Topic: Finally it is my time

[Aardvark]

the storm went North.  We had a family function in Minneapolis but it was a good thing we didn't go. Weather and my mother in law needed a trip to the hospital. She is fine considering, ( Low sodium levels).    We are to get some rain, right 0.01 inches. whee.   Cold then up to the 40s by mid week.

[Aardvark]

Today the transmitter board arrived, however instead of just the board, the iss unit with case  and antenna .  SO it is going to be a bit easier, all I have to do is after putting everything into setup, is go out, remove the iss unit. re install the cables and hook it up.  the older unit I can take in and at a later date disassemble it to see if it was the super cap.

I inspected the new unit . it looks like it is held in with screws (duh) and glue points.  that should be interesting.

[dalecoy]

Today the transmitter board arrived, however instead of just the board, the iss unit with case  and antenna .  SO it is going to be a bit easier,

Anything to report? 

[Aardvark]

I am sitting a 2 hour faculty meeting panting wanting to replace the unit before the sun went down. So at 3 pm I am zipping down the hall, into the ca

I took off the cover and removed the battery,  flipped on the #4 test switch and nothing.. it is being powered by the battery. So I fought removing the wires through the channel, it was tough as I have the VP2 plus with the solar/uv sensors,plus the day time FARS  which has the split solar panel so that sucker has to come out,  It was a game of seeing what order to take them out and out the opening without breaking off a plug .. I have other plugs, but I don't want to do it.

So I got it off, put the wires back and replugged the opening.    Then sun set on my parade.  So I figure that tonight it is running off the battery. Tomorrow when I get home.  I will go out and remove that battery and put in a fresh one and go from there.  Should it be sunny tomorrow the super cap will charge.

I haven't had the time to go down and take the board out of the case to check the super cap, but will get that done.  Ispent the rest of the day getting my iHome IA91  radio to play nice.  I got one.. considering I have the iphone, I kind of want a radio I can listen to my kind of music when I sleep..  I have it on my desk ready to trigger at 5:15 tomorrow morning... We'll see how it flies.

As soon as I get a free moment I'll take off the covers and remove the board and see why it isn't running off the super cap.   I 'don't think it is the panel as it is a new one.

Maybe in another year or two  I'll spring for a VP2  with a 24 hr. fan or may be I'll just not use the fan and go back to a single pane..

[Aardvark]

and the saga continues.  I got finished installing the ISS last night around sunset, so I transferred the old battery into the new unit, figuring that the super cap was empty at the time and it was.  When I got home I pulled the battery and put on the test switch and it was flashing as it was expected.  I put in a new battery. and we are good right now.   

I am hoping this weekend to open up the old unit and find out if it was the super cap or the charging circuit.  Time to snag the multimeter.

[Aardvark]

I happened to be in the basement trying to figure out why Interwarn was acting naughty and decided to open up the ISS unit.  There it is , the leaky cap.  So what wattage would you recommend to desolder the cap and put in a new one, once I get it  located and sent?

All I think I will need to do then is to connect one of the solar panels I have ( I have the original and an old 24 hr fars one)  and I should be in business for station 8.  probably another temp/humid or temp station, that would give me a full load.

[belfryboy]

The iron I use is a Metcal SP200 (35W), with a tip temperature of 412^oC (773^oF) first cut the legs from the cap and remove each leg in turn from the PCB. The negative leg has a large copper plane on both sides of the board so will require some care during removal. Adding solder to this will make pin removal easier.

[Aardvark]

The iron I use is a Metcal SP200 (35W), with a tip temperature of 412^oC (773^oF) first cut the legs from the cap and remove each leg in turn from the PCB. The negative leg has a large copper plane on both sides of the board so will require some care during removal. Adding solder to this will make pin removal easier.

can I just cut the leads on the old cap and then use the 2nd space  to put in the new one instead.

[belfryboy]

I can see no reason that you couldn't. It would certainly be easier that way.

[Aardvark]

I can see no reason that you couldn't. It would certainly be easier that way.

What I am planning is to bend the leads at a little higher rise off the board, to put in a bead of silicone clear caulk under the supercap and lower it to the board, solder in the leads and trim.  I "think" that will take the strain off where the leads go into the supercap.    From the precautions I have read, it seems that the problem is in the original manufacture , that when they are soldered to the board, stress at that point is not compensated.  It almost looks like the cap is bent to the board after the solder, rather than put the bend in the leads and lower it to the board.

I read at ArcherTrader that  a 2nd super cap can be added   http://www.archertradingpost.com/atp/index.php?main_page=product_info&cPath=1_6_9&products_id=68

[belfryboy]

The method you describe is similar to the way I would fit a component of that size to an aerospace board, so is entirely valid for this situation. Well what a way to spend Christmas eve! Have a good one!

[C5250]

What I am planning is to bend the leads at a little higher rise off the board, to put in a bead of silicone clear caulk under the supercap and lower it to the board, solder in the leads and trim.  I "think" that will take the strain off where the leads go into the supercap.

If you use silicone, it must be acetic acid-free. Many silicone glues use acetic acid to cure which will be corrosive.

Be sure to support the leads between the body of the cap and where you make the bend with something like needle nose plies (my preference is duck bill pliers). The goal is to not apply any stress to leads where they enter the case of the cap when you bend the leads.

