Resistor replacement

[Jean Perret]

Hi folks,

I need to find a replacement capacitor for an old rc toy car 1985, the capacitor is a cylinder green ceramic refs, 47 ohm 5%, 2W, 732.

Please let me know if you have any part that could fit this.

 

[shrtrnd]

Caps are marked in micro-farads (ie: mfd, ufd, something like that). You're looking
at a green, ceramic, 47 ohm, 2W RESISTOR, with a 5% tolerance.

 

[Jean Perret]

oups.. my bad.. OK then do you have a ref or part that I can order? Funny thing is that combination 47 ohms , 2W seems strange as the resistor is quite big for its power...?

 

[jpanhalt]

How abut a picture?

John

 

[shrtrnd]

I don't know where you're at to recommend a supplier.
Do you have any electronic supply repair stores in your area?
If the values you gave are correct, you should not have a problem obtaining this
part from almost anywhere that sells electronic parts.
Your physical description has some of us wondering about this, and asking for a picture,
because green-colored cylinders are rare for resistors.
You want a '47 OHM, 2 watt, 5% tolerance resistor'. That's all you need to tell them.

 

[Jean Perret]

thank you, I will try to post a picture, usually have a hard time downloading pictures.. maybe this car being so old, 1985 makes the part kind of rare those days as a ceramic cylinder green or maybe the 2 I read with a triangle beside is a 5 reversed..

 

[shrtrnd]

If you're actually reading the marking on the component, you've probably got it right.
What worried others here, I think, is that circa 1985 components that were large and
green plastic encapsulated components, were a lot of inductors and some capacitors.
That's what made us wonder about this.
You seem certain the cylinder is ceramic, which means to me that you probably do
have a ceramic 2 watt power resistor.
I'll mention this for trivia.
I used to live in a high humidity area, but live in a desert now. I do remember in the
high humidity location, sometimes car components could turn green from organics
growing on some of the electronic components, like a ceramic resistor, because of
the high humidity. If you have a minute, out of curiosity, does this component look
like it's painted green, or could it possibly be organic growth making it look green?
If you're unsure if it's a 2W or a 5W resistor, it wouldn't hurt to buy a 5W one, they're smaller in size these days.

 

[jpanhalt]

1) Why do you think the resistor needs to be replaced?
2) Are you sure the outer coating is ceramic and not hard plastic or epoxy?
3) Is there a name on it,like "Dale" or symbol like IR?
4) What is its length and diameter?
5) I have never encountered mirror writing on any component. A picture would help explain your last sentence.

For uploading pictures, go to: go advanced>manage attachments>point to the image file on your PC>upload. Then with the cursor where you want the image, click on the attachment drop down and click on the attachment. That will enter the link to the image that you uploaded here.

John

 

[Jean Perret]

in fact this part has overheated and leaks at it's bottom.. by my stupid mistake rushing to charge the batteries on the truck using the charging port on the truck.. I say stupid because using only 4C batteries rechargeable in this case I hooked a leaf blower 18V charger gambling on the polarity..guess what...when things can go wrong they sure go wrong. Smoke! so I unplugged everything and took it apart, one wire that connects to one of the batteries overheated, and this resistor soldered to this wire also overheated and leaked at its bottom. Anyway I will try to put some pictures. The only sign I could find as a brand maybe was a triangle sign.

 

[(*steve*)]

Resistors don't "leak". You need to post a picture (I realise this request is coming late in the thread, but hey) so we don't give you poor advice.

 

[shrtrnd]

I'd like to 'third' that request for a picture if you can do it.
What caught my interest in this thread, was that I had a 1984 vehicle that had a
ceramic 'ballast resistor' in it (unglazed, basically potted with what looked like sand).
In high humidity, the thing absorbed water from the air, and the outside actually grew
green mildew on it. What typically happened over time, was that the combination of
usage and humidity would cause the thing to crack and need replacement.
I may be giving you poor advice if I'm barking up the wrong tree, thinking my issue is
similar to yours, so a picture would help clarify that.
I'm THINKING that if this case is similiar, when you overheated the component, you
could have cooked all the water out of it, making it 'leak'. But *steve*'s right, resistors
don't normally have anything in them that can 'leak'.
My curiosity about this is still perked.

 

[Jean Perret]

No the resistor is really green in color, in fact it hasn't leaked it has overheated at one of the bottom connections, a kind of melt between the board material itself and the bottom of the resistor ( was trying to charge the batteries in the truck using a to powerful charger into the onboard charging plug), brownish color, I will try to post pictures, sorry I am terrible when it comes to upload pictures...This is the truck, the yellow one http://rctoymemories.com/2012/11/04/tandy-radio-shack-4x4-off-roader-1985/

 

[(*steve*)]

Now the penny drops. The resistor is designed to limit the charging current and is going to get hot.

Your "powerful charger" is the problem. Use the supplied charger if you charge the batteries whilst in the car. If you want to use a specialist charger, take the batteries out. The resistor could quite easily fool your charger into overcharging the batteries and even if not, the extra heat is not going to help anyone.

If you want to replace it (it may be fine to use with the original charger) get a resistor that is physically as large as will fit. You'll find that they are likely to be grey or beige square prisms

Look at the picture here. On that guy's hand are two resistors like the ones I'm talking about and one metal clad resistor. The white ones are more common, and the ones with leads coming from each end are most common (they're axial as opposed to radial). The axial one is shown with little feet, these are often not present.

 

[Jean Perret]

he problem is also the very small wires running on this board.. Will not take the higher voltage load...I don't really need to charge the batteries from the truck and it would take forever so I will simply replace this transistor by the same kind and charge the batteries outside the truck.
Thanks guys!

 

[shadowfax49]

Despite requests the OP still hasn't given the physical dimensions - a big help in estimating the power rating (assuming the "2 watts" is in question).
It could be a vitreous enamelled wirewound resistor - although 2 watts is a low rating as they usually start at 5 watts and vitreous types are considerably more expensive than ceramic housed/powder filled types which is what you'd expect in a device like that.