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Solderbro · 08 July 2018, 19:49

Hello,

if things become broken rare parts are involded. One of my A600 won't play sound at right channel. So i checked the recapped capacitors back to the LF347 opamp. Here i found out that the first opamp did get a sound signal from Paula, between sits a MPF102 Mos FET that pulls the signal down to zero. The second opamp only get the zero on it's input pin.
At left channel the audio signal is seen at both opamp and the MPF102.

So i think the MPF102 is shot through in some way, problem is that this piece is EOL. A search have shown that the MMBFJ113 is available, seems to have similar pinning, so i ordered 3 of them.

Do anyone had some repair in the audio amplifier and what compatible parts can be used today?

08 July 2018, 19:49	#1
Solderbro Registered User Join Date: Jun 2018 Location: Hamburg Age: 55 Posts: 56	A600 / 1200 Audio preamp Hello, if things become broken rare parts are involded. One of my A600 won't play sound at right channel. So i checked the recapped capacitors back to the LF347 opamp. Here i found out that the first opamp did get a sound signal from Paula, between sits a MPF102 Mos FET that pulls the signal down to zero. The second opamp only get the zero on it's input pin. At left channel the audio signal is seen at both opamp and the MPF102. So i think the MPF102 is shot through in some way, problem is that this piece is EOL. A search have shown that the MMBFJ113 is available, seems to have similar pinning, so i ordered 3 of them. Do anyone had some repair in the audio amplifier and what compatible parts can be used today?