• Stephen Biss

Flooded Sample Chamber 2

My 66 series 5000 with the flooded sample chamber is still drying out. Initially I would receive a "Processor Error" flag on startup because the DVM was fluctuating so wildly. Now the instrument starts and produces a "Diagnostics OK" on almost every startup. It is important to note that these types of startup fails or passes are NOT saved in COBRA data. The operator can safely keep trying to start the instrument again and again until a "Diagnostics OK" is indicated. Unless the operator documents such failures on paper, no one will ever know. Simply turn the power button off, wait a minute, turn it on, wait for a "Diagnostics OK", and repeat if necessary.

Once the "Diagnostics OK" is achieved on startup and the DVM has stabilized somewhat, it is pretty easy to run a stand-alone Esc Esc D diagnostics test to establish that all is well with the electronics (even though the DVM is still fluctuating). The 8000C Training Aid in Ontario says that this will indicate that the instrument is in proper working order. This type of data is stored in COBRA on the 8000C.

It is also pretty easy at this stage to generate a passed Esc Esc B test card to show, according to the 8000C Training Aid, that the instrument is capable of receiving a breath sample. Note that when a qualified technician runs a self breath test Esc Esc B he or she usually has no alcohol in their body. The instrument is processing 0 difference in DVM - the instrument is only dealing with zero readings. With an instrument in this bad condition and as long as zero hasn't dropped below true zero (see purge fail examples in previous blogs) it is still pretty easy to generate a clean Esc Esc B if you try several times. This data is NOT stored in COBRA in the 8000C.

The difficulty comes when you try to get consistent stable control checks using Esc Esc C to establish that the instrument is properly calibrated. The DVM is still fluctuating and so even though some cal checks (94 and 91) are in the acceptable range, many cal checks are too low or the instrument perceives that acetone or another interferent is present. This data is stored in COBRA on an 8000C. On a 5000C or 8000C (the instrument below is a 5000) you would have a separate test card for each stand-alone cal check so bad cal checks (such as 89, 81, and 82) could be discarded safely unless the defence has access to COBRA.

I have been experimenting with running a large number of air blanks and stand-alone cal checks with no simulator attached. My primary purpose is now to dry out the interior of the instrument. So far cal checks sometimes are good but often are unstable. I will keep trying.

Please note that these videos and blog entries are NOT evidence. They cannot be used in Court. Your lawyer will need to retain an expert scientist.

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