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TDS684C "Cal Fails during initialization".

Reginald Beardsley
 

I've seen this error in a number of ebay listings. What does it mean? I could find nothing in the service manual, 071062702 on Tek's web site. I"d bought a LeCroy DDA-120, but FedEx dropped it, so I'm looking for another cheap 1 GHz DSO.

Is this an NVRAM failure with error messages even worse than the 11801? What is required to repair the fault? So far no search has turned up useful information.

Reg

Siggi
 

Hey Reg,

I can't speak to these errors, but wonder if you know what you're getting
into with the TDS 6XX series. These are CCD-based scopes, meaning they
capture in real time at up to 5GS/sec per channel into a CCD FIFO, which is
then digitized at a pretty leisurely rate after a trigger hits.
The upshot of this is that they have a fairly limited memory depth, and
some other acquisition quirks. The selling point for those scopes
originally is that you get the full 5GS/sec for all the channels
simultaneously.
Another thing to watch out for is that the 6XX*A*s don't have a peak detect
mode, which might be a problem - though only if you're looking at the As.

If you contrast the 7XX series, those scopes capture at up to 4GS/sec
across all channels. This is however multiplexed, so the capture rate per
channel drops off as you turn on more channels. With all four channels
turned on, you're down to 1GS/sec each.
You do however have equivalent time capture for repetitive signals, hi-res
for slow signals, peak detect across the board, and (I'd guess) much less
dead time between acquisitions.

I don't know if any of this matters to you - and apologies if I'm preaching
to the choir...

Siggi

On Sun, Dec 15, 2019 at 1:23 PM Reginald Beardsley via Groups.Io <pulaskite=
yahoo.com@groups.io> wrote:

I've seen this error in a number of ebay listings. What does it mean? I
could find nothing in the service manual, 071062702 on Tek's web site. I"d
bought a LeCroy DDA-120, but FedEx dropped it, so I'm looking for another
cheap 1 GHz DSO.

Is this an NVRAM failure with error messages even worse than the 11801?
What is required to repair the fault? So far no search has turned up
useful information.

Reg