I recently picked up a Beomaster 5500 w/ Master Control and Beogram CD5500, 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 system and said he was selling it because the speakers were "no good" with the system. On my drive home from picking up the system, I realized I forgot to ask what kind of speakers he was using. Unfortunately, the seller didn't answer his phone so I headed home.

In a later email, I found out that they were hooked to Pentas that were already loaded into his trunk for the move. He said that the amp in one has 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 system was 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...

Initial pictures:

This project is going to take a bit of time since I really busy working on a new tech startup, but I'll try my best to keep my progress posted.

Now, check out the fried crossovers (both are fried, one more than the other):

egoh:

Now, check out the fried crossovers (both are fried, one more than the other):

These Pentas seem to have seen some parties in their time! The crossovers should be easy to sort out though unless the coils have actually melted and have short circuits.

With some luck, the pentagonal metal cap might still be available as a spare part; worth asking a dealer I think.

I'd leave the pushed in dust caps of the woofers last, they won't affect the sound that much. Good luck, this will be interesting to follow!

***

(Sorry the automod kept your first post ransom for so long, I think it was due to the number of external links to the pics. During holidays, it may take a little while before any of us mods come around to take a look at the queue.)

Wow those Pentas have been abused. Look forward to the restoration!

Welcome to Beoworld.  Always interested in a speaker refurb project.  And another Yank to boot!

But what's with the Bronze level?   Come on, gold, man, gold!

If you continue with pics and descriptions like this, for my part you can stay as a bronze member, to look at, you have problems with at least one coil. Compliments for starting a thread like this and over here.

WELCOME

tournedos:

unless the coils have actually melted and have short circuits.

THIS GUY doesn't do repairs - he just splits them up for parts and sells them. Currently splitting Penta II's and is in the USA.

Hey guys, I sourced a used top cap and top copper trim from eBay. I'm going to look into fabricating all of the stainless panels. Talked to B&O and found out they are still available but quite costly....so, it should be cheaper and more interesting to fabricate.

Coil L6 (1.8mH) for the woofer and L3 (100uH) on the midrange for both speakers are burnt. I'd like to repair them instead of swapping the entire crossover. I can't seem to locate coils with similar gauge wire (32 AWG) so I might just have to wind them. It's been 20 years since I messed with crossovers so I'm a bit rusty. I'm assuming that a lower resistance coil would mess with the design so it's probably better to stick to the factory 32 gauge. Anyone have a source for air coils with 32 gauge wire?

Also, what is everyone's brand preference for crossover caps?

Thanks!

I can't give a higher recommendation to Mark at Meniscus.  He's in the Grand Rapids, Michigan, USA area.  He winds his own inductors.  I would just buy inductors from him, not wire.

I've used all the brands of caps Mark carries.

Thanks Rich, I just sent Mark an email. That would simplify things a little.

I agree it's probably best to use original caliber coils.

For my Beovox Pentas, I used Intertechnik Audyn MKT foil caps. Anything more exotic than that will be diminishing returns for me at least, even regular bipolar electrolytics will be a great improvement over the old tired ones. The basic 160V MKT caps are already physcally so large that it was necessary to snip a bit of the internal plastic structure of the speaker to make the 68µF cans fit.

The 27µF caps will be hard to find, so you might need to use f.e 22 + 4.7 in parallel.

I've heard Solen caps are also excellent, you might find them more easily over there.

Hi Egoh, very interesting projects your doing on Beoworld

Maybe I missed something but what type of Penta's are you working on?

These are MKI Pentas but interestingly, they have MKII crossovers. The original owner didn't service them so they came from B&O that way...perhaps right before the MKII's came out.

Mark is being extremely helpful right now. We're trying to be sure of the gauge. I measure .008" diameter which is about 32 gauge. Based on the 1.1 ohm resistance of the 1.8mH coil, Mark thinks it's about 22 gauge. However, I can't be sure it's not melted and shorting. 

I may have to go pick up a micrometer....I'm measuring with a caliper right now.

egoh:

Mark is being extremely helpful right now.

Very glad to hear that.

Wow! I'm working on a project just like yours.

Keep us posted on your progress!

I picked up a complete used 5500 sysem with CD, TT, TD, BM, MCP, 2 BL1000s and 2 Penta Mk1. My Pentas looked like yours on the outside with both tops bent badly (dragged across floor?).

If you are interested, I made a CAD dwg of the skins that I could forward to you, as a PDF file for your fabricator. Most metal shops balk at the short lips (3mm or ~0.12") at each edge of the skins, leaves no room to create a real sharp corner! I dont know yet which way I'll go with the skins...
I replaced the mid's foam surrounds with rubber and took the amps and housings apart to clean them (amazing how much dust is pulled in by the amp heat convection). If you are not restoring these to factory spec, you could skin them with brushed aluminum foil from alsacorp.com.

My Pentas are now up and running on my BS4500. The refurbished Penta Mk1s sound more rounded from low to high than my BL6000s!
BTW B&O USA has the adapter between PL/SL PN:6275896. These allows you to get the display working on the speakers on PowerLink systems.
Soundsheavenly.com sells complete speakerlink cables 4-pin (M-M both ends) up to 8M long, Item# "spkrlink", for your BS5500.

