RCA 420 No Sound

[crash2881]

Have an old RCA 420 that gets perfect video but no audio. Any ideas as to what is bad within receiver?

[crash2881]

Are you subbed with a p4 or p5?
Yes I subscribe with a P4 and always have subscribed, but I didn't use the RCA420. I got the unit from a friend who bought it defective. He never took advantage of warranty.

[Armis]

Have an old RCA 420 that gets perfect video but no audio. Any ideas as to what is bad within receiver?

Sound in a 420 is pretty basic.. The audio PCM comes out of a pin in the main processor (large, zillon pin chip), and gets sent straight to a 1bit DAC (tiny 8 pin chip) - so if you have the ability to remove a SMT chip, that would be the best bet labor-wise.

If you wanted to look at the PCM stream coming from the processor to verify with a logic probe or scope, schematic reading would be a good thing, and a 10x microscope would be most helpful to do the soldering work.

Good luck!

[m5runner]

if you have a jtag, you can bring your sound back to life. its a simple fix.


http://www.dssftp.com/forum/upload/showpost.php?p=56896&postcount=5

[sparcky1]

works like a charm. Used that on a 420 quite a while back. Just edited the eeprom myself and wrote it back to the IRD. Still not sure why the sound disappeared.