Lexicon PCM70 - All OK but no output :o/

[nathaimu]

Hi everyone.
I just registered to get some help (if possible) as I have seen some people look pretty able with lexicon devices.

Here is the story :
I just got a PCM70 for free from a friend ho told me it didn't work anymore (and he wanted to thank me for some help).
- Everything looks fine with the device, audio gets through in BYPASS mode, the menus look OK, the input meter works fine and does what it should.
- An electronics expert has inspected the device, and said to me the analog part is OK, but he couldn't do more as he doesn't know anything about lexicon.
- I have performed a complete reset a few times
- I have changed ADC0804 LCN (I found it in a shop nearby for 6€ so I thought why not)

Still no audio. When I play with the mix, it works but only clean sound go through, no wet sound.
When I listen to wet sound through a pre-amp I can hear some dry sound very faintly.

That's it, I don't really know what to try next, and I would REALLY love to get it to work. If you have some ideas...

Best to all of you.

 

[pvision]

What program is it running? Does it change programs and does it remember the last program when turned off & on again?

They have on-board batteries so expect a sticky mess on a circuit board…

If it passes audio in bypass but no wet sound then maybe it's outputting nothing at all.  If the meter works then logically the input stage is OK. If it works in bypass I'd find a schematic and see where the bypass switching takes place in the signal flow. Then look there and directly before it

Great piece of kit, the PCM70

Nick Froome

 

[nathaimu]

Sorry for the (VERY) late answer.

Thanks a lot for the info.
I'll investigate that way when I have some time next weak, and post my results.

Thanks again.

 

[AK79]

batteries are lithium so unlikely that theres any leakage that causes the problem .


the pcm 70 uses VCAs to mix dry and wet signals so it may be an issue with the control voltage that is used for that .
Or the DAC isn´t working. Or filters following the DAC are faulty.

It is a complex unit that has plenty sources of failure.

cheers
Arne