Audiosource amp200 cuts out

[clm811]

Hi.
I recently acquired an AudioSource Amp200 (circuit boards inside say "Amp200/300), and it plays fine for a while after power-up, but after 3-5 minutes, the right channel cuts out, followed by the left approximately 5 seconds later.

When I press the power (off) switch, there's a (very) brief burst of music, then it turns off.
As long as I wait at least 10-15 seconds before powering up again, the amp will play music, always followed within a couple minutes by the right channel muting, then the left (always 5 seconds later).

I haven't been able to find a schematic for the output section of this amp...

Anyone out there have a schematic to share?

Any ideas about what's going on and how to fix it?

Thanks for your kind assistance.

A picture of the uncovered amp is attached.

-Chas

[Ian Finch]

This generic design seems to be marketed through a variety of agencies like Ebay, Parts Connection and MCM. The brands vary so "Audiosource" is probably not the one to find schematics under. It is also marketed here in Oz under another brand again so it may prove elusive.

Otherwise, it's pretty clearly a thermal limiting issue if it takes 5 mins. to cut out - presumably with any or even no signal or output. Is that actually the case and what speakers/sound level are you using?

[clm811]

Otherwise, it's pretty clearly a thermal limiting issue if it takes 5 mins. to cut out - presumably with any or even no signal or output. Is that actually the case and what speakers/sound level are you using?

Yes, with or without a music signal present (I keep a DC voltmeter attached to te output to watch the DC offset, which is between 2-10mV), the amp cuts out within 5 minutes from "cold", and tried again soon after that, even less than one minute. The speakers are 8 ohm miniatures I always use for testing.

When tried without music signal, I do not hear any telltale "clicks" indicating that its not the protection relays that are muting the outputs... Then again there's that (very)brief burst of output (or 2-10mV DC offset) upon powering down the unit...