The LED panel on my cooker has failed, the module appears to control the functions OK, but the clock display is not illuminating, I have done some searching on the web, but am not happy to part with £40 for a exchange module, on examination it is only the LED module that has failed, it is one of the large glass encased types, but cannot source the parts, if anyone can help it would be really appreciated. Its a belling cooker, and I think the timer module is part no. 316 T85 (a four wire module, mains in, and a switched pair) manufacturers are hopeless, quoting in excess of £120!!!! any help or suggestions, greatly appreciated, Karl.

 

Are you sure it's LED?, as you say 'glass enclosed', that sounds more like a flourescent display module. If so, the most common problem is failure of the heater supply to it (it's essentially a valve), often dry joints, or a capacitor which couples the AC to it.

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Hi there Nigel, and thanks for the responce, I will pull the module again later and check it out, I am assuming it's a simple fault because, apart from the controller chip, there are barely a handfull of additional components, one of which is a mains coupled cap, will update after further investigation, Karl.

 

While you are there post a picture (front and back) of the display and the model number for the cooker. You may get lucky.

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I have had another look, the board is manufactured by Invensys, model no.D78559, have looked at your sugggestion and checked all for dry joints etc, has all now been re-soldered, but still no signs of life. Have included pics of the module if it helps. One thing I have noticed in pic2, at the top left of the display is a piece of metal inside the display that appears to be bent, it looks worse when you have module in your hand, I have turned up the contrast a bit to try to get more detail. As I said before, the timer circuit still appears to work and control the oven, its just the display side, Karl.

Attached Thumbnails

       

 

Yes, that's a vacuum flourescent display it should have a low AC voltage feeding the heaters (the outside pairs of pins at each end).

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do you know what voltage levels I should be looking for?

 

It's usually something like 3V AC, but often DC shifted from ground, commonly negative.

There looks to be VERY few components on that board!.

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thats what makes it more interesting, there's virtualy nothing on the board to go wrong!!

 

A VFD display when working should show very faint orange filament wires.

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Hi,
Photo's 1 & 2 clearly show that the heater elements are broken.

You need a new display.

 

yes, I see it, have spent last hour and a half online trying to source one, no luck, anyone any ideas?

 

They are often made to order.

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Smart Kits build Smart People
http://www.blueroomelectronics.com/

 

Could be the best bet is to pay the £40 for the exchange module and be happy that you could get it at all.

__________________
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BCHS/3v0's Tutorials
Junebug USB PIC programmer kit., USB Bit Whacker,
The 15 Minute Printed Circuit Board! (+drill time)

 

Looks like you may be right, ah well was worth a try, and thanks again to everyone for the help and advice, greatly apppreciated. Karl.