Fluorescent Batten problem

[mlarky]

A pair of 5ft single tube fluorescent lamps in a garage which had been there for about 15 years and worked fine. They are on a single switch. They were not bright enough so replaced with two 5FT 58W HIGH FREQUENCY TWIN FLUORESCENT battens.
Easy to wire to the existing cables.
The problem I have is that they wont start properly. They try to start together. The tubes half come on then both pairs go out. They dont try and restart. Sometimes both will flash, one pair will come on, the other pair will flash and go out. If Im very lucky they will both pairs come on! More often though they both flash and wont come on.
I have checked the wiring, I have checked the switch, I have checked the tubes are seated properly.
Can anyone advise what the problem may be?
Thank you.

 

[davesparks]

It sounds like the normal symptom for either a duff or incorrectly fitted tube

 

[snowhead]

What tubes have you fitted?

 

[i=p/u]

switched start ????

 

[i=p/u]

tubes and starters, then we onto ballast after that the grid needs testing

 

[Guest77]

My god, kill me now.

 

[davesparks]

tubes and starters, then we onto ballast after that the grid needs testing

Starters in an HF fitting????

 

[Lucien Nunes]

Have they accidentally been connected in series? If one fitting is disconnected, does the other work normally? What is the voltage at the fitting input with one fitting lit?

 

[Rundiz]

emergency fittings????