Moisture-Proofing the Griso Digitek Dashboard merged threadfest (w/ new Part 4)

[LaMojo]

You may want to investigate conformal coatings to seal the circuit board against corrosion and short circuits.

[oldbike54]

 Moto , you are doing a great service to the community , thought we should merge all of this together so folks could access it easier . Thanks .

 Dusty

[lucian]

Just a thought on the subject, How about a small air scoop with a venturi fitting connected via tubing to one of the dash vents to create a draw while riding. Then connect the other dash vent via tubing to the headlight housing at a point where you would be drawing air heated and dried by the headlight. Seems like the headlight could serve as a freebe air drier.

[normzone]

You may want to investigate conformal coatings to seal the circuit board against corrosion and short circuits.

That's a good suggestion.

On the gripping hand, be advised that in working with conformal coated PCBAs in my day job, despite good intentions, professional suppliers, detailed masking instructions, experienced personnel, and prayers, we lose about 1 in 10 of the devices we conformal coat due to the stuff getting in someplace we did not want it to be.

So when we have an order for ten computers with conformal coated motherboards, we cross our fingers and hope we don't wind up needing eleven.

 

[Moto]

You may want to investigate conformal coatings to seal the circuit board against corrosion and short circuits.

Please see the third part of my original postings for instructions on how to do that:

Part 3. Applying a Conformal Coating

By the way, as mentioned in that part, using a UV flashlight is a big help in preventing coverage omissions. (Using your head is the only way to avoid getting the stuff where you don't want it, unfortunately.)

[Moto]

Moto , you are doing a great service to the community , thought we should merge all of this together so folks could access it easier . Thanks .

 Dusty

Thanks! I think now I should have posted all three parts as a single document. I've gone back and added links among them to help readers follow what I had in mind, a coherent development of theoretical and practical ideas.

Moto

direct links to the parts:

Part 1. Theory and Dashboard Design 

Part 2. Adding  a Desiccating Breather 

Part 3. Applying a Conformal Coating

[oldbike54]

Thanks! I kinda wish now I had posted all three parts as a single document. I've gone back and added links between them to help readers follow what I had in mind, a coherent development of theoretical and practical ideas.

Moto

 No worries Mate , anyone savvy enough to understand what you are doing here can sort it out 

 (Meaning the average member of WG  )

  Dusty

[Moto]

(Meaning the average member of WG  )

  Dusty

 

[Moto]

Just a thought on the subject, How about a small air scoop with a venturi fitting connected via tubing to one of the dash vents to create a draw while riding. Then connect the other dash vent via tubing to the headlight housing at a point where you would be drawing air heated and dried by the headlight. Seems like the headlight could serve as a freebe air drier.

Interesting idea. But heating the air won't really remove the moisture, but only lower the relative humidity. If the air can still cool once it gets to the dash, you're no better off.

Some electronics enclosures in extreme conditions are protected from condensation by expensive, custom heating systems. So heating the dashboard interior directly, under thermostatic control, might be a good approach while the motorcycle is operating. But overnight, when it's parked and the temperature drops, no help.

[Moto]

GMs Optispark used a vacuum to pull ozone and moisture from the ignition system. Would it be possible to hook up a vacuum line from the intake for a mild suction?

As I said before, this is a neat idea. But maybe better for protecting a timing system as in the GM vehicles.

The problem I now see is that connecting the intake vacuum via a hose to the dashboard would lower the pressure at the sensor on the PCB, which is trying to gauge atmospheric pressure. Maybe this effect could be minimized with the right choice of orifice sizes, but it might be hard to figure out.

[Moto]

...
The only way to control it is to hermetically seal the instrument with dry air or an inert dry gas or to improve the internal ventilation so the moist air has the ability to exit the instrument housing before it gives off too much water vapor that's looking for somewhere to condense.
...

Hermetic sealing is not appropriate because of the air pressure sensor on the PCB. See Part 1. Theory and Dashboard Design  .

