Recent content by Chapmro

Fixed the tuning problem -- it was the LM7000.

So, it looks like the frequency displayed in the LCD comes from the microcontroller, the same signals that get sent to the PLL freq. synthesizer chip. Which explains why the audio and the display don't match -- the error is downstream from the microcontroller. The PLL intializes in an...

The schematic and service manual are available free at hi fi engine. The third chip in the tuner is LA3401. So far the weirdest thing I have found is that one of the test points, TP7, labelled "tuning" seems to increase linearly with the frequency tuned, going from 0v at 87.5Mhz to 30.5v at...

The PS voltages are all good. Checking the test point voltages against the schematic now, and reading the datasheets on the LM7000 and LA1266 chips.

I hope this is the right place to post this, since it deals with the tuner section of a receiver. I have an NAD 705 I've owned since new. The amplifier part still works fine, and it plays all sources except the tuner perfectly, good audio quality, all switches and dials and display works. What...