Vintage Bang & Olufsen Penta Restoration “Project Twins” – Part 5

This is the fifth part of the Bang & Olufsen Beolab Penta restoration. For the original post, see:

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

This post will focus of the process of cosmetic restoration. All of the metal was damaged and needed to be replaced. Although B&O still has these parts available, it’s more rewarding to fabricate new parts yourself (and more economical). This is the process to install and refinish the speaker cabinets.

Some scratches and gouges in the plastic parts:

Three step Novus scratch removing polish:

Polished plastic with much improved appearance:

Speaker cabinets internally rebuilt and completely stripped of damaged metal:

Slow process of gluing new metal to the cabinet:

Using my wife’s workout weights to keep pressure on the metal while the glue cured:

New metal (with protective white plastic still applied) glued to the cabinets:

Another shot of the newly applied metal:

Speakers standing up and white protective film still applied to metal:

Another shot of the fresh metal:

All the gray pieces sanded and cleaned, ready for black paint:

First coat of stain black:

Final coat of stain black applied and curing in the garage:

Next: Vintage Bang & Olufsen Penta Restoration “Project Twins” – Final Reveal

  • eGoh Jun 1, 2015, 8:22 am

    Rabih,
    You can buy specialty fabric at electronics stores that specialize in stereo repair. That said, it’s expensive and color options are often limited. I’ve had great luck at fabric stores. The fabric I used was labeled “dance fabric” as I believe it’s used to construct ballet clothes, etc. It was extremely thin and slightly elastic so it made stretching very easy.
    Good luck,
    Eric

  • Rabih Jun 1, 2015, 8:15 am

    Dear Eric,
    great job on you b&o speakers.
    i have just bought 2 penta beovox and i am looking to cosmetically restore them. Since i am a mechanical engineer and cutting and folding metal is no issue at all. however, where can i find new cloth because mine are in a bad shape. do you any adress where i can purchase them.

    Thank you for you reponse. and i will add some pics when i am done with it 😉

  • eGoh Nov 1, 2013, 8:10 am

    Kraig,

    I’ve tried a heat gun on the adhesives that B&O uses, but haven’t had much luck. Of the dozen or so metal pieces I’ve had to remove, only 1 really came off easier with heat. B&O actually has a tool to roll off the larger pieces of metal. I hope your amp is an easy fix.

    Good luck!

    Eric

  • Kraig Oct 28, 2013, 9:54 pm

    Im sorry if you mentioned it elsewhere. I didn’t read all the posts yet.
    A heat gun may loosen glues and make removing the panels easier.
    I’ve used heat guns on cell phones.
    I am going after a faulty amp.
    Ill post what happened when I try.
    Just a thought,

  • Jim Moore Feb 28, 2013, 11:42 am

    Hi again Eric.

    I just realized that you are from Austin. I live in Bulverde, about 30 miles north of San Antonio so we are practically next door neighbors. 🙂
    We have a common esoteric interest. I do B&O tangential Turntable full blown “frame off” restorations. Like you, mine is also a lobor of love. I say that because I sell them and think I make about $2.00 per hour doing so, give or take a buck if I ever broke it down. Looking at your Pentas, I know that you get it.
    Bringing these iconic treasures back to life is a passion and the finished product is it’s own reward. If by chance you are into vinyl, B&O style, I’d be glad to help you out with your B&O deck, any part, any problem, any time. No charge.
    Your Bulverde B&O Buddy. 🙂
    Jim

  • eGoh Feb 8, 2013, 8:07 am

    André,

    I don’t have the measurements anymore, sorry. I carefully pulled a piece off of the speaker and used that for measurements. You’ll need access to professional metal cutting equipment and a metal break: http://en.wikipedia.org/wiki/Brake_(sheet_metal_bending)

    Good luck!

  • André smith Feb 2, 2013, 5:21 pm

    Hey agin 🙂

    I wanna ask you if you know/remember how they cut and bend it properly??
    Like how the measured up

  • eGoh Jan 28, 2013, 9:50 pm

    Monte,

    6603’s are MK I’s. To remove the black bottom cover and get to the crossovers, I believe there are just a bunch of self-tapping screws. The cover does have some foam to seal it, so it might take a bit of wiggling to get it off.

    Good luck!

  • Monte Jan 28, 2013, 9:14 pm

    Eric, great job and nice photos.
    I have a set of B&O 6603 ‘s but don’t know if they are MK I, II, or III’s.
    One question I have is how do you get the top cap off to get at the crossovers?
    I have the power supplies out but can’t get to the crossovers.
    Thanks,
    Monte

  • eGoh Jan 5, 2013, 3:49 pm

    Henry,

    Thanks! Of the 3 amps that I fixed, each had different things wrong. Of the common issues, most of the electrolytic capacitors were shot as well as most of the trimmers. The three had different transistors that were blown. Are you really good at soldering but not at diagnosis? If so, you could replace all the electrolytic caps, all the transistors that attach to the heatsink, and the two trimmers and you’d probably fix 95% of the possible faults. Unfortunately, because of the way the panels mount to the plastic chassis, you can’t take dents out. The panels are destroyed when removing them. Check with your local B&O dealer as I was told they were still available (new, old stock).

    Eric

  • Henry T Jan 5, 2013, 3:26 pm

    Erik

    Wonderful restoration. I have a pair of penta 6603 active speakers and one amp is blown. Was your repair simple enough that you can point out the likely components that need replacing? Also can the dents in the side panels be hammered out? Thanks.

  • eGoh Oct 9, 2012, 4:22 pm

    Paul,

    My woofers were fine and only dust covers needed fixing or replacing. Usually these woofers are pretty durable but it does sound like the cone is misaligned. It’s possible that gravity has caused the problem. Try rotating the driver 180 degrees to see if the problem goes away. If not, you’ll need to source some new rubber surrounds or replace the driver. There tend to be quite a few on eBay from people breaking down speakers for parts. If you do replace the surround, a frequency generator is helpful to test your alignment to make sure nothing is rubbing.

    Hope that helps!

    Eric

  • Paul Oct 9, 2012, 3:32 pm

    Inspiring. I am refurbish a beolab penta mk1 myself. Did you replace the woofers (bass) speakers? Did you replace them with originals? One of mine make a scraping sound. Blown? or must I replace the rubber roll ?

  • eGoh Aug 3, 2012, 4:34 pm

    André,

    I’d check with another B&O since the parts were available the last time I checked in April 2011. They were, however, expensive at around $135 USD per piece.

    I decided to fabricate the metal since just replacing parts wouldn’t be as fun. I worked with a sheet metal fabrication shop to have them cut and bend four new pieces for me. The cost was considerably less, but requires a good shop and a good specification so that they cut and bend it properly.

    Make sure to post some pictures online when you’re done and send me a link!

    Good luck!

    Eric

  • André smith Aug 3, 2012, 4:08 pm

    Hey man,
    Love you work 🙂
    I’m just about to do the same thing 🙂 i have just paint the plast foot and the Amplifier satin black and it look’s beutiful, im soon gonna get help to re-build the crossover with capacitors and all that stuff and also the Amplifier so it’s gonna be like new,
    And i have just order som new clothes ind 100% black

    But i just need on thing….. And that’s new metal and the problem with that is that you Can’t order that eny more ind B&O chop’s, så i wanna ask you how that you cut get new metal? 🙁