:On 19/10/2010 1:40 PM, kreed wrote: :> On Oct 19, 10:51 am, Sylvia Else wrote: :>> On 19/10/2010 1:13 AM, kreed wrote: :>>
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:>>> On Oct 18, 11:57 pm, F Murtz wrote: :>>>> kreed wrote: :>>>>> On Oct 17, 2:51 pm, Sylvia Else wrote: :>>>>>> On 17/10/2010 2:49 PM, Metro wrote: :>>
:>>>>>>>> OK, since Phil can't, perhaps you'd care to explain why shorting of poorly :>>>>>>>> insulated wires either to each other, or to the underside of the circuit :>>>>>>>> board, is not an issue. :>>
:>>>>>>>> Sylvia. :>>
:>>>>>>> The ' poorly insulated wires ' have nothing to do with the failure. How :>>>>>>> would they be shorting? How would they short to the ' underside of the :>>>>>>> circuit board '? It would be physically impossible without tampering :>>
:>>>>>> Because of the position of the insulating sleeve on the uppermost wire, :>>>>>> it can short to its adjacent wire which has no insulation. In the second :>>>>>> picture, the two wires can be seen to be touching just to the right of :>>>>>> the platic base fo which the tube is attached. As I've indicated, the :>>>>>> wires themselves are either not insulated at all, or the insulation is :>>>>>> poor, because I can make contact along their length using multimeter probes. :>>
:>>>>>> When the lamp is assembled the wires lie along the back of the circuit :>>>>>> board. Where the wires have no insulating sleeve, they can make contact :>>>>>> with the circuit tracks and component leads on the back of the board. :>>>>>> The lower three wires can all make contact with something they should :>>>>>> not on the back of the circuit board adjacent to the connecting pins. :>>
:>>>>>> Sylvia. :>>
:>>>>> Are they enamelled copper wire ? :>>
:>>>> If it is enameled it can not be any good as Sylvia made contact along :>>>> wire with the meter probes :>>
:>>>>> That should be able to cope with any voltages present in that :>>>>> circuit ? :>>
:>>>>> That spaghetti over the top would mostly be for protection from heat ? :>>
:>>> I wonder how good the enamelled wire is in the transformer then ? :>>> Might be worth looking at, but also might not be from the same :>>> supplier. :>>
:>> An earlier post indicated that the wire leading to the tube is a special :>> alloy to handle the high temperatures associated with being inserted :>> into the molten glass during the tube manufacture. I haven't checked, :>> but it seems plausible. If that's the case, the the transformer won't :>> use the same wire. :>>
:>> Sylvia. :>
:> Unless there is obvious damage to the circuitry such as a violently :> blown fuse, or burnt, damaged components, :> you could try to wire a regular fluro tube to the PCB and see if it :> lights. : :I've determined that one of the heater elements is open circuit. This :wouldn't happen as a result of the two wires shorting together, but it :could happen as a result of the uninsulated wire touching something on :the circuit board that it shouldn't. : :> This would indicate whether or not the circuitry is still operating, :> or was damaged. :> If there was a short from that wire to the board, there would be a :> good chance of damage to the circuitry. :>
:> I have since dismantled several failed CFL (various brands with date :> of purchase going back as far as 2002), :> All have that same type of woven (heat resistant) sleeving over the :> leads, :> In many cases the wires in those sleeves are bare :> In all cases they had an open circuit filament which was likely the :> reason for failure. :>
:> One Philips CFL had a different design to yours, an extremely compact :> plastic base, the PCB was mounted upside down (solder side of the PCB :> facing the tube) with 2 cutouts in the PCB's for where the tube ends :> come through the base. How they fit all the circuitry :> on the remaining board space was remarkable. :>
: :Sounds like the more recent one I diassembled for comparison. The :significant difference from the failed one, apart from all the wires :being insulated, is that the insulation was about as long is it could :be, rather than only 2/3 the length of the wire it was insulating. : :The board had a rather strange shape - one which I suspect was designed :to allow a denser use of the manufactred boards, albeit at the cost :having curved cuts. : :Sylvia.
This CFL looks like the Philips Genie 14W model. I recently pulled one apart when it suddenly stopped working. On mine all 4 wires from the filaments were insulated with fibreglass spaghetti. No, they are not enamel insulated wires because they are simply wrapped around the square terminal posts and there was no evidence of any enamel insulation having been removed either. I tested every component on the board and couldn't detect which part had failed. Both filaments were ok and there was absolutely no evidence of any shorting on the pcb. The inside bottom of the tubes adjacent to the filaments were devoid of phosphor coating though.
Pavouk has gone to the trouble of posting schematics of a few brands and models of CFL