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Sim085 · 19 July 2018, 20:17

So I have looked for other posts which had similar problems and in one of these there was this link: http://amiga.serveftp.net/audio_repair.html

Here is says the first thing to do is to test the LF347 and the page provides expected voltage on each pin of this when switched there is no sound.

As per the attached screenshot mine look to be ok apart for pins 6 and pins 7. The linked page says these should have +2.3V but mine have +11.04V.

I remeber there was a site with the A1200 motherboard where you could select a pint and it would highlight where it ends. Does anyone have a link to this as I cannot seem to find it.

The linked page says:

"Now check the voltage on the second stage outputs (pins 1 and 7). If these are bad, voltages on U403 will be effected.
A problem here is possibly in the audio filter section, located between audio stages 1 and 2. With the computer off, measure approx 20k ohms between pins 3-14 and between 5-8."

However don't know what this means exactly.

19 July 2018, 20:17	#7
Sim085 Registered User Join Date: Apr 2009 Location: N/A Posts: 962	So I have looked for other posts which had similar problems and in one of these there was this link: http://amiga.serveftp.net/audio_repair.html Here is says the first thing to do is to test the LF347 and the page provides expected voltage on each pin of this when switched there is no sound. As per the attached screenshot mine look to be ok apart for pins 6 and pins 7. The linked page says these should have +2.3V but mine have +11.04V. I remeber there was a site with the A1200 motherboard where you could select a pint and it would highlight where it ends. Does anyone have a link to this as I cannot seem to find it. The linked page says: "Now check the voltage on the second stage outputs (pins 1 and 7). If these are bad, voltages on U403 will be effected. A problem here is possibly in the audio filter section, located between audio stages 1 and 2. With the computer off, measure approx 20k ohms between pins 3-14 and between 5-8." However don't know what this means exactly. Last edited by Sim085; 23 September 2023 at 10:50.