Chris,

 

    We are both professional electrical engineers, and your points here,  are so waaaaay off.

 

    An expensive and professional level electronics product like the CP4 ... should NOT require a paper or plastic bag on it,  to operate properly.

Putting a bag over the CP4 – while that would be an appropriate look for its present state –  would be difficult with all the attached cables in the way. A “dew heater patch” under it, if there actually were enough space between its backside and its cradle to still lock it down, might work – I doubt there is. There is probably enough heat given off by the enclosed electronics, to be equivalent to using a dew heater patch.

 

    However, I was thinking about integrating a “Liquid level sensor” inside the CP4, based on its present case design status.

 

    All that AP had to do was simply to put some RTV around just that ONE leaky RJ-45 connector, or use a proper water proof Ethernet connector, similar to ALL the others on the panel, or even just stipulate that it NOT be attached  on top of the RA axle of old model mounts,  and the CP4 would be “water proofed” – but they DID NOT, couldn’t be bothered to make the effort, and AP’s  “legal disclaimer” on water resistance was an easier out, for the company.

 

    Don’t know why you assumed my CP4 and telescope is installed inside an “observatory” – I thought I made it perfectly clear,  it was NOT. You must be skim-reading,  or confusing the post with some other case.

    The site is a backyard, 20 feet from the house, in the middle of a major city of 4 million people on Lake Ontario – not out in the deep woods or farmer’s field. We don’t have “corrosive air pollution” like many places in the US or China. People in the US, and most of the world consider Toronto as one of the cleanest cities, air, streets, etc. on the planet,  and we don’t wear medical face masks when walking outdoors.  – Ever been here? – Try again, Chris.

 

     The only way it would be corrosion,  from (distilled) water “dew”, is if the circuit board wasn’t PROPERLY RINSED during manufacture,   to neutralize solder paste acid, etc. and THAT acidic water solution would definitely make the incoming dew water,  corrosive. So, perhaps it is a case of poor AP manufacturing practices? But, I wouldn’t expect that.

 

     Mainly,  it is simply a case of plain drowning, and the circuits were blowing from a string of “orange rust”, obvious in the photo, between several pins along the bottom of the PCB. That is also evidenced by a huge wide swath of  “rust stain” along the case inside bottom ledge, at the base of the circuit board, about 2 inches long – that’s REALLY significant rusting. Would you care to see Marj’s photo of the first damaged board, and mine of the second drowning?

 

   It was just normal average city dew, perhaps a bit heavier on one night,  than  average. Good grief Chris, it “wasn’t raining” from  dew at the time – the skies were pristine, since I was imaging without problems.  It also happened to TWO CP4 boards – and by the way, NEVER happened to my original two CP3 boards, after over a decade of use, in the exact same spot. But then ... CP3’s don’t leak – CP4’s can easily leak, if facing skyward, rather than being vertical.

 

    And yes, the 14.5 inch primary mirror is doing just fine, no corrosion or dulling, nice and shiny, even after more than 7 years since re-coating, and the ASUS laptop sitting right beside it,  exposed to the same environmental dew conditions, (covered by a LAPDOME, but not closed up)  didn’t short out ...  so please don’t go spinning cobwebs about corrosive air around here.

 

    Don’t know why you think the circuit board is “dip sealed”, it certainly isn’t “Potted” which would be overkill.   Perhaps you actually mean “Conformal Coated PCB Traces” -  but obviously the solder joints  are NOT – they,  and all IC’ pins are bare solder, fully exposed to water and being short circuited by water and the iron in the rust, even if the PCB circuit traces themselves,  are (green) conformal coated.

 

    The CP4 needs proper water proofing, more than your suggestion of just relying on its  “PCB conformal coating”,  since Astronomical Telescope electronics are ACTUALLY MEANT to be exposed and used outdoors, at night, even in winter conditions of wind blown snow dusting. Even some  lowly porch and garage lamps are especially required to be UL/CSA rated for water penetration, before allowed to be sold to the public.

  What makes “astronomy accessories like the CP4” ... UL/CSA exempt?

 

    I would surprised if the CP4 could have passed UL or CSA certification – didn’t find it stated in the documentation – only the  FCC radio emission standards.

 

Joe