I did look in to replacing the caps and resistors on the XOs and priced the components at PartsExpress.com with 1% or 5% caps (all caps available), the parts bill is prohibitive at +US$250 for each XO! When they start sounding muzzeled I'll have to bite the bullet.
-------------------------

Beomaster 5500: I have replaced one missing RCA connector on the BM5500 and cleaned the inside of it. Why do people misplace the brackets that are supposed to hold the cover inplace on all these systems? I had to manufacture two of them from scratch with a hacksaw and a bench grinder! The BM5500 sounds really good. Goop cleaner removed most of the grime, however, be careful with the rubbing - you may work through the clearcoat and get down to bare metal!
---------------------------

My Beogram CD 5500 only plays on one channel, needs to go to California for service, unless somebody here knows what ails it!?! I did find soot around two resistors but no burn marks on them?

Next on list is TD (doesent close properly, Belts/Gear track?) and TT (New Belts and new cartridge - soundsmith.com) as well as the MCP (dial wheel not working properly, super glue time?)!

IkeA

Good luck.  And remember:  pics, or it didn't happen!

IkeA, I'd love to CAD drawing! Can you forward it to eric at egoh.com? Thanks! I'd love to see some pictures of your before and after. Do you have a thread.

I just fixed a Beogram CD4500 with a similar problem. I bet it's a blown cap and resistor in the opamp. Check C210, C110, R226, and R126. Other possible suspects are C211, C111. Check all the resistors in this area and you should be able to figure it out. Hope that helps.

Does anyone have the wiring diagram  for the powerlink to speakerlink adapter (PN:6275896). I can guess what goes where, but don't want to fry anything and I have a boatload of DIN connectors.

Thanks for the feedback, I' check the caps and resistors before I send it away.

I decided to buy the skins from B&O since nobody promised they could do the 0.088" inside lips for the skins.
Buying the gear (leaf brake) to do this kind of forming would cost more in shipping than the cost of 4 skins from B&O.

I dont have a thread so I'll send you the pics and the PDF.

IkeA

BTW The fabricators could do a bend but with ~5mm or ~0.2" lip.
This would prevent you from inserting the skinny copper and aluminum colored strips between the two skins and the speaker grilles!

Hi Eric.

A few pictures of my Pentas pre the new skins from B&O.

Wrinkle on back of LH Penta.

Wrinkle on back of RH Penta. Needs a new top cap as well (from B&O).

Re-rubbered Mids. Missing the skin I peeled off and measured.

I started with gluing the ID to the cone. It helps if you stretch (slightly) the inside flange rubber. Experiment... This causes the ID to be "larger" than the “Roll”. Hence the inside flat part tends to follow the cone angle... I discovered this while wrestling with the first surround trying to constantly separate from the cone while it was drying. The rest worked like a charm.

"Chrome dome" on a BM 5500!

This is a picture of my “Shop Amp”. A rescued BM5500 that needs help starting, due to most likely, a defective relay. It starts very quiet and after a second start the sound comes on as it is supposed to. It also squeals when shifting from CD to Tape to TT to Radio???

I tried the alsacorp.com FX Chrome on the BM5500 and it shows every defect under the new skin. I’m glad I didn't skin the Pentas with this. The FX Brushed Aluminum or FX Brushed Stainless would be more forgiving.
Yes the speakers in the background (LH) are a pair of RL60s that I rebuilt the passive radiators and the crossovers on. They really rock now. The other pair in the RH corner are a set of BL6000s that I’m waiting on surrounds for from Holland. These will be my second pair of BL6000s that need to re-rubbered!

I’ll send you picks of the finished Pentas. I ordered Silver speaker cloth for them and I will see how that works out.
If they look like junk with silver, I’ll put the darkest black cloth on them to make them match the BL6000s.

The PDF file is on its way via Email.

Enjoy.
IkeA

Egoh - The adapter that I bought from B&O is affordable!
You get LH and RH adapter in a box for ~US$38.

They use the regular PL cables ~3mm in diameter.
I hid mine under the baseboards and only show the connector.
The RH adapter takes RH signal and connects it to the RCA connector on the speaker.
The data from your Beosystem goes to the oddball 4-pin SL connector (3 pins and a spade)!

The same goes for the LH adapter.

If you need the diagram:
In Danish - http://www.bbdownload.dk/diverse.html  Click om: BeoLink/Master Link

Here is another page: http://www.beoworld.org/beotech/wiring1.htm

I checked my adapters, pins from soldering side:

Left side:

Pin 1 -
Pin 2 - Outside of RCA
Pin 3 - Center Pin on RCA
Pin 4 -
Pin 5 -
Pin 6 - Pin D
Pin 7 - Pin C
Pin 8 -

4 pin RCA from solder side:
    o      A not used
  -----    B not used
  o  o
 C   D

Right side:

Pin 1 -
Pin 2 - Outside of RCA
Pin 3 -
Pin 4 -
Pin 5 - Center Pin on RCA
Pin 6 - Pin D
Pin 7 - Pin C
Pin 8 -

4 pin RCA from solder side:
    o      A not used
  -----    B not used
  o  o
 C   D

------------------------

I hope this helps.

IkeA

It will be interesting to see the penta's with silver frets!  Get a picture on when you have done it! 

Hey guys,

I'll have some updated pictures up this week. But, the midrange drivers have been re-foamed. The crossovers are mostly complete (waiting on a few more caps). Stainless has been fabricated. Waiting on parts for the amps.

I have a simple (and maybe stupid) question. Does anyone know how to remove the plastic from the heat sink of the amp? I'm planning on repainting the plastic and wanted to take it off first (since I didn't want paint on a heat sink). Those pieces seem snapped in there pretty good and I'm not sure how to remove them without damaging the plastic.

Thanks,

Eric