Halogen downlights not working

Are they all connected to the same transformer or do they have separate transformers at each light? It could actually be a faulty transformer and not the bulb.

When the bulb holders were fitted they could have been wired with a single driver or transformer powering 3 of the light and another powering the other 3. If this is the case, then you just need to find the driver powering the faulty string and replace it. Another option is that the lights are all wired in a continuous string and there is a break in the connection between the first 3 lights and the last 3 lights. This can be confirmed by running a contiuity test using a multi meter.

If you fitted the new bulbs then the transformer is faulty you will need new transformer for the light second thing you should call an qualified person to carry out the installation of new transformer.

Probably need to replace transformers. Sometime it’s best to replace with new one because transformer will cost same or more the whole new fittings.

If the bulbs have been replaced and the 3 lights are still not working, it could be the transformer that needs replacing. However, it could also be there is no continuity between the 3rd light and the 4th light, causing there to be a break in the circuit.