Vintage Bang & Olufsen Penta Restoration “Project Twins” – Part 1

I purchased these B&O Penta MKI speakers off of Craigslist from a gentleman planning on moving out of town. He was trying to lighten his load before his travels. His family was the original owner of the speakers, so it was interesting to hear their history. He said that the amp in one had blown out so he bypassed it and ran the speakers with a Sony receiver. He and his friends named them “The Twins” since they would crank them up and their music could be heard from down the block. I had a feeling this would be quite a project but the seller offered me a good price.

So begins, “Project Twins”

My initial thoughts, before opening the speakers were that I’d have to fabricate new metal, re-foam, replace the fabric, re-cap, and fix the amplifier fault. If only life were so simple…

Here are the initial pictures:

Power mains and fuse box had been cut off:

Damaged speaker frets:

Dry rotted foam speaker surrounds:

Smashed in woofer dust covers:

Missing metal speaker cap:

Scratches and dents on all metal:

Speaker wire sticking out of the bottom:

Another good sized vertical dent:

Dirty and bent top cap:

Resistor unsoldered from excessive heat:

Burnt out resistor on crossover:

Burnt out resistors on crossover, melted coil:

More crispiness:

Another fried resistor and coil:

Missing mains and damaged plastic from speaker wire hack:

Next: Vintage Bang & Olufsen Penta Restoration “Project Twins” – Part 2

Leave a Comment

  • eGoh Feb 14, 2015, 10:18 am

    I’m pretty sure I understand, but can you send me a photo first? My contact info is at the top of the page.

  • Al Sines Feb 14, 2015, 10:13 am

    I had thoughts of cutting the connector going to the amp on my first generation Penta speakers and connecting them to my Sansui amp. Well, it did not work. It had the 4 prong connectors. I then decided to reconnect the cut off connectors. I reattached the like wires and now they don’t work. The Beomaster 5500 works fine and so do the two speakers. How can I get this to working order? AL

  • eGoh Dec 15, 2014, 3:06 pm

    I wish I had the time to help out, but my toddler consumes all my free time right now. The displays aren’t a difficult fix for any decent electronics shop. Due to the condition of the speakers, they may not be salvageable. If the prior owner used the wrong glue, it may prove difficult to repair. Good luck!

  • nick Dec 14, 2014, 9:36 am

    hi there, i have a pair of penta mk 1. the display does not work on one and the mid range speakers have been replaced but badly with glue on cones. would you be interested in fixing them cheers nick

  • eGoh Jul 28, 2014, 9:01 am


    Removing the old foam isn’t difficult, but it’s time consuming and tedious. Just take you time and remove a little of the residue at a time, you don’t want to damage the paper cones. I used a ton of cotton swabs and isopropyl alcohol. Good luck!

  • Lars Jul 28, 2014, 4:40 am

    Dear Egoh

    Nice to find your manual to change midtone foam.

    Is it difficult to clean and to replace the foams

    Thank you

    Best regards