp exist?
If pictures or other/more information would be helpful just let me know and I will do my best to get what you need!
*If you are reading this before I add my tools to my signature just know I am doing it right now 🙂
Thanks!
My questions are:
The amp turns on when I give it power on the BATT+ terminal and no remote hookup. Is this normal for these amps? I am thinking it has something to do with the "audio sensing" it is capable of doing when using high level inputs but I am using the low level RCAs so still a bit confused. It does eventually shut off after 30s-1min. I can time it exactly if that helps.
Second, the 15v +/- regulators seem to warm up pretty quickly without the heat sink. Is this normal? Or should I be looking for another fault drawing excess current on those regulators? They seem to warm up evenly but I was expecting with no audio signal they would not become hot to the touch within a minute.
Thirdly, Perry so generously shared a schematic for the Soundstream A4 series awhile ago but the Angina seems to vary a good bit beyond the power supply. Does another schematic for this amp exist?
If pictures or other/more information would be helpful just let me know and I will do my best to get what you need!
*If you are reading this before I add my tools to my signature just know I am doing it right now 🙂
Thanks!
Post the DC voltage on all 3 terminals of Q17 and Q21.
I don't know what diagram you found. A search of my computer for angina came up with the attached file.
I don't know what diagram you found. A search of my computer for angina came up with the attached file.
That's the same file I found previously. It works pretty well but its not 100% for this amp. Maybe its a difference between the Angina and the Rub-Angina?
As for the measurements I got:
Q17:
1 - 9.20v
2 - 8.20v
3 - 8.80v
And Q21:
1 - 0.01v
2 - 0.01v
3 - 0.09v
As for the measurements I got:
Q17:
1 - 9.20v
2 - 8.20v
3 - 8.80v
And Q21:
1 - 0.01v
2 - 0.01v
3 - 0.09v
Also since I can't add a signature yet. I'll include my tools here:
Fluke DMM, Rigol 2 Channel Scope, Variable PSU, Weller Soldering Iron, Weller Desoldering Station, Hot Air Station
I think that covers anything that could be important here. 🙂
Fluke DMM, Rigol 2 Channel Scope, Variable PSU, Weller Soldering Iron, Weller Desoldering Station, Hot Air Station
I think that covers anything that could be important here. 🙂
When I measure resistance on Q21 I'm getting 5-15k depending on the leads and it does not seem to heat up. I did not have the remote wire hooked up when I tested the voltage since it turns on for a period without it. I just retested with the remote hooked up and got:
1 - 0.01
2 - 0.89
3 - 0.20
Still seems off. Maybe it is shorted.
Is it also normal for U6 and U7 to be hot to the touch within 30 seconds of being on with no signal or output?
1 - 0.01
2 - 0.89
3 - 0.20
Still seems off. Maybe it is shorted.
Is it also normal for U6 and U7 to be hot to the touch within 30 seconds of being on with no signal or output?
It's common for voltage regulators to heat up at idle.
Pull Q21. Does the amp still turn on without remote?
Pull Q21. Does the amp still turn on without remote?
I removed Q21 and the amp still turns on without a remote signal. I let it run until it shut off and the amp does not turn on with the remote wire now which leads me to think Q21 was working correctly. Do you agree?
Is it possible this is just an effect from the turn on circuitry for the high level inputs?
Is it possible this is just an effect from the turn on circuitry for the high level inputs?
I believe that you're right. I don't see that circuitry on the diagram so I can't be definitive.
Q21 appeared shorted because something else was driving the circuit.
Have you tried to find an owner's manual to see if this is mentioned?
Q21 appeared shorted because something else was driving the circuit.
Have you tried to find an owner's manual to see if this is mentioned?