MID Not Working

I found one of the bulbs on my MID was not working so decide to replace them all. Brand-new bulbs in and guess what? - None of them illuminate!! AARRGGH!

I have checked and re-checked the bulbs and they are fine (continuity check across the contacts). The only thing showing when I turn on the ignition is the clock/date section. Nothing else is showing - any suggestions or has it decided to die.

Also, can the car be driven OK without the MID connected?

Just to add: I have replaced the fuse to the instrument displays. You can see the MID pixels (just) and they are all showing OK - it is just the background illumination that won't work and I don't know how to strip this unit down to check internal connections.

I've checked the bulbs - definitely 12V, 1.2W. It seems that there is no 12V power to the two metal rails that the bulb contact bridge when they are twisted into position.

I have checked the pins and these are all present. The bulb behind the clock/date section is illuminated when I turn on the ignition. I can see the pixels (just about) and they are all present. INformation changing as I press the different buttons.

When I press any of the information buttons(e.g. range), the back-light bulbs do not illuminate. I have swapped the bulb from behind the clock/date with one of the other bulbs and the information back-light bulbs still do not illuminate when a button is pressed. I have therefore ruled out the bulbs as being at fault. It appears that the trigger from pressing one of the information buttons is not causing the back-light bulbs to illuminate - any ideas anyone? Is it something inside the MID or is there an external control/relay/switch/fuse that reacts when an information button is pressed to give power to the illumination bulbs?

I understand/remember that the status of the unit when the ignition is switched off is unlit (apart from clock), and only lights up when a button is pressed?

Unfortunately that didn't work. The reason I took the MID out was to replace one bulb (nearest to glove box) that had blown. All the others were working OK.
Like a fool - "if it ain't broke, don't fix it!" - I decided to replace all the bulbs. Now only the Clock/Date location will light up a bulb.
If I put a confirmed (tested) working bulb in any of the other display slots they won't light up. I don't understand this, as looking inside (as best I can) it appears the metal strips that supply the power to the bulbs appear to be powering the bulbs in parallel, not in series. Therefore if one bulb was blown, the others would still be lit (as was the original problem).

However, if I recall correctly, the MID display section doesn't light up until one of the info buttons is pressed - therefore there is something (switch/relay) that determines when power goes to these bulbs. I have contacted the "pixel Repair" guys on Ebay, but they only do just that - replace the pixel strip and any blown bulbs.

Does anyone have any suggestions?

UPDATE:
I purchased four new bulbs form BMW £4.80 Each!! - Again, the bulb behind the clock illuminates but the other three do not. The voltage across the metal strips supplying these bulbs is a constant 9.6Volts, when the ignition is switched on. The voltage doesn't change when any of the information buttons are pressed. I've checked the connector plug and the wiring into it, all seems fine.
Does this give a pointer to what the problem could be?

Is there an electronics engineer amongst us? I am still trying to find the problem with my MID. IF it is a simple component failure, then maybe I can save myself some money. The attached picture shows the MID without the rear cover. I have determined the layout of the earth and 12V live feeds to the bulbs. The metal rails that the bulbs secure against are soldered into the PC board, marked on the picture. There appears to be a transistor "gating" the live feed to the bulbs behind the MID display. I presume this is "switched" when you press any information buttons. If I shunt a live feed to this rail - all the bulbs illuminate, so the bulbs are fine. Can anyone assist?

Incidentally, only the pins on the Left of the input socket are used. The PCB shows connection points for an input socket on the other end of the board. I have wondered if the MID from the 3 Series (looks the same form the front) would fit. Although it has two input sockets on the rear, I wondered if It would work with only the socket on the RHS used (RHS looking forwards to front of car).

8er.org/forum/index.php?attachment/22655/

Timm,
That's really helpful and supportive. I am no electronics expert - I would be happy to post it to you. Please PM me your address. Cheers!

Just like to publicly thank Timm for sorting out my MID - He determined that the problem was as suspected in my photo-post - the transistor had blown. This is what this website community is all about - a God's send for those keeping these cars alive and running. Thank you!