Leaving the rest of the discussion alone: If it were mine to do, I'd just hang a 60W incandescent lamp near but not touching the PCM and let it warm for a half hour or so, maybe longer if it were bitter cold out. I'd consider this much safer than any previously offered alternative.

Well, shucks, there's one thing I can't let go because it's so obviously wrong: Warming the PCM will not cause condensation to form. If anything, it will cause any previously formed condensation to (at least begin to) evaporate. It's cooling that causes condensation.

 

The terminology you chose to use -(encased in EPOXY), in the automotive or aerospace industry is used to describe encapsulation. TO ENCASE means total encapsulation and is usually associated with a dipping or potting process to where, a two-part epoxy such as Stycast is used and it fills the entire cavity like a mold. Once potted or, even coated in epoxy, it is not re-workable.

The type coating used in the 96 JTEC PCM is a CC and is on an average, a mere 25-50um thick. Dip coater leaves a 25um mil film thickness by the way and, is not usually preferred because it's an uncontrolled process, it drips, it runs, it builds up beyond the OEMs recommended mil film thickness and, if the substrate is mounted in an assembly, you can't dip it for, you'd have to submerge the entire unit if it's assembled inside the package. Most OEM contract houses use automated spray lines.

This coating is removable, it's pliable, peel-able and is not of epoxy base. CC of epoxy types from that time period were HARD and, almost impossible to cut let alone peel off the surface. I used to tint it black and coat my custom tube amp circuits to prevent / deter reverse engineering of my circuit design. The only problem using it was, it was a PITA to remove if you had to re-work it. Howard Dumble of Dumble amplification also did the same thing and became infamous for doing so.

I suggest reading the JTEC tech paper that lists the processes involved so you can read for yourself what they used in the mid 90s.

In that PCM, there were multiple points of continuity on the pins and fasteners to case (despite being CC-d) when probing lightly on the fastener head to case using the side of the probe to avoid puncturing the CC. There's quite a few areas to which, are not sealed 100% and show continuity in the unit that I've got on the bench.

These coatings also absorb moisture. They are only used to prevent dendritic growth and corrosion if there are no ionic residues or active flux residues trapped under the coating. It's certainly not used as an aid to prevent vibration failures. Those caps that I showed you earlier- those were CC-d along with the entire assembly and they flew off within three minutes of z -axis.

If these PCMs are made to JTEC STDs and, providing they were indeed made in Japan along with having been manufactured in the mid 90s by Nippondenso in their Kota Plant in Japan, the JTEC paper applies and, the coating that they call out is of CC type and, that's what's in this unit and, it's not epoxy used to "ENCASE" the unit nor protect it from vibration as you had stated.

LOL I know what CC is and it's associated processing having used Aralene, Uralane, HPA, and other non-epoxy based materials such as silicone, paraxylene, acrylics and so on. Yes, very familiar with all of this.

Since you are in doubt, I am going to provide you with my work number as well as my email address at work so you may contact me directly.

I currently hold a Sr Manufacturing Process Engineer title and yes, I know what CC is and, we don't use epoxy to coat electronic assemblies. Staking of wires using epoxy sure. Staking of fasteners with epoxy sure to potting smaller, through hole power supplies and such- yes, epoxy is used. But, CC-ing an assembly with epoxy is uncommon. Not that it's not done on other products but, I've yet to see it used as a CC on aerospace or automotive electronics.

UR, here's a test for you. Insert a drink into the freezer and pull it out, note what's on the outside as it WARMS UP. Do note that when inserting it into the freezer, it does not condense. Place it into the freezer and watch it with the door open, hell, place into the ice cube bin and note there's no condensation going on.

Do you wear eyeglasses? If so, you've probably experienced them fogging over when coming inside from the COLD. Water condenses on the lens. But, going from HOT to cold- there's no condensation. My lenses do not fog over when I walk outside into zero degree weather out here in Mass.

In summer, a cold can of beer out of the ice chest condenses as it warms up in the warmer air temp. It's going from a colder temperature to hotter temperature and, as a result, condensation forms on the outside of the can thus, water forms and leaves a ring. Same thing with a glass filled with ice- you get water rings on the table thus requiring the use of a coaster to prevent damage to the wood surface. It's going from COLD- to HOT.

But, take a room temp bottle and dump it into the freezer and keep the door open- no condensation is seen. It's going from room temp to cold- but, it's not condensing.

Ever see the inside of a thermal cycling chamber being pumped down from HOT TO COLD rapidly? There's no condensing going on.


However, when going the other way, COLD TO HOT- condensation forms on the glass and inside the chamber and on the DUT.





I think what you may be confusing is BAKE OUT or EVAP process to which, all moisture is baked out. Only if heated until sufficiently and 100% throughout, only then will all moisture has been baked out of the unit. The lightbulb is not going to be sufficient. The fastest way to do this is so simply remove the PCM from the vehicle and take it inside and let it warm to room temp. Then, place it back into the vehicle and test it. Light bulb is not going to heat it internally as most of that energy is going to be absorbed by the cold air temp vs. transferring the heat inside the box.


CM

 

Oh man, I really wish you hadn't just destroyed my professional respect for you by saying such a stupid thing so proudly.

You would have done well to have paid attention in elementary school science class.

 

I'm sorry for the poor example URU. As poor as that reads, I used that as an example as an attempt to show that cooling of the DUT / device does not lead to condensation. I think what you meant to say earlier was cooling of the AIR around the surface leads to condensation vs. cooling causes condensation.

CM

 

Have a nice day.

 

Walking into a warm room, with a cold object, will condense water right out of the air, yet. However, the PCM is going to be in an environment full of cold air..... the hair dryer will warm the air, not the air cooling on a cold object. In order for condensation to form, you have to have some moisture content IN the air...... When it is sub-freezing temps outside.... not much moisture in the air to condense.

You are far more likely to get condensation in/on the PCM bringing it into the house, than blowing warmed, already low moisture content air, at it.

Right??

 

Absolutely.

 

I know for sure, it's going to condense in the house - no doubt in my mind there. You're totally correct. But, since there's no voltage to it, it's a non-issue and, it will evaporate after a period of time in the house. You are also correct that in winter, the moisture content in the air is very low which, creates a worse situation for the ESD factor. Dryer the air, the worse that issue becomes.

I think a test is in order here because, you've got valid point about the super low moisture content in the air outside during wintertime.
CM

 

to encase an object in question is not dependent on the thickness of material used to encase said object.
if you truely knew what it is/was how it is used we all would of read about it when you opened that JTEC and posted a pic a mile away.maybe that mile was intentional to concel the fact that an epoxy is used to encase both types of pcm's in 2nd gens. in leu you wrote about "potting compounds" n such not conformal coatings.
no thx.....there it is again and again,more self promotion from christopher..........ect ect ect ect........
heres couple more pics of a 2nd gen SBEC2 pcm.as we all can see (including you christopher)that it is indeed encased in epoxy material.now the design of each pcm determines which material/epoxy is used.in conclusion we have 3 close-up pics of the 2gen pcms and both are encased in an epoxy.this suck ia had to delete the pic of the epoxyed jtec to make space for these 2 pics.hopefull someones out there can repost it.

 

How about a propane heater? No cord to run completely portable?