Martin!
I have been off for nearly two weeks, just so you don't think I lost interest.
Thanks so much for this thread, you must feel so proud of this renovation.
The thought of Stereo, and AFC from valves is astounding.
Make sure that the person who ends up with this set, has a link to this thread, eh!

Andy T.

Another great job! I'd love to know how it sounds with higher-end speakers.

Simon

Hi Martin,

I think we should tell the rest of the world one important think

In Danish there is a word for what Martin has done here:     SÅDAN !

(this means somethink like "You have done am extremly great job - Martin")

/Frede

The Beomeister strikes again!

Great stuff Martin

Chris.

Thanks for all the comments, messages and emails. I cannot tell you how much
your feedback means to me.

A long time has passed, lots of other repairs came through here and I've
had to spend time on other things but the project hasn't ground to a halt.
Not at all.
A strike of luck brought with it a knob of the correct type. It was cleaned and
fitted to complete the set. But that's not all;
A pair of contemporary speakers, the B&O type M, were dug out of my collection and
gently cleaned and polished to look their best. Tested on the bench and found
to be in very good working condition indeed.
They were connected to the Grand Prix and the whole system was placed in the
kitchen to allow for a supervised soak testing while providing entertainment
in these quarters.
What a wonderful system and what a sound. Pure joy !
Valve-stereo for hours.

(Sorry about the bad lighting when the photo was taken).

Martin

Well, that is... after playing for about an hour or so, the set suddenly went
completely silent.
I stood right beside it when it happened and it was quickly unplugged from mains.
After all, it was running on live mains in my house rather than the "protected"
variacs mains on the repairshop bench.
Off with the rear cover, a couple of quick meter readings, a gentle wiggle of the
tubes in their sockets, no obvious faults anywhere.
- Hmm ?

Martin

Good to see the thread continuing

Dillen:

A pair of contemporary speakers, the B&O type M, were dug out of my collection and

gently cleaned and polished to look their best.

Wonder why there never was a 609K with these speakers in a single cabinet?

Dillen:

They were connected to the Grand Prix and the whole system was placed in the
kitchen to allow for a supervised soak testing

NOT in the sink I hope?

I hope the sudden failure isn't too terminal Martin, that would be a real shame for such a beautiful piece

Chris.

No Chris, not in the sink. I haven't given up on it yet and it would clog
the drain, I'm sure. 

Actually, the Grand Prix 609 WAS available with built-in speakers as the "Present"
version rather than "Moderne".
It's pictured at the front page of the service manual, just visible in the photo
with the power supply module, showing it's bad condition fuse holders in
one of the first posts (#19, I think) of this thread.
Just not two-way speakers like the Type M, but with two full-tone drivers
in each side, one pair facing forward and the other pair facing out the
left and right sides respectively. A quite impressive piece with an equally
impressive sound.
It was also available as a TV/Radiogram with built-in speakers, also as
one single cabinet, the Grand Prix TV 609RG and I believe the two-way speakers
here are fairly similar to the M's:

Martin

Anyway, it had to go back on the bench.
Mains on and it started playing. It played for two hours, showing
no problems. Must have been an intermittent contact in a valve socket then - so back
in the kitchen it went.
After about an hour or so - right in the middle of a Beatles programme on FM, very
appropriate for listening to this set BTW, suddenly complete silence again.
- ?
Instead of unplugging it right away, I just kept one finger on the wall outlet switch,
ready to flip in case of disaster and I started pressing knobs in an attempt to
diagnose the poor thing.
The slightest touch of any of the pushbuttons brought the sound back nicely but
as soon as I removed my finger, silence ruled again.
So we obviously have a switch bank fault.
Well, the set stood many years unused, showing light water stains etc. so I wouldn't
be too surprised if slight oxidation prevented good contact somewhere and a thermo fault
can never be ruled out.
Besides, the switch bank wasn't taken apart when serviced but merely cleaned using
a contact cleaner agent to which all contacts seemed to respond nicely.
I generally don't like using contact cleaner unless able to clean off the mess afterwards
but taking apart the whole switch bank, let alone dismounting it from the set, sounded
like a lot of hours work and not something I would enjoy doing unless absolutely
necessary, so I decided to try the contact cleaner again.
I did so and brought the set up on mains again.
This time it passed one hour and played along nicely.

Martin

- For two hours...
Then silence again...
Still sensitive to touching the switch bank.
- ?
I tend to get quite hooked on solving strange faults, especially stubborn ones
like this, so back on the bench it went.
Every switch contact was tested for continuity with the meter.
Each and every one of them found to be functioning correctly. Also when warm.
- What is going on here ?

