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This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022
i'm restoring a pair of beolab penta mk1's i bought and have come across a problem with them that i could use some help with.
when i turn on the speakers i can hear a static sort of noise from all of the drivers on one of the towers but only from the tweeter on the 2nd tower, they both play music fine but with the static noise still slightly audible in the background. i have stripped both speakers down and cleaned them and performed a visual check on the pcb's and components for the usual damage ie heat,cracks,bulging and it all looks to be in perfect condition.
i should say that they are connected to the beomaster 5000 through the speakerlink conections on both ends with 2 pin din plugs.
now onto the beomaster problem
the system comprises of a beomaster 5000, beocord 5000, beogram cd50, beogram 5500 & mcp5000,terminal 5000.
the main problem i have is with the mcp's 2 way coms not always working it seems to be tempremental.
any help/advice would be greatly appreciated.
james.
If you have any other music source, try the Pentas with that to see if the noise is the source or the speakers.
Peter
i tried the speakers with a beomaster 5500 that i just bought and its still the same even when connected via rca plugs connected to the preamp output.
i'm sure its not a source problem as the RL35's i had been using didnt have the same problem, i'll try bypassing the penta's amps to rule them out as the cause which should mean it's the xovers causing it. but it will have to wait till i've finished refoaming the mid range drivers.
finished refoaming the mids and have tried the speakers after bypassing the monoblock amps and there was no static just a nice clean sound coming from both speakers. so it looks like the amps are in need of a service.
from what i have read on the forum Martin aka Dillen is the man to speak to about parts & cap kits for all things B&O, so i'll give him a polite shout and see if he can help me out.
another quick question does anyone know where i could source a set of replacement display covers for the penta's i'm having quite a bit of trouble finding them short of buying another set of penta's.
thanks
james
just a little update, have finished the recap on the beomaster 5000 & the remotes and it's running great & cool.
some pics for those interested
still have to replace the transformer bushes and the cap just to the top right of transformer and the relays.
(any help in where to source them would be great)
fitted a battery socket for easy future replacement.
had to bypass a couple of broken traces.
next onto the BM 5500, just got to order a few more caps then get some time off work to do it.
been absent for a bit but have got a good bit done in that time (pictures will be added soon)
work done so far
on the penta mrk1's
re-foamed the midrange drivers
replaced the plastic display covers twice didn't like the yellow looking ones so picked up some black ones
recovered the frets
also did the re cap on the beomaster 5500 + mcp5500
added a few new toys to the list too, i picked up an ouverture & beosound 9000
now i have done the recap on the penta amps and it was all good until the 2nd amp, while i was adjusting the idle current i knocked the meter probe cable and it shorted on the pcb blew the t2 fuse and kicked the amp into protection mode.
it had shorted one of the output transistors TR31 so i have replaced all 3 of the 2sa1302 with 2sa1943 & all 3 2sc3281 with 2sc5200
i then checked all the other components for damage but only found a few resistors and transistors but they tested fine when removed from the circuit.
now the amp works & sounds fine when the source is connected to through the speakerlink connection, but when the rca line input is used as is needed for the connection from the beosound 9000 with the powerlink to speakerlink cable adapters all i get is a strange & quite worrying noise. (it is a bit like the sound the alien machines from war of the worlds make)
i think the problem lies in between the line input connection and ic1 but the diodes & resistors there read as fine on the multimeter and i replaced c1, i'm now at a loss where to look next.