Converter Part Detached

[BDandTTs]

We've relocated the Parallax Electronic 7300 converter in our 22' CCD. Noticed while moving it that something was loose in the lower compartment. We removed the front panel completely and found an unattached black cylinder as well as a vacant spot that appeared to be it's former resting space. Photos are attached.

We've reconnected the converter wiring, reattached the battery, and plugged the trailer into AC -- all appears to be working. BUT, we're concerned.

Can anyone give us information on the black cylinder? It appears to be identical to the one in the lower left of the converter, but is scuffed up a lot and printing is not readable. We assume it has been floating loose for some time. What is it? Is it necessary? Can/should it be replaced? Any help would be appreciated.

[Phoenix]

That is an electrolytic filter capacitor, which is part of the power supply. You definitely need to replace this part; and I wouldn't recommend using the converter until you do. While it may continue to run for awhile, its absence from the circuit may cause very costly repairs.

If you work on electronics, you can probably get a replacement part from Radio Shack or an electronics parts place. On the Web, try Matt Electronics; although they require a minimum order (I think $50), which is way in excess of the cost of the capacitor. If I had to guess, this part should only be a few dollars (if that); although it is hard to tell without being able to see the codes on the side of the component.

Since this is in a device that has 110 VAC present, you should take extra care to completely disconnect the converter from the AC voltage before working on it, as there is an electrocution hazard. If you are not familiar with electronics, it would be best to have a qualified electronics technician perform the repairs.

This is NOT a high-tech repair. Someone at a computer repair shop like Best Buy (Geek Squad), or a stereo or TV installation/repair shop could replace this part; although the labor to have the capacitor installed will far exceed the couple of dollars the actual component costs. If you know someone who has a teenager that knows how to solder and has built any kind of electronic kits, they can do it for you.

Please note that this looks like a large electrolytic capacitor, and it is probably polarized like a battery; so it is important to install it properly. If it is installed backwards, it could explode, splitting the metal can and spewing electrolyte (when power is applied); so extra care is warranted.

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By the way, the reason this broke off is that the component leads probably did not include stress bends between the component body and the printed circuit board.

PCB manufacturers usually either put U-shaped bends in the component leads to raise the body up off the PCBA, or mount the capacitor on its side with the legs making a 90-degree bend (straight out, then straight down into mounting holes) to take stress from vibration off the leads where they enter the body of the capacitor, and at the solder joints. The leads probably broke off at the component body due to vibration.

Alternately, the leads just go straight down through the printed circuit board (being soldered on the circuitry on the far-/under-side), with the capacitor body being tacked with hot melt glue to the pcb surface. This also takes the mechanical stress off of the leads from the body vibrating, but it doesn't relieve stress from thermal contraction/expansion caused by electrical loads and winter/summer temperature swings.

Again, this is not high tech, just basic electronics assembly techniques. Just my opinion, but the fact that this capacitor just "fell off" doesn't say much for this manufacturers solder assembly techniques.

[BDandTTs]

Thanks a lot, Phoenix. Help that's offered by people like you is why this forum is so valuable to Airstreamers.

We'll take a close look at the circuit board and the detached capacitor tomorrow, and if Bob does the repair he will take all safety precautions.

[Phoenix]

Just curious if you were able to find the replacement capacitor.

I looked at your photo again, and it looks like the two capacitors and the twin toroid coils may be in a push-pull circuit.

It's just a guess, but if you can't read the value on the side of the capacitor that broke loose, it might be the same as the one that's still mounted on the pcba. You may be able to compare the printing between the two and make an educated guess to whether they are the same part.

Please let us know if you are able to repair the converter.

By the way, I looked on the Internet for schematics, but Parallax/Magnetek doesn't publish them. Also, in this day and age, not many techs repair boards at the component level. It looks like most just swap boards now, and reading schematics may be a lost art/skill.

[BDandTTs]

Thanks again for your interest, Phoenix.

We removed the board and found that the solder on the second capacitor was also damaged, just holding on by a thread. We were not able to find a replacement locally, but were told that digikey.com would be the place to look. We also called technical support at Parallax. Although they do not repair boards, he said he would send the capacitor type/part number, but the email has not yet arrived (?).

