Hello, I have a pair of Philips 532 speakers with Black Tulip 280 pre-amp and my darling 2 year old daughter seems to have blown the mid and high drivers on one speaker by turning it up to 10! Is there any internal protection? If not how can I replace or repair the blown units. Any information (in english!!) would be gratefully appreciated.
Hi Eoghan,
Seems like you've just had bad luck. I won't necessarily blame your daughter for that. Your 532 speakers have separate amlifiers for both low and midd/high. Missing both midd and high sound points towards the midd/high amplifier.
After 30 years the amplifier tends to pull more current.
Once the transistors are heating too much they will blow. Of course a higher volume contributes to extra heating, but one of these days they would probably have burned out anyway.
What you can do to avoid heating is adjusting the dc current of your amplifiers. The box missing midd/high will probably have defect transistors in its midd/high amplifier.
For now I suggest you check your amplifier by measuring its transistors and its 1 ohm resistors. There might also be a blown fuse.
I hope to hear from you again once you've found out more !
Success !
ondertitels 😉
Eoghan,
Philips is not particular well known for over dimensioning. If your transistors appear to become just wires, replace them with a higher voltage type.
I don't know from what country you are, but keep also in mind that in some European countries the mains voltage has increased. So your MFB power supply will also supply - as long as the transfomer can keep up with it - a higher voltage to the power transistors as the suppy to the power transistors is only rectified and buffered with capacitors. It is not regulated.
Good luck
Good point, as I understand Eoghan is from the UK where the mains voltage is 240V.... ❗
regards,
Gijs.
