Hello,
I am trying to repair a search light on my boat and need to replace the resistor which supplies power to the joystick (which operates the light). The resistor is a (Ph) 5W45RK but I can't find it anywhere on the internet. Is there a replacement for this one or can someone point me in the right direction?

 

Hello,
I am trying to repair a search light on my boat and need to replace the resistor which supplies power to the joystick (which operates the light). The resistor is a (Ph) 5W45RK but I can't find it anywhere on the internet. Is there a replacement for this one or can someone point me in the right direction?

Welcome to AAC!
Can you post a photo of the resistor?

Does it look anything like this?

 

Welcome to AAC!
Can you post a photo of the resistor?

Does it look anything like this?

View attachment 354869

See attached, it does look like it.

 

The wire was broke off one side of it when I saw it hanging, the other side broke off when I tried to remove it from the device.

 

The wire was broke off one side of it when I saw it hanging, the other side broke off when I tried to remove it from the device.

Try measuring with an ohmmeter on the leads that might still be remaining.

Could be 45Ω 5W.

 

As dl324 says, try to measure the resistance at where the leads broke off.
45 Ω is unusual but 47 Ω should work just as well.

https://shop.sayal.com/products/rha-47r-051

 

https://www.amazon.com/Qjaiune-Precharge-Horizontal-Resistors-Resistance/dp/B098QLDMBR/ref=sr_1_1
It's only two ohms higher, which means it will draw slightly less current to the lamp. Is the lamp an LED light?
45W ÷ 12V = 3.75 amps.
47W ÷ 12V = 3.92 amps
The difference is 17 milli-amps (0.017 amps)

 

3.92 - 3.75 = 0.17 and that is 170mA

 

https://www.amazon.com/Qjaiune-Precharge-Horizontal-Resistors-Resistance/dp/B098QLDMBR/ref=sr_1_1
It's only two ohms higher, which means it will draw slightly less current to the lamp. Is the lamp an LED light?
45W ÷ 12V = 3.75 amps.
47W ÷ 12V = 3.92 amps
The difference is 17 milli-amps (0.017 amps)

The lamp has a halogen bulb but this resistor is on the joystick side of the switch (the joystick is used to rotate the light). I will check the resistor to see how many ohms it is.

 

W = watts
use Ω or spell it out as ohms.

Use this to find special symbols:

 

You wouldnt need a resistor on the lamp itself. I missed the description of the joy stick. That's a pretty large resistor (5 watts). It may have more to do with the joystick circuitry than anything else. Pictures would be most helpful. And a good schematic if you have one.

@panic mode yes, good catch.

 

https://www.amazon.com/Qjaiune-Precharge-Horizontal-Resistors-Resistance/dp/B098QLDMBR/ref=sr_1_1
It's only two ohms higher, which means it will draw slightly less current to the lamp. Is the lamp an LED light?
45W ÷ 12V = 3.75 amps.
47W ÷ 12V = 3.92 amps
The difference is 17 milli-amps (0.017 amps)

Besides the error, the voltage across the resistor is not necessarily 12 V.
Presumably, the joystick controls a high wattage pot.

 

W = watts
use Ω or spell it out as ohms.

Use this to find special symbols:

View attachment 354881

I always wondered why a symbol that looks a bit like the Parthenon is where you find the scientific symbols. Maybe a connection to the Greek alphabet? Even so, it's a bit obscure.

 

Hi fly,
It is a 5Watt 45 Ohm resistor.
E

Using Google image search.

 

Hi fly,
It is a 5Watt 45 Ohm resistor.
E

Using Google image search.

Thanks for all the help guys, I will let you know if I get the device to work after replacing the resistor.

 

Gracias a todos por su ayuda, les avisaré si logro que el dispositivo funcione después de reemplazar la resistencia.
[/CITA]
Tengo el mismo detalle el resistor se me rompió y lo necesito reemplazar, que medida usaste y te funcionó?

Mod: translated.
Thanks everyone for your help. I'll let you know if I get the device working after replacing the resistor.

I have the same problem; my resistor broke and I need to replace it. What size resistor did you use, and did it work for you?

 

If the resistor is part of the motor control scheme then it is there to slow the motor a bit. NOT in series with the light. So slowing the motor a small bit more is not going to be a big deal.
I suggest getting a different style of resistor that will be more durable. That one was obviously the cheapest one that could work. One of the brown ones with connection lugs will be far more durable and probably run a bit cooler. And a ten watt rated resistor will give a bit of safety margin if the motor ever stalls, or if it is operated a lot.