Altec 9440a

**Nite** · April 19th, 2010, 10:30 PM

The left channel on my Altec 9440a is reading -39mv DC. I erronously stated it as -39V, when I requested a manual. Bfish was kind enough to email the manual and I replaced C3, C10 and C11. C3 was definitely defective. The dc offset voltage is now -36mv.
The voltage on CR10 anode is .70VDC and on CR11 cathode it is -.70VDC. The power supply rails are within .5V of what is on the schematic. Adjusting R30 does not seem to change the offset voltage(I did not move the pot wiper to the complete end of it's travel). I removed the pot and checked it. It's total resistance is 750 ohms. Could someone shed some light on what might be defective here. The DC offset voltage on the right channel is 12mv DC....Thanks Nite

**Nite** · April 21st, 2010, 07:26 PM

This problem is solved. I can now adjust the DC offset voltage to spec. The problem was caused by several dry solder joints on the driver board. A thorough resoldering did the trick...Nite.

**Altec Best** · April 22nd, 2010, 08:43 AM

Originally Posted by Nite

This problem is solved. I can now adjust the DC offset voltage to spec. The problem was caused by several dry solder joints on the driver board. A thorough resoldering did the trick...Nite.

Thanks for posting I'm looking at a 9440A now and this info could be very useful Thanks !!!:2thumbsup: