Rayline Searchlight on fritz...Need electronic expertise

[MikeP]

Last year I completely overhauled my 10" 32V Rayline searchlight and it has been working fine until yesterday. Now the light illuminates but there is no motor movement at all. I pulled it off and did some checks. Each of the two motors will operate perfectly if 12V is applied directly to their terminals, leading me to believe that either there is some sort of wiring/connector problem or the voltage regulator board is bad. I checked the wiring and connectors and all seems OK.

What follows is based on the fact that I am NOT an electronics person. I can assemble and solder quite well but I have no training or understanding of the electronic circuits beyond an EXTREMELY basic level (if that).

The board (see pic) has several components that I can identify: the transister, the brown wire-wound resister, the 25W heat-sinked resistor, and three components that look to me like diodes. But I'm not sure that's what they ALL are. In checking them, two of them act like diodes (Green arrows) - they pass voltage in one direction but not the other. The third one (red arrow) will pass some voltage in both directions but not the same amount. If it's a diode, then it shouldn't do that. But is it a diode or is it possible that it's a capicitor? The lettering on the component is a "B" and then below that, "C804." NOTE:I'm checking the components as mounted in the circuit-not disconnected. Will this invalidate the measurements? The resistors measurements are as per their markings. The transistor will also pass (or not) voltage between Collector, Emitter, and Base as it should.

Any ideas? I know I can send the board to Jabsco; I'd rather sort it out myself but I don't care to start studying electronic circuits!

Thanks!!

[TedZ]

Wow!

To start simply, diodes do pass some voltage in both directions, i.e. they are not perfect. It should be more one way than the other but don't forget the tiny voltage your meter is providing in continuity check mode may not be large enough to check diodes reliably. Better meters have a diode check mode.

Is the board you have in the picture a voltage regulator board? 32 VDC to 12VDC...is that what you're thinking? I couldn't quite read the writing on the heat sunk component (looking at my laptop upside down :-) but that is an unusual resistor...marine use maybe...looks like it says 25W which would be consistent with a large resistor...so maybe.

Trouble shooting this should be easy. Start with your control switch...make sure it is getting 32VDC if that is the supply voltage. Check that is it feed forwarding in all of the switch positions. Go to the light and check input voltage while someone moves the switches. If there is nothing going on in the motor feeds look for opens...the resistors (the wire would being no 1 on my list) and then check the diodes for voltage at one end and none at the other. (BTW there are no capacitors shown which is odd as usually motor windings have a cap to ground) If there is no 32 VDC going into the diodes suspect resistors strongly or wiring to the regulator.

What bothers me is there has got to be a an area where more wires are connected. Does that have circuitry, relays etc?

Sorry to ramble but trouble shooting stuff like this involves a lot of "impressions" and then you chase them down.

Ted

[TedZ]

BTW naturally you should look for the simple things first BUT if you have had an electronic failure the only devides there that should be subject to working one day and not the next are the current limiting devices, the resistors as they are doing a lot (wire wound and heat sunk) and they are easy to check for opens.

Ted

[Beckytek]

The red arrow component looks like a diode. It may not read properly in the circuit. Lift one end off (unsolder it) and then check it. You say it has a designation on the board "C804", that is the usual marking for a capacitor. If it is you should read infinite resistance out of circuit. A diode usually has numbers on it like 1n4001, a capacitor may have 2 numbers for mfd and a v for voltage. After saying all that it is pretty rare for these to go bad. I would check swithes and connections first. sometimes a wire that flexes will break inside the insulation and all looks good. If you stretch the wires at flex points by pulling at either side and the wire stretches you know its bad. If you have a schematic that would be helpful. good luck. Ron

[Trojan]

You said that the motors work when you apply 12v manually. You also said that your voltage is 32v feeding the unit. The first thing I would do is take a voltage reading on the board. Operate the controls and see what happens to the voltage at each point. Write the findings down for each point so you can compare when you work the controls. I would guess that the 2 diodes that pass are zener diodes. Used to control and limit the voltage from 32v to 12v. If you have 12v motors something must reduce that 32v. The picture is a little hard to see any id of the parts. Just guessing the red wire is 32v to the ziener reducing the voltage to maybe 14v to the a current limit resister( wire wound with a large heat sink. It should be hot in operation That is why it has the large metal case) to a pass transistor to a direction diode. The other diode is a 12v zener. The yellow wire should be 12v. The blue looks like maybe a ground or to the switch for low voltage control. The light will draw more current then the motors and is probably 32v. NOTE: just a guess I don't know how the light is wired. Check the voltage first.



BILL

[MikeP]

Thanks!

Per Jabsco, the board is a 32 to 12V voltage regulator. The bulb in the light is 32V while the motors are 12v. There is a relay for 32V bulb power in the searchlight head. The control heads for the searchlights contain 12V relays (4) to supply the voltage to the motors depending on where the joystick is moved.

I rechecked all wires and connectors this morning between helm and the searchlight mount with a multimeter. They are all OK. I suppose that the control heads could have a problem but there are two - helm and flybridge - and they both produce the same results, light but no movement.

My multimeter has a diode test position and two of them that I've checked in the circuit show about 0.5 volts in one direction, none in the other. The questionable one (diode or capacitor?) shows around 0.4V in one direction, 0.9V in the other. But again, this is checking with everything in the circuit.

I would like to be able to hook it up again and measure the voltages at the board but I have to find some help since I can't operate the control head and measure voltage supplied to the light's circuit board at the same time- THe Admiral's out of town.

It appears that 12V is not getting back to the control heads. I opened one of the control heads. There are 4 12v relays - one wired to each direction that the joystick can move. They are in clear plastic cases and they don't seem to energize regardless of joystick movement. There is a very faint click from the control unit if the joystick is moved but it doesn't have that positive snapping CLICK that relays usually do and I can't see any of the relay contacts moving.

[Trojan]

You would not likely have a cap in a dc motor control. The brown resistor is a feedback voltage to stabilize the control. You don't say where the wires are going. What is the number on the control transistors?



BILL

[MikeP]

The transister is labeled "MJE2801"
the resister with a heat sink is labeled "DALE RH-25 25W 5[ohm symbol] 1%"
The wire wound is labeled: "OHMITE B5J180

I get 5 ohms measuring the resistance of the big resistor
and 181.6 ohms measuring the wire wound

Attached is the wiring diagram that came with the Hatt paperwork. It certainly doesn't look like a typical Hatt-supplied doc but it was included with the hatt-blueprints on the searchlight.

I noticed that on the diagram there are 5 components; on the actual board, there are 6.

[Trojan]

Check the joy stick connections. Mine were just slip on over brass studs. The connector lost its gripping power and just slipped off. The one on the bridge would not move right or left.. The one on the lower helm would not move up or down. I just crimped the connector a bit and pushed them back on. The previous owner said its been that way for 2 years. The joysticks are really cheaply made.



BILL

[Genesis]

The component with the red arrow is a diode, BUT you can't check them in-circuit - you have to lift one end otherwise you're likely to see bad results. It should pass current in only one direction.

At least one of the diodes is almost certainly there to protect either the transistor or relay contacts - when a motor has current turned off it generates a large spike on the supply lines. Ditto for relay coils. Without the diode to snub it a transistor will be destroyed by this back-EMF surge. Relay contacts arc significantly as well and the diode also snubs that.

What I would do is trace it backwards - find the leads going to the motor and check for voltage when the stick is moved. In most cases where nothing works the problem is a bad ground because that's the one circuit that affects all directions and motors, but not always.