I just replaced a bulb on a defective HF3480 that I bought from ebay for 5 euros.
Removing the bulb was pretty hard. In short: Remove the rubber feet, uncrew the bottom screws, use a small screwdriver to lever up the top cover, unscrew the metal warning sign (which also holds it together at the top), pull on the plastic housing until you start unclicking the plastic hooks on both sides. The plastic is surprisingly durable, but proceed with care. Once the covers are off, you are looking straight at the bulb.
Do not pull on the actual bulb. You will break it and have a much harder time going further (I tried, believe me). Unscrew the white bottom plastic cover around the bulb (at the bottom there is the power supply - do not touch anything). You do not need to lift the black cage. Instead unscrew the two white outer casing parts around the bulb. The glue covering the base is quite soft, you can remove some of it with a small screwdriver to make the process easier. Remove the two white brackets by separating the interlocking "arms", after that you can pull them off. Now grab the base of the bulb, push the two black hooks back and pull gently. The bulb's "feet" will hold onto the connector plate very strongly. I pushed a screwdriver in between and started wiggling next to one foot at a time. I finally got it off after a few attempts.
I then bought a random OSRAM G24q-3 26W bulb from the local hardware shop. This is a slightly different looking type of bulb. It did not fit quite exactly, as the base of the new bulb is half a millimeter too tall. The hooks on the black plastic base do not reach. You could use a file to remove a tiny bit of the hooks, but you have very limited space to work in there. It is possible to just leave it like this, screw down the two white brackets (which also hold down the base) if you can live with it not looking straight, you will likely never see it again... and the brackets' grip of the bulb is even much stronger now due to the hooks being squeezed in between.
Whatever you do, make sure to attach the bulb FIRMLY. I tried with the bulb just pushed into the sockets and while it SEEMS fine, the bulb randomly stopped working after a short time and required a power cycle of the lamp to work again. I believe the (quite significant) heat output of the bulb may cause thermal expansion somewhere so that the feet can ever so slightly loose contact. Screwing it down using the white brackets worked. I also bent the "metal arms" of the connector plate a little towards the hole, no clue if that was what did it.
The new bulb seems to work perfectly. I have had it burn in on max brightness an hour without a problem.
The entire process is not for the faint of heart, but does not require a lot of technical understanding. While I enjoy tinkering, I did not enjoy this one. An example in planned obsolescence and anti-repair design.