[lucky phil]

Hermetic sealing is not appropriate because of the air pressure sensor on the PCB. See Part 1. Theory and Dashboard Design  .

I know that's why simply improving the venting fixes the issue. All that needs to be done is improve the vents and and insure the instrument internals are protected from direct water spray. Its been working for more than 50 years. The issue only arose when companies started getting silly with sealing instruments. Electronic boards can survive quite happily without being in a fully sealed housing.
This is the opinion of an instrument maker and repairer here in Australia long since retired. I asked him back in the 80's why my K100 instruments kept fogging and he showed me a few he had in his shop that were beyond fixing. He advised when BMW sent out the contract for instruments and VDO won the contract and that is what they provided, basically a sealed instrument. Why because that's the way they do things, that's why. Even after he visited the VDO factory and showed them the results.
So what was his fix? as I said before open up the existing vents or create new ones. Its worked for me on 2 bikes now but if you want it to be more complicated than it needs to be then go right ahead.

Ciao

[tris]

Increasing the ventilation by putting some bigger holes in the back was my preferred solution.
But the risk in damaging the clocks to get enough access was a step to far for me.
So my solution with an option to"upgrade" to pumped ventilation seemed the best compromise.

[Moto]

I know that's why simply improving the venting fixes the issue. All that needs to be done is improve the vents and and insure the instrument internals are protected from direct water spray. Its been working for more than 50 years. The issue only arose when companies started getting silly with sealing instruments. Electronic boards can survive quite happily without being in a fully sealed housing.
This is the opinion of an instrument maker and repairer here in Australia long since retired. I asked him back in the 80's why my K100 instruments kept fogging and he showed me a few he had in his shop that were beyond fixing. He advised when BMW sent out the contract for instruments and VDO won the contract and that is what they provided, basically a sealed instrument. Why because that's the way they do things, that's why. Even after he visited the VDO factory and showed them the results.
So what was his fix? as I said before open up the existing vents or create new ones. Its worked for me on 2 bikes now but if you want it to be more complicated than it needs to be then go right ahead.

Ciao

Lucky Phil,

You confused me. First you were in favor of hermetic sealing, and now you're against it. Yes, venting could work, especially in Australia where you and your retired guru are. That's what, the driest inhabited continent overall?

I remember that I had absolutely no use for umbrellas or hats when I grew up in southeast Idaho, another semi-desert region. We had thunderstorms, but I didn't care because it seemed like I was dry again by the time I walked 100 yards, due to the low humidity. (The humidity actually stays low in storm conditions, and dries things off right after the rain stops.) But here in the eastern part of the country, things ain't the same. Umbrellas rule. Your conditions may be favorable to ventilation.

Tris, if you want to drill holes in the enclosure it's not necessary to do anything directly dangerous to the electronics. You need to separate the top and bottom halves of the enclosure. You'll need to drill that small hole through the faceplate to get at the screw shown in my instructions for conformal coating: Part 3. Applying a Conformal Coating. You can then perforate the lower case as much as you like.

I doubt that manufacturers of electronics are designing enclosures "because that's the way they do things, that's why," in Lucky Phil's memorable turn of speech. The Griso dash does show some signs of good enclosure design, such as its very low headroom between electronics and the case, which is used to minimize the volume of air, and thus water vapor subject to condensing. Not to mention the mysterious, half-completed hose ducting I described in Part 2. Adding  a Desiccating Breather.

Go for it if you like. In my climate, I'd be checking for mold.

Moto

[ILM Rosso]

Brilliant post, analysis, and documentation!  I'd like to share some electrical protection products that I've had good luck with. Corrosion Block corrosion protectant (@ marine stores); spray on all electrical plugs/connectors. Also, CRC makes a product called 2-26 (at big box home improvement stores and electrical supply counters) that I've routinely sprayed on the circuit boards in my heat pumps (started years ago, we live on the coast) that improves electrical properties, displaces moisture, can eliminate electrical shorts, and is plastic safe. Also, of course, there's di-electric grease (use as directed). IMHO, FWIW, YMMV. Bon Chance!