I read at ArcherTrader that  a 2nd super cap can be added   http://www.archertradingpost.com/atp/index.php?main_page=product_info&cPath=1_6_9&products_id=68

I installed two caps, see my thread here for details. Currently only at about 14 months since the replacement, so the jury is still out on if two caps make a difference. But using the second location on an older SIM board that has two locations is certainly an option.

It's been a long time since I used an iron rated in just watts, everything I've used for many years now has had a temperature controlled tip (600-700C). So about all I could say is no more than 10-15 watts.

[Aardvark]

Most silicone seems to have acetic acid last time I used it .  Many years ago I used it to seal  in loose glass in an aquarium which would explain the deceased fish.

I am using an 18 watt  iron,  have heat sinks available and was planning on bending the leads prior to  using the board.  3M makes a double sided  mounting tape for holding things to walls for all eternity.  I could solder the cap, then insert this between the cap and the board or put it down where the cap will be, lower the cap into the board and on to the mounting thing and then solder.

As far as the 2nd cap,  Not sure if I will ... depends on if I remove the first leads  or not .   

[dalecoy]

Most silicone seems to have acetic acid last time I used it .  Many years ago I used it to seal  in loose glass in an aquarium which would explain the deceased fish.

...and so, if you go to the fish store, you can pick up a tube of sealant that does not have acetic acid...

[Aardvark]

Most silicone seems to have acetic acid last time I used it .  Many years ago I used it to seal  in loose glass in an aquarium which would explain the deceased fish.

...and so, if you go to the fish store, you can pick up a tube of sealant that does not have acetic acid...

That was 30 years ago,  I do not have fish,  in fact Long John Silvers is about as close as I get. 

I am guessing I will go with something other than sealant,  maybe just the 3M mounting strip,  I can cut it to just fit under the super cap. 

[dalecoy]

...and so, if you go to the fish store, you can pick up a tube of sealant that does not have acetic acid...

I am guessing I will go with something other than sealant,  maybe just the 3M mounting strip,  I can cut it to just fit under the super cap. 

That's fine - I was just suggesting where you could go to obtain suitable sealant for use with the supercap, if you want to use that. 

[Aardvark]

 

That's fine - I was just suggesting where you could go to obtain suitable sealant for use with the supercap, if you want to use that. 
[/quote]

thank you  for the suggestion.  Now I am curious on the new board, if it weren't so dang cold outside, I would take the cover off the board and see if how the  supercap is seated, the bottom of the leads into the super cap.  I am betting that it is the same as it always is, which makes me wonder the benefits of putting a dab of non corrosive sealer to the bottom of the super cap as a preventative or just  see how things go.

On the bright side, I have an extra ISS  that I can populate my last station transceiver with .   I am thinking.. that I have that temperature sensor out on the soil moisture station, replacing it with the old ISS instead, then I have a solar powered unit. then  buying one temperature probe and putting it in either my compost pile for the temperature (probably not)  or an additional temperature sensor for maybe the temperature in the crawl space for tickles and grins.

I am retiring at the end of May from teaching and need to keep busy  with some hobby.  Golf is out,  I don't know how to play and would be forever looking for a ball with an electronic finder circuit.  or get into bootlegging in the basement.. making more mead... that might be it.

In any case, I have learned a wealth of information since I bought the WMII  years ago, then the vp1 and now the Vp2.

[Sigdigit]

I do not have fish,  in fact Long John Silvers is about as close as I get.

You cracked me up with that one!  As far as visible signs of cap failure, my Mitsubishi rear projection TV set failed a few years ago and I had info that failed caps were probably to blame.  Inspected them and saw no obvious signs of failure so I did not have high hopes this would be the fix.  R&R'd the bank of 5 caps on the board, and presto, the thing came back to life! Moral of the story, you can't always tell bad caps by appearance.

[Aardvark]

the only thing that can be predicted is it is 9 degrees  out side and it is cold.

I am tempted when it gets warm enough and this snow melts enough to go out and pull the cover off of the  ISS and look at the super cap on the replacement board and see if it is bent at the right angle, if there is a cushion under it.

I had wondered if there were a sealent, such as maybe drop or two of superglue, it is moisture activated on the leads where they come into the supercap to maybe prevent leaking at that point.. just a thought.

[linuxfreak]

For the record:

GE Silicone I - releases acetic acid while curing

GE Silicone II - releases methanol and ammonia while curing

There was a Dow Corning RTV that released mineral spirits while curing, but haven't seen any since around 1982 when I was an electronics tech for our local steel company.

But check the darn tube before using!  I had a tube of GE II that was near the "best before" date, used it to seal a shaft seal in my washing machine and 24 hours later the stuff was still like it came from the tube! 

Hot melt glue from a "dollar store" glue gun on the board just before the cap is bottomed before soldering would be the "industry standard", many circuit boards I have worked on use either hot melt or a dab of RTV to stabilize components.

George

[Aardvark]

I probably will use some 3m mounting tape

[ed2kayak]

Aaddvark, I had to search for this thread. You never talked about the outcome. Or did I miss it?

Was it difficult?

Was it successful?

[Aardvark]

3 weeks ago I fell and broke both bones in my forearm, so I am in a cast and unable to do the replacement.  Davis was certain to say to unsolder the old leads and install the new cap in that spot rather than the other spot.    So perhaps in another month or so.

[Cienega32]

Sorry to hear that. Heal well!

[ed2kayak]

Bummer, best wishes for speedy recovery. So your data is current, are you just replacing batteries?