My M44 will goes to protection mode (orange light on) after about 1 hour of play or ideal. It will need about 2 hour to rest until I can turn on again. I touch the heatsink, it is not hot at all just slight warm. Can anyone tell what should I look for or change? Recently I change all the capacitors ...

Here is how I work on M44.

Try to find the capacitor from locally, some are not available: MS250: Rail cap - couldn't find 12000uf, remain 4700uf at 35v (2pcs) Power supply caps - 4700uf at 16v (4pcs) and 1200uf at 35v (2pcs) M44: Rail cap - 15000uf at 35v (2pcs) Power supply caps - 4700uf at 16v (4pcs) One question, I saw so...

Eric, this is interesting. What is the function of the little black box behind the DMM? The test tone is from the hu or your Dell laptop?

todd217 wrote:what kind of amp and are you bridging it. with out knowing anything about the amp a would say a 40amp converter would be enough.

it is MS250. The fuse attach is 30A.

I don't know much about electronic, can anyone tell me how to calculate power use for car audio amplifier use as home audio amplifier?

AC is 110V
Watt rms of amplifier is 100 (50x2)
AC to 12VDC convertor

Thanks.

Ok, to make it clearer:
- Hiss on the left speaker, I swap speaker from left to right, right speaker got hiss.
- Hiss on the right, I swap RCA, hissing still at right speaker.

Eric, where is the output transistor?

I swap the speaker connection.

Confirm it was my spare speaker problem not the amp. After I swap side of the speaker, right side got hissing.

Eric, the bigger capacitor cost is double or triple the price of original capacitance value. I am in the mid of planning the order.

Will update once it is done.

Thanks.

Eric, thanks for the explaination.
One more question, the hissing sound on the left channel can it be fix?

Eric, your picture show different capacitance value. The 7 cap on your board is much higher than mine (470uf become 2700uf, 2200uf become 5600uf, 4700uf become 12000uf). Is there any reason you do that? What improvement? What other parts can 'upgrade'? Or this is a different model?

bogart, it is a diode with lable D3.

I don't know what value is it. Can anyone tell me?

Here is the pictures as attach.[/img]

I read through some older post about this topic and found quite a lot of information. I do this to MS250: 1. Check DC offset and found left output is 5.3mV and right is 0.5mV. There is a slight hiss on the left channel (more noticeable when the gain is 70% and more). Do I need to do anything about i...

To clarify, I have the tiny MS250 (2x50Wrms) not the big arse MS2250.

Hi all, just register and this is my first post. Last weekend when I clean up my junk, I found my old lovers, a MS250 and M44, I open it up and found out there is rust at most of the transistor legs, some is even connected to each other. The caps look ok from naked eye, the board is clean, all other...