Bosch testing equipment

So it's not just us ,all the time ,poor considering it's Bosch

had a fiesta in today, started off with zero drift at 2.52, cleaned lenses and tried again, 2.48 !! cleaned out the tube between lenses, out shot a spider, egg sack and web! all good again.

its always been a problem particularly with real old smokers that max out the readings,our suns (and before that our cryptons)at my last place would show the current zero drift readings live before you entered that youd finished the test and i got to the stage that i paid REAL close attention to it cos if it was at or above 0.04 or thereabouts it would fail the zero drift test and you would have to do it again.i would clean the optics and make sure it was reading below that before i entered the finish page and yeah i know it could mean the readings would be a bit ish but on some smokers it would just fail zero drift every time no matter how many times youd tested it-and how many times do you wanna go to max revs on what is probably an old spunker to begin with-so what other choice you got?the best one we had was an old omitec that almost never failed the span check but dvsa outlawed it a few years back when they changed the specs.you will have equivalent probs with gas testers when you test-lets say-an old mini or summat or a modern car with an emissions fault,modern cat testers REALLY dont like those levels of hc and co going thru em and will almost always go pete tong for the rest of the day(if youre lucky!).could be a case for specialist emissions testers or even possibly exemptions?or maybe refuse to test on the grounds that itll fook your equipment!having said all that i now work at a dealers and rarely see the sorta sh1tty old smokers that i had to deal with all day every day for the last 40yrs.do i miss it? take a wild guess.....