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Discussion Starter #1 (Edited)
I'm lighting my 1/350 PL Refit - I'm using CCFT's in each nacelle - each with it's own inverter. When I hook up both to my Radio Shack 12V 1.5amp power supply, one dims.

If I hook up each one by itself, both are fine. The problem seems to be with the right one - I'm wondering if a bad solder connection at the inverter circuit board would do this. I removed the wires from the inverters and directly soldered the leads from the tubes to the board - did the same with the power leads to minimize wire length.

I also had to replace one of the inverters because it died. I don't know if the new one is the problem or if the dim nacelle is the old inverter.

I am running the full 12V (really close to 15V...) using 18 gauge wire right to the nacelles (I've isolated them from the rest of the model for testing) -

Everything else is working great. When I hook up everything (the saucer, etc), one nacelle lights brightly and the other is dim. (That's when I decided to isolate them to narrow down the issue.)

I should have plenty of power to run these things. Any suggestions? Wild guesses?

One thing is for sure. They are gonna be a pain to crack open again - I epoxied those mothers!
 

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Most of my electrical experience comes from my days as an aviation electrician in the Navy. From reading your problem, I would say that there could be any number of culprits. For instance, if the wires going to your poorly lit nacelle are only half connected, like if one of the wires was almost completely cut, but has one or two strands that still have continuity, enough to carry the voltage, but not the current, then it could dim and not affect your other nacelle. You could try to hook your nacelles up in series instead of parallel and see if they BOTH dim. If you had a bad solder joint, then I would say that it would be dim whether you hooked them both up at the same time or individually, so I don not think it's a bad solder job. It's possible that you have a bad inverter. It may have been fried if the amps from your power source are too high. It runs fine by itself, but with the increased load from the rest of the ship or the slightest load from just the other nacelle, it dims. That's what I'd bet on. Just MHO. Hope I could be of use. If you want to avoid having to tear open your nacelle, and it works fine hooked up by itself, I would hookup a separate power source. You could install a nine volt battery in the base to run just that nacelle. Just an option to avoid possibly ruining your assembled nacelle.
 

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Discussion Starter #3
zenomorp said:
Most of my electrical experience comes from my days as an aviation electrician in the Navy. From reading your problem, I would say that there could be any number of culprits. For instance, if the wires going to your poorly lit nacelle are only half connected, like if one of the wires was almost completely cut, but has one or two strands that still have continuity, enough to carry the voltage, but not the current, then it could dim and not affect your other nacelle. You could try to hook your nacelles up in series instead of parallel and see if they BOTH dim. If you had a bad solder joint, then I would say that it would be dim whether you hooked them both up at the same time or individually, so I don not think it's a bad solder job. It's possible that you have a bad inverter. It may have been fried if the amps from your power source are too high. It runs fine by itself, but with the increased load from the rest of the ship or the slightest load from just the other nacelle, it dims. That's what I'd bet on. Just MHO. Hope I could be of use. If you want to avoid having to tear open your nacelle, and it works fine hooked up by itself, I would hookup a separate power source. You could install a nine volt battery in the base to run just that nacelle. Just an option to avoid possibly ruining your assembled nacelle.
Thanks, Zeno ! I already tore that sucker apart. I already had one bad inverter so I'm going to buy another one just to rule it out - they are only 9 bucks. If that doesn't change anything I'll replace the tube too.

There ain't much left after that - other than checking the solder joints - I'm using a common ground so that could be it too. If I figure it out, I'll post it for future reference.

Anyone else have a similar problem?
 

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Try hooking an ammeter (amp-meter) in series with each of the inverters. Since each works okay individually, we can rule out bad inverters and bad tubes. The current draw for each of the inverters should be about the same. If not, look for why not.
 

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If one of the tubes is dimming when they are together but both are bright separately, this usually indicates that you don't have enough power. My Refit is drawing over 2.3 amps.

I see that you mesured your supply voltage at 15V. Was that while it was driving the model? If not, check it while it's driving your model.

The 18 awg wire should be good. It is unlikely that a solder joint is causing your problem.

Where are the inverters located?

Let's see if we can nail this down for you.
 

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Discussion Starter #6
Thanks, Pat. I measured the voltage with no load.

The inverters are right in the nose of the nacelle. I would think that 1.5 amps would be plenty to drive just the two ccft's (I hooked them up separate from the rest of the model to test. Maybe not....
 

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Discussion Starter #7
jwrjr said:
Try hooking an ammeter (amp-meter) in series with each of the inverters. Since each works okay individually, we can rule out bad inverters and bad tubes. The current draw for each of the inverters should be about the same. If not, look for why not.
Pardon my ignorance but how would I hook up the ammeter - would it be

battery (+) > ammeter (+) > inverter (+)
inverter (-) > ammeter (-) > battery (-)
 

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You will need to measure the voltage with a full load.

Your power supply may not be putting out what you think it is. Let's check it with a full load.

If the voltage drops significantly, you know automatically your current output is insufficient.
 

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Discussion Starter #9
Well, I think this ship is dead. I went out to do some testing and discovered that the nacelle that was working fine last night is dead this morning. Cracked it open and it appears the inverter is dead. Plus I broke off the pegs that hold the support to the nacelle.

