dodgy quartet's

[chrispietharding]

At our school we have 6 strand quartets. With four of them they only sometimes work, you focus them and they work fine but then when you turn them on again they don't work. But when you adjust the focus they light up again.

 

Just before my A level performance one blew a lamp. Looking at the pins on the blown lamp, one is almost black. It looks like a dodgy lamp holder? does this sound about right?

 

Cheers

Chris

[Brian]

...It looks like a dodgy lamp holder? does this sound about right?

Yes, classic sign of a failed lamp holder.

[chrispietharding]

Yes, classic sign of a failed lamp holder.

 

Righto- Thanks I'll let drama know that thats the problem and that they need fixing

 

Thanks!! :D

 

Cheers

Chris

[Dmills]

Note that this sort of rot tends to spread if you move bulbs between lanterns.

You need to replace the lamp socket AND the bulb (and throw out the damaged bubbles).

 

BTDT (I had half a dozen Cadenza F which all ended up exhibiting this exact fault).

 

Regards, Dan.

[Pete]

If its not the lamp holder it will (might) be the terminal block in the handle.

 

And be careful when taking the unit apart, I snapped one (And I'm no iron man)

 

Pete

[svincent]

I had the same sort of problem with CCT minuette's I just replaced the lamp holder and everything was fine. I think its just one of those things thats comes with age and freq useage of the lantern. their not a massive pain to replace but its a little fiddily for me as I have quite large fingers (I also have to use a pen or my letherman to address scrollers)

[Russ83]

Sorry to drag up an old thread but I didn't see the point on starting a new one on the same topic!

 

One of our drama studios that was a complete new build back in 2002 as was fitted mainly with Strand Quartets (PCs, Fresnel's and Zooms) and a few Selecon floods. The room has central heating so never gets very cold or damp and apart from replacing the gels every year and lamps when needed the fixtures don't get touched or bashed around.

 

Over the last year there have been two failures with the lamp bases (pins burnt away) and by the sound of the buzzing a few more are on the way out.

 

Because of the circumstances I want to know what could have caused this to happen? The dimmers are left on 24/7 so the pre-heat on the BetapackII's should rule out any dampness and prior to this lamp life has never been a problem. Is it impurities in the contacts that react and form a gap thus allowing arching to start?

 

The ancient Furse fixtures (oval ones) that I want to blow up show no signs of any problem although they are on a P28 lamp base.

 

Does anyone have any ideas on this?

 

The second point is obviously how to go about getting them fixed. If it was just the two fixtures I am quite capable of fitting new bases but these are Quartets we're talking about!!

I am more inclined to get the installers back in and test the whole rig of 24 fixtures, sockets, patchbay and dimmers. Is this a case or just repairing the know problem or finding what is causing it?

 

Hope that makes sense and thankyou in advance for any recommendations.

[jonathanhill]

One of our drama studios that was a complete new build back in 2002 as was fitted mainly with Strand Quartets (PCs, Fresnel's and Zooms) and a few Selecon floods. The room has central heating so never gets very cold or damp and apart from replacing the gels every year and lamps when needed the fixtures don't get touched or bashed around.

 

What wattage lamps are you using in the Strand units?

[Andrew C]

We have LOTS of CCT Miuettes, and these too burn out their holders. I think it is just one of those things that happens with age. Maybe the base gets over hot, pins made out of spec, beyond that, don't know. It is possible to change the holders, but a PITA if they are spot welded to the tray.

[Russ83]

What wattage lamps are you using in the Strand units?

The Zoom Profiles are 650W as they are also used in the main hall (no problems with these so far).

All the others are using 500W Philips lamps.

 

I know from experience the Quartets are a PITA just to clean and from reading the other threads on the BR changing the base or cable is even worse and has the risk of breaking the case.

[Davethsparky]

unfortunately burnt out lampholders are just a fact of life. In most cases it is the heat they are subjected to and the slight weakening/dirtying of the sprung contacts in the lampholder. It happens to all lights, not just theatrical ones.

[ianknight]

It would also be worth checking what lamps are being used in the Lanterns too.

 

They should be T18/T25 but you do find that "Mr Moneysaver" sometimes orders A1/244's instead - the problem being that the T18 has assymetric sized pins suitable for the holder, the A1/244 has same sized pins. The A1/244 fits - it lights up and works but the gap between pin and lamp socket creates a spark that burns out the lampholder and could potentially start a fire.

[Russ83]

Thankyou to everyone for the replies, I'll try get it put in next years budget to test/service the whole rig.

 

Luckily our "Mr Moneysaver" doesn't know much about technical theatre so when I put in the annual £400 lamp/gel order he doesn't know any different. TBH he's more worried about the £30k we spend on toner!!

[Neil Hampson]

We have LOTS of CCT Miuettes, ...

... It is possible to change the holders, but a PITA if they are spot welded to the tray.

The easiest way I have found to fit the new holders is to carefully drill out the brass rivet that holds the lamp-holder together, slide the ceramic part out of the metal leaves that are spot welded to the tray, then do the same to the new lamp holder, taking care that the ceramic does not split open, dislodging the wires and sprung holder. The new piece can then be slotted into the tray, secured by 2 M3x15mm screws and nuts.

[Andrew C]

The easiest way I have found to fit the new holders is to carefully drill out the brass rivet that holds the lamp-holder together

Yep, been there, but had forgotten that dodge.