Considering all the options, we decided to upgrade to a Xantrax 60Amp converter now instead of risking a breakdown when we are far from home. "It's only money," and a failure could damage appliances or our batteries. We ordered from Best Converters, shipping was free and it has already begun it's cross-country trip. Their website also has a very complete description of the installation of the Xantrax converter into the existing Parallax 7300 box.

[Silvertwinkie]

I really think this was your best move. I replaced my OEM converter with the WFCO conversion kit that Best Converter sells. It has three stage charging which the OEM unit did not. The Xantrax also is a three stage unit and will save your battery or batteries over time by not applying the same voltages at all times.

[CanoeStream]

Yeah Eric, I should spend some forum time on my Safari and finally replace my Parallax. Subwoofer done yet? Hah! It's a wonder why they let some people moderate at AIR...

Dianne, my capacitors are potted down in contrast to what they did with yours. My Safari was born on August 8, 2005. Please document your switchout and post it back here.

[BDandTTs]

Our trailer was manufactured in January, 2005 and the capacitor attachment is certainly weaker. Don't exactly know when the converter originated, but your attachment looks much more sturdy than ours did.

Bob investigated the DigiKey.com site and found replacement capacitors for $5 each (shipping charges extra and unknown at this time). Think we'll probably get the parts and repair the Parallax board in order to have a backup to the new Xantrex...just in case.

Any one have suggestions about what to use for potting or gluing the capacitors?

Thanks again,

[BSmiley]

Bob,

I replaced my Parallax yesterday, and will install the new AGM batteries and power up today after work. I used the excellent photo description of the replacement in our 25' Safari LS and it was an easy job. Only trouble I had was in shoving the Parallax box with the Xantrex installed inside. The screws holding the Xantrex to the side of the Parallax box didn't have clearance, but a little maneuvering, and a large screwdriver to make some temporary room made it fit. I'm excited about have a 3 stage charger.

Good luck with your installation, and repair for backup.
Barry

[Silvertwinkie]

Originally Posted by CanoeStream

Yeah Eric, I should spend some forum time on my Safari and finally replace my Parallax. Subwoofer done yet? Hah! It's a wonder why they let some people moderate at AIR...
Attachment 82857

Someone has to do it....it's always better when the inmates take over the asylum anyway.

Yea, woofer been in for a bit over two years now and though the WFCO kit is great, I just don't know if it's all that great. It works, but I get a lot of fan action. It may be because my batteries are still original, but we'll see once I replace the batteries if it's just the converter or the batteries causing the fan to go on all the time.

[Phoenix]

In the printed circuit board industry, they often use hot melt glue to stake larger components down. The regular glue sticks that they sell at home depot, Ace and Walgreens are the same as what electronics manufacturers use, except the commercial sticks usually reference commercial or military standards in their specifications.

Just clean the surfaces of the board and the components that will get glued with alcohol to remove any grease or contamination before you apply the glue. That will insure that it adheres. The glue is pretty easy to remove, so don't worry about doing a pretty job. However, the purpose is just to stabilize the part, not keep it from being yanked out; so you don't need much.

[SilverGate]

Originally Posted by BDandTTs

Considering all the options, we decided to upgrade to a Xantrax 60Amp converter now instead of risking a breakdown when we are far from home. "It's only money," and a failure could damage appliances or our batteries. We ordered from Best Converters, shipping was free and it has already begun it's cross-country trip. Their website also has a very complete description of the installation of the Xantrax converter into the existing Parallax 7300 box.

The Xantrex XADC60 amp converter is good choice. I'm happy with mine.

I posted and illustrated how I installed mine in my thread "Parallax Converter Replacement with Xantrex", in this sub-forum.

[BDandTTs]

Our new Xantrex is installed and working wonderfully. Instructions on the Best Converter site were very helpful, but it does appear that the metal boxes surrounding the converters varied from one Airstream model to another.

The Xantrex 60amp converter runs much less frequently, and is more quiet. With our 2 6V batteries and a 75Watt solar panel, we should now be set.

We have not yet ordered the part to repair the Parallax, but still might.

Thanks, everyone for your help.