Mark

[Moto]

Moisture-Proofing the Griso Digitek Dashboard

Part 4. Roy-Type Breather

This is my revised breather, inspired by a PM comment from Kiwi Roy. The original breather made of a gasoline filter had insufficient clearance for adding the desiccant beads, and insufficient capacity overall. So I made a new version using 1/2-inch ID vinyl tubing, about 10 inches long:





Vinyl tubing tip: Often this type of tubing has been collapsed by storage on a roll when you buy it. To reshape it to have a circular cross-section, plug one end with a stopper and fill the tube with boiling water.

I stepped up the connection from the 1/4-inch ID tubes going to the dash by using short lengths of 5/16" I.D. x 1/2" O.D. tubing at each end:



At the forward end I glued the 1/2" I.D. tube to the 1/2" O.D., so the screen is still retained when and if the desiccator needs to be removed from the bike. On the aft, I glued the 5/16 ID/OD interface instead, leaving the 1/2" one a sliding fit so that I can separate at that joint to obtain a larger hole for filling the tube with desiccant. There will be no need to remove the desiccator for refilling, since the aft end can be tipped up or down as needed once the u-shaped connector has been removed.

The photo at the top shows two white cotton plugs intended to restrict the movement of the desiccant beads. But I replaced the forward one with a piece of window screen to improve the air circulation between the dash and the desiccant, as shown in the figure.

The u-shaped connector on the aft end is blocked on one side with glue, and has a pin hole on the other side to provide the only (planned) venting to the atmosphere (which is needed for the air pressure sensor on the dash's PCB). When it is installed (for normal use) the top tube from the dash is plugged, and the bottom tube can breathe through the pin hole, via the desiccant chamber:



The purging pump in the schematic diagram is a 12v aquarium pump, which is attached to the breather after removing the u-shaped connector. It can then be run with a fresh desiccant charge to dehumidify the dashboard as needed. Once the dash is dried out, another filling of desiccant replaces the original one.

Performance

I did not seal the dash as well the second or third time as the first, so the balloon test I showed earlier was not as successful. My experience with the breather so far is fairly disappointing, since the indicating desiccant beads turn purple over the course of week or so, without going through particularly damp conditions. I recommend doing the best possible sealing on the system.

EDIT: Later experience has been more promising. See this update: http://wildguzzi.com/forum/index.php?topic=84968.msg1357161#msg1357161

In my own case, my dash's PCB is apparently undamaged, and is now protected by a conformal coating. So I'll be surprised if I have trouble.

Desiccant can be bought in large containers (as pictured earlier), and can be dried out in the oven (at about 225 degrees, I recall).

In the Griso installation you can look through the vent grill on the gas tank wing with a flashlight to check the color of the beads. They're cobalt blue when they're fresh, and purple went they're spent.

Moto

Skip to:
Part 1. Theory and Dashboard Design 
Part 2. Adding a Desiccating Breather
Part 3. Applying a Conformal Coating

[lucky phil]

Moisture-Proofing the Griso Digitek Dashboard

Part 4. Roy-Type Breather

This is my revised breather, inspired by a PM comment from Kiwi Roy. The original breather made of a gasoline filter had insufficient clearance for adding the desiccant beads, and insufficient capacity overall. So I made a new version using 1/2-inch ID vinyl tubing, about 10 inches long:





Vinyl tubing tip: Often this type of tubing has been collapsed by storage on a roll when you buy it. To reshape it to have a circular cross-section, plug one end with a stopper and fill the tube with boiling water.

