Wall oven control knob backlight repair

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#2027861 3-Jun-2018 16:53

Would two of these be suitable replacements - NE2 Neon indicator bulb ?

https://www.jaycar.co.nz/90v-ne2-neon/p/SL2690

These require a resistor for 230V operation. What would be the resistor considerations given each light unit has another light unit in series on the circuit.

wazzageek

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#2027864 3-Jun-2018 17:03

That's convincingly blown! Looks like a bit of heat coming off the bulbs too. G9 bulbs are 240V - but I suspect that those bulbs are either way too bright, or possibly too big to place inside the unit.

Would it be possible to place a bulb within the control area (anywhere) to supply light to sufficiently backlight the control panel, or is it specifically designed to require the bulbs to be where they are now?

For a replacement bulb, you might want to consider the longevity of the bulb (once every 18 years would be OK, once every 18 days could be a pita)

As an alternative - can you replace the "panel" with something that has the labels on it so that the backlit requirement is gone?

Fred99

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#2027872 3-Jun-2018 17:09

See this thread.

Looks like the same unit.

Personally, I'd have just used the "wedge" bulbs I linked to, and soldered the leads to extend them if needed.

In that thread, they appeared to be 12v 3W - not 2W. they seem to be available from 1w up. Most are 12v, but there are 6 and 24v.

stuartmac

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#2027880 3-Jun-2018 17:29

Fred99:

See this thread.

Looks like the same unit.

Personally, I'd have just used the "wedge" bulbs I linked to, and soldered the leads to extend them if needed.

In that thread, they appeared to be 12v 3W - not 2W. they seem to be available from 1w up. Most are 12v, but there are 6 and 24v.

Exactly the same problem. The markings on the plastic light unit itself say "RS", "1515 022", "12V 3W", "T 120 degrees C" and "PBT". So I think that is where that thread is getting that information from. However I have measured and it is 230V and I believe the wiring diagram at 2W. The plastic units might have designed for 12V 3W but that is not what Westinghouse put in them.

The thread does not report the solution worked - if I am right a 12V automotive bulb would have had a quick death.

andrewNZ

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#2027883 3-Jun-2018 17:36

The "ballast" unit may have failed causing the issue. I'd be wary of leaving the ballast installed if I couldn't find specs for it.

stuartmac

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#2027887 3-Jun-2018 17:47

andrewNZ: The "ballast" unit may have failed causing the issue. I'd be wary of leaving the ballast installed if I couldn't find specs for it.

I swapped two light units, as I have a double oven. Each oven has a separate ballast with two light units on each circuit. The problem moved from the upper oven to the lower, and the upper oven is now ok. So I do not believe it is a failed ballast.

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Fred99

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#2027888 3-Jun-2018 17:48

andrewNZ: The "ballast" unit may have failed causing the issue. I'd be wary of leaving the ballast installed if I couldn't find specs for it.

Yeah - but what is the "ballast"?

If it's (possibly) just a resistor to drop voltage to the lamps then with no load, that might explain the OP's 230V reading.

stuartmac

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#2027892 3-Jun-2018 17:56

Fred99:

andrewNZ: The "ballast" unit may have failed causing the issue. I'd be wary of leaving the ballast installed if I couldn't find specs for it.

Yeah - but what is the "ballast"?

If it's (possibly) just a resistor to drop voltage to the lamps then with no load, that might explain the OP's 230V reading.

Fair enough. I messaged hvshel to see if he found a resolution.

I am starting to wonder if the reason replacement parts are not available is that Westinghouse have had second thoughts on the design.

Aredwood

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#2027893 3-Jun-2018 17:57

Since you have a working module. Switch it on and measure the voltage across the ballast and the light bulbs.

Although I agree with the above idea of replacing them with neon lights. As Jaycar sell green and blue neon lamps. Some circuit modification will be needed. But simple to do.

Fred99

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#2027894 3-Jun-2018 17:59

stuartmac:

Fred99:

See this thread.

Looks like the same unit.

Personally, I'd have just used the "wedge" bulbs I linked to, and soldered the leads to extend them if needed.

In that thread, they appeared to be 12v 3W - not 2W. they seem to be available from 1w up. Most are 12v, but there are 6 and 24v.

Exactly the same problem. The markings on the plastic light unit itself say "RS", "1515 022", "12V 3W", "T 120 degrees C" and "PBT". So I think that is where that thread is getting that information from. However I have measured and it is 230V and I believe the wiring diagram at 2W. The plastic units might have designed for 12V 3W but that is not what Westinghouse put in them.

The thread does not report the solution worked - if I am right a 12V automotive bulb would have had a quick death.

If you can do it safely, measure the voltage across the lamps in the working unit when they're on. That should tell you approx what voltage wedge bulbs you need.

Edit : snap with Ardwood above. I'm not sure though if the small neon lights would be bright enough - compared to a 2w incandescent.

stuartmac

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#2027896 3-Jun-2018 18:16

Aredwood: Since you have a working module. Switch it on and measure the voltage across the ballast and the light bulbs.

Although I agree with the above idea of replacing them with neon lights. As Jaycar sell green and blue neon lamps. Some circuit modification will be needed. But simple to do.

OK. That means pulling the oven out again unfortunately which I am not sure I am up for again this weekend.

These are the two "ballast" units, which I am also puzzled about;

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Aredwood

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#2027917 3-Jun-2018 18:21

Those ballasts look like wirewound resistors.

linw

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#2027921 3-Jun-2018 19:08

I think recall those little 230v 'bulbs' being called peanut bulbs?

The ballast will be to stop the current surge on startup when the element is cold.

I'm sure there is a way - good luck.

linw

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#2027942 3-Jun-2018 19:31

Second drawer I tried I found a couple of neons (I think)! Really can't say what they were taken out of, or what voltage these ones were designed for, but they look like the Jaycar ones.

Agree with stuartmac, above, the ballast will be to stop the current rush when the light/bulb is cold.

sparkz25

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#2027968 3-Jun-2018 21:01

Aredwood: Those ballasts look like wirewound resistors.

i agree on this,

have you tried calling smiths? as they have a lot of spare parts for most ovens, get the model number, call them and see if they have a exploded view diagram and a parts list.

i have used them for years and they supply most of the wholesalers for parts

https://www.smithsnz.co.nz/

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