Homersaurus
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An interesting cause of the fault though, which is very useful to know. Switch cleaner/lubricant use as preventative maintenance might well be worth doing on the (pair of) Penta control board(s).
Would contact switch cleaner sprayed into the switches (when the control board is out of the Penta) be sufficient without resorting to physically dismantling the switches ? I’d be interested to know the level of corrosion in the dismantled switches.
The BM5500 can drive two sets of speakers (actually more) from the two pairs of speaker outlets. Both outlets (pairs) will take the 2 pin DIN plugs to drive two pairs of passive speakers or two pairs of Beolab Penta or both active and passive (pairs of) speakers.
If you connect a 4 pin DIN type plug to speaker 1 outlet Speakerlink you can drive Beolab Penta 1,2,3 and get the display data on the Beolabs. If you connect a passive speaker, e.g. Beovox Penta to speaker 2 then both pairs of speakers will be driven as well. Mute will only work on the main speaker 1 pair.
If you connect a 3 pin DIN type plug to speaker 2 outlet you can connect via an XTra speaker box a remote pair of passive speakers (or even a chain of XTra boxes). The datalink information goes down the 3rd wire so you can connect Beolab Pentas to the XTra box and get data display on the main Beolab Pentas and the remote ones.
For you, I would suggest making up the 4 pin DIN cable (difficult to buy and you will have to source or “manufacture” the four 4 pin DIN plugs). Beolab Pentas will be driven by the amp in the speaker – very little output comes from the BM5500. If passive speakers are connected, they are driven by the BM5500 and will need higher current cable.
Have a good read of “Beolink Master Control Handbook”. Try not to get too excited about the capability of running 2 sets of speaker in different rooms. I have a BM5500 with Beolab Penta 2 out of speaker 1 and an Xtra box driving Beovox Pentas out of speaker 2.
For cables, you can always try Steve at Sounds Heavenly but the 4 pin and 3 pin DIN plugs (made for B&O) are almost impossible to obtain (although I have been lucky on ebay once in a while).
Here is a refurbishment service on eBay:
https://www.ebay.co.uk/itm/295320288254?hash=item44c275fbfe:g:isQAAOSwfzJeQIWC
I have not used it myself, but you can read the feedback for the specific work you require.
I’ve had this with Penta II, 6622, but it’s the same issue for 2s and 3s.
See the archive forum at:
https://archivedforum2.beoworld.co.uk/forums/p/17590/153806.aspx#153806
https://archivedforum2.beoworld.co.uk/forums/p/45751/330229.aspx#330229
As I wrote in the archived post:
“The transistors TR3 and TR4 are on PCB 2, the Control board which, as you say, is the front panel. So 2TR3 and 2TR4 refer to (PCB) 2 TR 3 and (PCB) 2 TR 4. The transistors you have identified on the board are the ones to change. TR3 failing is a common fault and can also be the cause of a Penta always being green and not going into standby (red).”
Good decision. When you get your Beovox Pentas refoamed, I am sure you will appreciate the sound from the system.
If it is just the refoam of the mid-range units, then it is a straightforward job that you could do yourself. I’d rate it as “easy” as there’s no soldering involved just the need to be methodical and to label the wires and connections as you go. There is no need to “shim” the centre cones and methylated spirits will remove the old adhesive when used with a No. 17 knife blade.
It is helpful is you can connect each speaker to a source just to check the tone is OK as it checks the surround and cone are centred.
You can purchase foam surrounds and I would recommend the glue as well from various companies. I have replaced 2 sets in Beovox and Beolab Pentas with surrounds from the Netherlands who produce very good fitting surrounds. Don’t forget to order the backing rings that go between the back of the speaker and the surround into which they fit.
If you require more work, say, crossovers then that does require soldering skills and is more difficult. There is plenty of information on the archived forums.
There is/was a service on eBay offered as well – you buy the service and send your panels of 4 speakers in for refurbishment.
Aside from playing a record, you have the alternative of sending the MMC4 away; some of the companies that refurbish B&O cartridges will also provide an examination report. After a report, you can decide to refurbish or not. Refurbishment can be to standard MMC4 or various upgrades of stylus and/or suspension. Both examination and refurbishment are chargeable, of course, but you need specialist tools to examine the stylus and also the suspension mechanism. Have a scan through these forums for “MMC4”.
That’s what I did – refurbishment of MMC4 to standard. Well worth the cost (and wait).
