lumley lampros 300 a/b help req with crossover repair

mickm · May 10, 2008

anyone help me with my speakers , im living in the newcastle area .
speaker is cutting in the protection circuit on my amp when playing music just above very low one channel only

took to my local repair shop [ not a hifi specialist] and he has tracked down to treble unit , driver is ok removed and tested fine but says when connected is dropping to 3 ohms ,looks like a problem with the crossover .

he is not confident of the repair due to not having a circuit diagram and its a busy speaker inside , im happy to pay anyone with the skill to sort , mick

zanash · May 11, 2008

first check your cables for a short ...I had something similar amp would play at low level but with volume up would trip ....a single strand of wire was touching the return once sorted the amp was fine ....

is one side of the heat sink hotter than the other ?

mickm · May 11, 2008

speaker problem

hi, thanks ive tried swapping cables and changed for spares , i was hoping this could have been the problem but cables work fine on the other speaker and in spare bedroom system and are factory terminated

it certainly a problem with the treble unit as when i pulled out the cables running to the hi ternimals [ bi wire ] and just ran the bass units no problem at all [ other speaker perfect ] soon as hi freq connected over heat of the amp then at volume channel cut out , and yes the amp depending on which channel i ran the suspect speaker on did indeed get very hot , as sad as it is , just running the one speaker at the moment swapped to both channels of the amp and no problems at all . thanks mick

zanash · May 12, 2008

could be a failed tweeter .....get borrow steal a multimeter and see what the resistance is ....it definately sounds like a short .....

if your east midlands ish pm me as you can borrow mine

mickm · May 27, 2008

problem was failed musicaps in the tweeter crossover , thanks to vamps music in washington for sorting the problem , mick

Tenson · May 27, 2008

Good to hear it is sorted. I was going to suggest putting the other tweeter in the speaker and see if its okay. If not, then its the xover and mos likely a cap, since there is little to go wrong in inductors. Nice to hear my logic was correct, if a little late

mickm · May 27, 2008

thanks for all the advise the engineer did use to track down the problem , cheers mick