That was when my eyes fell on the bottom cover that was put aside while the set was
on the bench.
Full of holes and with its upper side covered with aluminum foil, it provides
shielding under the high-impedance and high-frequency circuits while allowing for
ventilation to the warm components inside the set.
The aluminum foil had losened and lifted in some areas. A couple of places it even had
little imperfections in the form of raised tears and bends.
Hmm... what if this cover bends upwards ever so slightly and/or the main PCB board bends
downwards the same way when warming up, could one or more of these fairly small
imperfections actually reach up and touch a solder joint or a component on the underside
of the main board ?
Certainly !
And it's aluminum, conductive and electrically connected to the chassis when mounted
so would have a lot of potential for causing a fault like this - or even worse.
The tears were smoothed out and the foil was glued down where it had losened from
the 3mm masonite base of the bottom cover.
While working with the glue, the set was testet without the cover to confirm the diagnose.
Confirmed !
It played fine for hours on the bench so the cover was mounted again and the set
transported to the kitchen once more.

Martin

You didn't catch that little mouse who was sharpening his gold-plated teeth on the octal tube sockets, did you?

They are the ones who always cause these intermittent problems

Martin, you've done a beautiful job!

I also want one of those - but in the meantime, I have to be satisfied with my restored Grundig 4016 - also Stereo! This one took me about a year to do completely.

Menahem

Thanks.
Yes, Grundig made wonderful valve sets. Some are quite advanced indeed, I especially
like the equalizer function on this one. Quite extraordinary for a valve set.
They also made "remote controlled" valved sets - cable control that is - but still
putting a distance between them and most other radio producers.

-

The Grand Prix was brought up on mains again and this time it played for eight
hours nonstop until switched off for the night.
The whole next evening too.
No further problems were noted.

Martin

Today, just for fun, I did a little setup.
Unfortunately, it ended up showing the limits of the microphones and kitchen
acoustics rather than the capabilities of the Grand Prix but still I managed to
catch a little bit of stereo that I would like to share with you.

http://users.cybercity.dk/~dsl42943/Lyd01.mp3

Martin

Nice Martin :)

Sounds very good. I was listening today to my Jet Present 607 which was the subject of one of these threads, and I'm sure you'll be glad to hear that it is still working 100% and giving that unique valve sound to my collection!

Are you keeping this one for your own collection?

Thanks John,

Great to hear that the JET is still doing fine. I still remember the day I
proudly brought it home and it was, and still is, a very nice radio indeed.
Always nice to know that my little "babies" are taken good care of. 

I have very limited room for my collection so this Grand Prix and the speakers
will have to go but not until I'm done playing with it.
Besides, even though it may look that way, this thread is not near its end just yet...

Martin

...will look forward to reading the rest Martin :)

Hi Martin,

The stereo sounds nice, but I'll bet that it sounds much better right there!

I know that one cannot capture the "tube sound" on mp3.

That's why we're all here spending our time on all this beautiful vintage stuff!!!!! 

Menahem

Beoworld is for "Everything Bang & Olufsen" and Beoworld really
does cover a wide range of B&O's product suite but still there are
things that rarely - if ever - gets any mentioning here. Mainly
the vintage things, it seems, so I would like to grab this
opportunity and test the waters for interest;

Having the Grand Prix 609 and speakers running fine now, I was
very curious about the echo-thing and wanted to see what all
the fuzz was about back then some 45 years ago.

B&O produced a couple of echo-units around that time.
The Grand Prix 609 service manual mentions the EK4;

Martin

Gosh Martin! 

You have so much stuff!

Andrew

Hi:

Do those radiograms with TVs inbuilt ever come up for sale? Don't know why but  I would like one!

Thanks

Graham

The floorstanding vintage B&O units are generally rare to find.
I suppose they take up enough space to be annoying to hold on to for years,
especially if in need of service too (and most are) so many owners gave up
and threw them away.
The 1960's Grand Prix and Master Deluxe TV/radiograms, being some of the later
models, do come up occasionally, about one or two every year seems to be
the frequency but their condition varies greatly, their selling prices likewise.

Martin

The B&O echo units are also considered rare and this particular
piece, sadly, hasn't got much going for it in the looks department.
I'm not talking about its design - which in itself is a fairly long
way from what we are used to see on these webpages and surely quite
a distance from anything Jacob Jensen - but it's mere condition.
It's once grey hammer-finish lacquer is showing a vast amount
of surface corrosion, dust and dirt.
It's functionality is unknown and there is something, a small
object, rattling around inside and a somewhat larger and more
"substantial" structure banging the casing from the inside
when the unit is tipped.
The smaller object may just be a little screw.
The larger object ? Well, we'll have to see.
All this will have to be looked into, the most important
thing is that the previous owner didn't just throw it away.

Martin

Oops! Think Lee and I chucked one of these not so long ago! Rather better condition than that as well!

Hello Martin,

These echo things normally contain a mechanical unit called "echo spiral" (?), in German "Hallspirale".

On one end of the "spring" there's a coil producing vibration and on the other end there's another coil receiving them.

If you knock on those springs they produce a nice "twanging" sound.

I always prefered the tape-type echo machines as the spiral things had terrible frequency responses, even worse than the tape ones.

Gunther