Repair Sylvania Model 72032 LED Lite?

Franc,

These are the results

Zener markings I could see N1 & A

power off R series resistor ~22M Ohms

Zener Test with Ohmmeter of Multimeter

Negative Probe on Cathode (Black Strip) ~140 K Ohms

Positive Probe on Cathode (Black Strip) ~167 K Ohms

power on

Vin ~111 V

Vout to 0 V ~200 mV

"If the diode is reading a much lower voltage than its rated voltage, such as near 0V"

From tests seems Zener is Shorted.

Since the zener was destroyed from a "power surge" what upgrade do you suggest to prevent this from happening?

Ken

"The battery appears to have three cells. Is it a 3.6V type? Does it have a mAH rating on the body?"

Was finally able to locate this LED Lite on the OEMs website.

It is listed as Model 33030008A

Bat info Ni-MH 3.6V 110 AH

Ken

Mikek & Everyone,

"I have the same light, if you find a good battery for replacement, please post it. I need three!"

I would like to convert them to rechargeable Li if possible.

Did a quick search and found

Any suggestions concerning what is the best for LED lites and what is needed to convert this Ni-MH Lite to Li?

Thanks

Ken

On Tue, 27 Nov 2012 07:29:51 -0800 (PST), KenO put finger to keyboard and composed:

Sorry, I can't make anything out of that.

It looks like this is open circuit.

I'm not sure what you are doing here. You should connect one probe to one end of the zener, and the other probe to the other end. If that's what you were doing, then you should have used the diode test function of your meter.

This is consistent with an open circuited series resistor. The zener is not shorted, as per your previous measurement.

That said, I'm surprised that Vin is so high. I can't imagine that the zener voltage would be more than 10V, so this would mean that the series resistor would need to drop a lot of voltage. It seems too small for that kind of wattage. Something doesn't look right to me, but I can't see the circuit clearly enough (too many components obscuring the PCB). I don't think I can help you without a circuit diagram.

- Franc Zabkar

On Thu, 29 Nov 2012 21:51:12 +1100, Franc Zabkar put finger to keyboard and composed:

I'm wondering if there may be a series capacitor whose function it is to losslessly reduce the supply voltage ... C2 bridge 1uF rectifier 250VAC ______ | | Vin AC1 o--| |----| |----o-- R --+----+---o Vout | | | | | | ||>| | ZD1 C | | | | AC2 o--| |-----------o-------+----+---o |----| 0V

As for the zener voltage, perhaps we can guess at its value by examining the battery charging circuit.

D1 100 ohm Vout o---|>|---- R4 ----+-o | 3.6V NiMH 110mAH battery |

If we assume that the charging current is 11mA (mAH rating / 10), and if we allow for a charging voltage of 4.5V, say, then Vout would be ...

- Franc Zabkar

On Fri, 30 Nov 2012 17:10:41 +1100, Franc Zabkar put finger to keyboard and composed:

Sorry, C2 should be on the AC side of the bridge, not the DC side.

- Franc Zabkar

Franc,

"It looks like this is open circuit. Zener Test with Ohmmeter of Multimeter Negative Probe on Cathode (Black Strip) ~140 K Ohms Positive Probe on Cathode (Black Strip) ~167 K Ohms I'm not sure what you are doing here. You should connect one probe to one end of the zener, and the other probe to the other end. If that's what you were doing, then you should have used the diode test function of your meter. power on Vin ~111 V Vout to 0 V ~200 mV

Redid the tests using the diode test function of the meter and got the same results.