I stepped up the connection from the 1/4-inch ID tubes going to the dash by using short lengths of 5/16" I.D. x 1/2" O.D. tubing at each end:



At the forward end I glued the 1/2" I.D. tube to the 1/2" O.D., so the screen is still retained when and if the desiccator needs to be removed from the bike. On the aft, I glued the 5/16 ID/OD interface instead, leaving the 1/2" one a sliding fit so that I can separate at that joint to obtain a larger hole for filling the tube with desiccant. There will be no need to remove the desiccator for refilling, since the aft end can be tipped up or down as needed once the u-shaped connector has been removed.

The photo at the top shows two white cotton plugs intended to restrict the movement of the desiccant beads. But I replaced the forward one with a piece of window screen to improve the air circulation between the dash and the desiccant, as shown in the figure.

The u-shaped connector on the aft end is blocked on one side with glue, and has a pin hole on the other side to provide the only (planned) venting to the atmosphere (which is needed for the air pressure sensor on the dash's PCB). When it is installed (for normal use) the top tube from the dash is plugged, and the bottom tube can breathe through the pin hole, via the desiccant chamber:



The purging pump in the schematic diagram is a 12v aquarium pump, which is attached to the breather after removing the u-shaped connector. It can then be run with a fresh desiccant charge to dehumidify the dashboard as needed. Once the dash is dried out, another filling of desiccant replaces the original one.

Performance

I did not seal the dash as well the second or third time as the first, so the balloon test I showed earlier was not as successful. My experience with the breather so far is fairly disappointing, since the indicating dessicant beads turn purple over the course of week or so, without going through particularly damp conditions. I recommend doing the best possible sealing on the system.

In my own case, my dash's PCB is apparently undamaged, and is now protected by a conformal coating. So I'll be surprised if I have trouble.

Desiccant can be bought in large containers (as pictured earlier), and can be dried out in the oven (at about 225 degrees, I recall).

In the Griso installation you can look through the vent grill on the gas tank wing with a flashlight to check the color of the beads. They're cobalt blue when they're fresh, and purple went they're spent.

Moto

Skip to:
Part 1. Theory and Dashboard Design 
Part 2. Adding a Desiccating Breather
Part 3. Applying a Conformal Coating

I cant believe this didn't work

Ciao

[swooshdave]

Brilliant post, analysis, and documentation!  I'd like to share some electrical protection products that I've had good luck with. Corrosion Block corrosion protectant (@ marine stores); spray on all electrical plugs/connectors. Also, CRC makes a product called 2-26 (at big box home improvement stores and electrical supply counters) that I've routinely sprayed on the circuit boards in my heat pumps (started years ago, we live on the coast) that improves electrical properties, displaces moisture, can eliminate electrical shorts, and is plastic safe. Also, of course, there's di-electric grease (use as directed). IMHO, FWIW, YMMV. Bon Chance!

Mark

Sometimes the simplest fix is the best. In this case protect the electronics with suitable coatings.

Powered aquarium pumps and plumbing seem to add complexity and failure points.

[Moto]

Sometimes the simplest fix is the best. In this case protect the electronics with suitable coatings.

Powered aquarium pumps and plumbing seem to add complexity and failure points.

I did coat the electronics. See Part 3.

The aquarium pump is a maintenance tool, not a potential failure point in the system.

[Moto]

I cant believe this didn't work

Ciao

No, I'd say it DOES work. There is no moisture inside the dash. The problem is the length of time before the desiccant needs to be refreshed, and I might be too pessimistic on that. At least it's easy to replace the desiccant when using the new system.

The maintenance interval for desiccant replacement is a function of how well the dash is sealed up. I could have disassembled it again after my balloon test was marginal for the last re-assembly. If I had, I might have applied some sort of pliable sealant around the rubber seal of the multi-pin connector. As it was, though, I knew I had a pretty good solution with the conformal coating, so I couldn't be too bothered to go through the sealing again. Anyone relying on the breather solution alone should be more thorough. But, to repeat, it does work. It's just a matter of how often the desiccant needs attention. Maybe I'll report back on that again after I have more experience.