Thank you all for your help and support. I give up. The refit has beaten me. I see no way to attach the nacelle without the pegs. It seems the best way to go for lighting these engines is to use a light box and strip of LEDs.

I'm temped to buy another kit and start over using the knowledge I've gained on this one. There are so many things I'd do differently - plus I still have a nifty Pat Floyd circuit board that works really well.

There have been other issues with this build too that might warrant a new start. It's just not going to come together right (plus the wiring is truly a mess - functional but not very elegant.

How many of you have started over?
 

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I have started over with numerous kits... not the refit (yet).

Part of your issue is the CCFTs. If you are burning up the converters, you probably have to put a load resistor in series with the tube... one of those things that isn't always mentioned. Don't be so quick to abandon the aproach.

Diffusing a series of LEDs has its own set of problems... I have 24 in each warp engine and diffusing it so I don't have any hot spots has proven to be a real challenge.

There's nothing wrong with starting over. It's better to start over than to keep going on a project you are dissatisfied with.

Take a deep breath. Open up the new box and dive in. You'll feel much better once you get started again.
 

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Discussion Starter #11 (Edited)
PatFloyd said:
I have started over with numerous kits... not the refit (yet).

Part of your issue is the CCFTs. If you are burning up the converters, you probably have to put a load resistor in series with the tube... one of those things that isn't always mentioned. Don't be so quick to abandon the aproach.

Diffusing a series of LEDs has its own set of problems... I have 24 in each warp engine and diffusing it so I don't have any hot spots has proven to be a real challenge.

There's nothing wrong with starting over. It's better to start over than to keep going on a project you are dissatisfied with.

Take a deep breath. Open up the new box and dive in. You'll feel much better once you get started again.
I was thinking the same thing - I need to make sure the voltage going in is no more than 12V. The manufacturer says they draw .08 amps. Seems low to me. I would guess that if the power supply is putting out 14-15V and I hook it right up to the inverter, that would cause all sorts of issues. (duh....)

I like the idea of using LED's - just from a simplicity standpoint - they draw less amps and are cheaper too.

I just hate sloppy stuff. I recently built a 64 Corvette (not a model, a real one!) and ended up doing many parts of the process twice (like the wiring!) Not because it didn't work but because it was sloppy. I even put it on a new chassis! Now the car is pristine.

My refit should be too. I'm headed off to the Hobby Store to see if they have one in stock. I hope I can find a few more boxes of holiday lights!

I should be able to re-use quite a bit of the dead ship. We'll see.
 

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The nacelle pins are an easy fix. Take a pylon that has pins on it to the hobby shop. Match up the diameter of the pin to some Plastruct or Evergreen plastic rod. Take a dremel and drill out where the pin used to be and insert a lenght of rod. Make sure you drill at the right angle. Use liquid cement to set the pin and attach the nacelle to get the right angle while the glue sets. I did this for one of my pins.
 

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In hooking up an ammeter you would normally put the positive (red) lead towards the power supply and the negative lead to the load. But if you are using a digital meter, it will probably not matter. If you hook a digital meter up backwards, it will read a negative number for the current. No biggie.
Insufficient current would certainly cause dimming, but wouldn't it cause dimming to BOTH CCFLs?
I don't know if 1.5 amps will be enough for the entire refit (mine draws a bit over 2 amps), but it should certainly be enough for 2 CCFL inverters.
 

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Discussion Starter #14
Well, just got back from the hobby store with a fresh refit kit. I have lost my mind. Back to the drawing board.....
 

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Discussion Starter #18
1711rob said:
hey i broke mine off too BUT still finished it, thanks to some super glue and some j b weld.If you dot look too close you dont notice the flaws with that

http://s77.photobucket.com/albums/j54/1711rob/

I wanted to give up too but i didnt and am now getting ready to strat #2
If that was the only issue, I'd probably fix it. However, there is so much I want to do differently - starting over is a good idea. I can probably reuse much of the LED's and such. I want to affix them differently - plus, I need to do a better job of light blocking.

I will also use better, brighter LED's to reduce the number of LED's. I have also learned the technique of hitting the LED's with sandpaper to diffuse them. Pat just told me about some large, blue diffused LED's that sound perfect for nacelles.

Also want to diffuse the clear parts for better illumination. The weird thing is that the new kit is made of light blue plastic instead of white!

I also want to better detail and light the shuttle bay, arboretum and VIP Lounge. Plus, there is the detailing on the impulse drive that I didn't know about....

I could go on but you get the picture.

One question - do you guys shoot primer on the interior before the light blocking paint?
 

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thrakkorzog said:
Parallel.
If that's the case and both ccft's are the same specs(and no resistors tucked away anywhere along the wiring of one and not the other?) I have no explaination other then perhaps one of the CCFT's is simply defective.

It's rare but it happens.

Buy a couple more with the same exact specs and chances are you'll come up with a matching pair, unless the problem was non-identical specs/wiring.
 

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thrakkorzog said:
Well, just got back from the hobby store with a fresh refit kit. I have lost my mind. Back to the drawing board.....

Save the previous kit for spares, conversions and bashes.
Please do consider using EL materails like Lightsheet. Works at about 6 volts. That stuff draws a lot less power,and very OK when hooked up in paralle...Like this stuff from Miller Engineering: http://www.microstru.com/Experimenter-Kits.html


Good LucK!


DLM
 
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