M.

[swooshdave]

I would suggest you don't need the desiccant just air flow.

I think I suggested it earlier but a vacuum line from the manifold to the instrument cluster would pull air out along with the humidity. Simple enough to test. You'd want an inlet hose drawing warm, dry air. Before the carb/throttle body works, so air box. If you have one.

[Moto]

I would suggest you don't need the desiccant just air flow.

I think I suggested it earlier but a vacuum line from the manifold to the instrument cluster would pull air out along with the humidity. Simple enough to test. You'd want an inlet hose drawing warm, dry air. Before the carb/throttle body works, so air box. If you have one.

I replied before that I would be concerned this approach might mess up the air pressure sensors' signals to the ECU, but who knows? (There are two sensors, one in the air box and one on the dash PCB; the ECU is concerned with the difference in their readings, I believe, and opening a passage between them would alter that.)

I'm done with this project, having completed the job two different ways with satisfactory results. I hope you'll pursue your approach and give us a report!

[lucky phil]

No, I'd say it DOES work. There is no moisture inside the dash. The problem is the length of time before the desiccant needs to be refreshed, and I might be too pessimistic on that. At least it's easy to replace the desiccant when using the new system.

The maintenance interval for desiccant replacement is a function of how well the dash is sealed up. I could have disassembled it again after my balloon test was marginal for the last re-assembly. If I had, I might have applied some sort of pliable sealant around the rubber seal of the multi-pin connector. As it was, though, I knew I had a pretty good solution with the conformal coating, so I couldn't be too bothered to go through the sealing again. Anyone relying on the breather solution alone should be more thorough. But, to repeat, it does work. It's just a matter of how often the desiccant needs attention. Maybe I'll report back on that again after I have more experience.

M.

Well I'm glad that in your mind it worked and was worth the effort. Perfect outcome.

Ciao 

[Bill E.]

Anybody try a gore-tex vent instead of the dessicant?

[Moto]

Anybody try a gore-tex vent instead of the dessicant?

Gore-tex allows water vapor -- gaseous water molecules -- to pass, while repelling water droplets. Therefore, it would allow the interior humidity level to track the outside conditions, leading to condensation when the temperature falls and humidity is high.

Gore-tex is great for making jackets because human bodies sweat. It allows the high humidity level inside the jacket to equilibrate with the outside humidity level. Instruments have different requirements.

[Moto]

Here are two small updates to my earlier posts about my moisture-proofing investigations.

I was too pessimistic about the desiccating breather's performance earlier, after I had examined the desiccant through the grating on the gas tank wing and thought it had all turned purple. I changed it out for a new charge recently and found that about 40% of the beads were still blue, indicating they were still good. The blue beads seemed to be near the center of the tube, surrounded by purple ones. So the charge as a whole was still effective.

Earlier today I purposely sought out some passing storms, riding around in the rain for a couple of hours to see how the breather did. (Anything for science!) When I got home I observed that the first half-inch of beads closest to the pin-hole orifice had turned purple. Then I hooked up the purging pump to circulate the air in the system through the desiccant. I was surprised that this turned the purple beads back to blue, leaving the whole breather blue. So I conclude that a small amount of moisture entered the system through the pin hole while riding through the storms, but that the system as a whole remained dry. The breather seems to be working as planned. I should mention that I have an OEM flyscreen on my Griso, and that it probably helps too.

The other update concerns the disassembly of the dash to apply a conformal coating. I now realize that drilling a small hole through the tachometer face was probably unnecessary. Once the tachometer needle is removed, I'm pretty sure the face could be pried up around its center with a putty knife in order to remove it entirely. Then the screw that prompted me to drill a hole could be accessed. (Thinking back, I drilled the hole before I removed the needle, and before I knew that I would have to remove the needle to get the access I needed to the circuit board.)

Moto