With the new potentiometer mounted, there's only a few more things to check before
applying power to the set;

One thing is resistors. It could easily be a chapter of its own but I won't
go into much detail here about how and why, but merely conclude that in
some positions the old coal resistors tend to go high in ohmic value.
Particularly if high value resistors work in high voltage circuits such as
anode resistors in a valve set. It's very common to see this but the Beolit 39
hasn't got any anode resistors.
Of the three valves (not counting the mains rectifier), 2 have tuned
circuits at their anodes, acting as anode loads and the output valve has
the output transformer.
However, there are a couple of high-value resistors, 1 Mohm or higher,
elsewhere that will need checking.
A few measured high, about +50% or more so were replaced.

An ohmic measurement across the mains input to confirm that everything looked,
if not fine, then at least safe to power up.
Actually, the only thing we can measure this way in a set like this is the
heater chain.
Everything looked fine - well almost...
The switch in the new potentiometer works the wrong way. It's on when pushed in.
In my entire life with radios I never saw this before.
Happy to have found a source, I bought a couple of these potentiometers so I
will try to open one and see if it can be changed.
Well, I suppose that's just one more thing on the to-do list and I will use
it as-is until something comes up.

Check everything again.
The schematics was scrutinized and compared to the set.
One single capacitor was missing. A suitable component was fitted to where
it was obviously cut out and everything now seemed within reason.

Time for the first power up;

Speaker plug mounted to the chassis ...
Mains connected to one of the RT12 variacs ...
1m lead optimistically connected to the antenna input ...
AC voltmeter across one of the valve heaters ...
Clear the workbench ...
Power up the variac ...
Slowly bring up the mains voltage while keeping one eye on the voltmeter
and the other on the supplied mains current meter on the variac ...

Ohhhhhhh nooooooooooooooo.

Dillen is missing in action.[:'(]

Thanks for your concern guys, I cannot tell you how much I appreciate it ! 

Current meter reads 200mA = spot on.
AC voltmeter across the output valve heater reads 42 Volts = a bit lower
than the 44V given in the service manual but definitely acceptable and
with a margin to the correct side with regards to eventual overrunning of
the heaters.

Power off again. Feel everything, valves are warm, dropper resistor likewise,
no other hot components and no bad smells.
Fine so far.

So we have all the valve heaters working now. Time to move on to the
secondary side of the rectifier valve.
A DC Voltmeter got connected to the high voltage section of the smoothing
capacitor. This will give me an idea of the condition of the rectifier valve and
at the same time be a good indicator of eventual electronic faults since any
bad leaks or shorts will load the rectifier and keep down the high voltage.

Power up again.
Wait 30-40 seconds for the valves to warm up, keeping an eye on the magic
voltmeter digits, keeping one finger at the variac OFF button ready to
cut the supply in case something goes wrong.
Slowly but certainly the voltage rised from zero to apprx 210 Volts.
This is good news in that it tells us that the rectifier valve is working fine
and, held up against the service manuals 205 volts, it tells us that there are
no serious electronic faults in the set.
Still no smoke and as the high voltage rised, the speaker started to
emit a faint humming.
Indeed a pleasant sound to a radio restorer and the first self-made sound
from this set for years.
However, no programme sound can be heard anywhere on the dial.
Switching wavebands produces a mumbled crackling and touching the output
valve's top grid cap with an isolated screwdriver produced
a very faint buzz from the speaker so the output stage is definitely doing
something but obviously we are not quite home yet.

Martin

Sounds great!

Tune in next time here on Beoworld classics when Dillen is going to perfom another magical stunt.

The old Beolit 39 story will contiue.

With the high voltage about right but only faint sounds, it was decided time
to replace the output stage valve.
A wonderful NOS (New Old Stock) Philips Miniwatt CBL 1 valve was unpacked and fitted.

Martin

Nice to see things are going well with this Martin.

Craig

Oh oh! Martin.
Impatient to know the continuation of the story...

Marc

Marc wrote "...Impatient to know the continuation of the story..."  So am I  

Power up again - wait for the valves to warm up.
Changing wavebands now produces a clear crackling and touching the CBL 1 grid cap
rewarded me with a somewhat louder buzz.

Time to clean the wavechange switch though we will probably never be able to
remove all switching noise. A thud or crackle as the switch is operated should be
considered normal for most valve sets.

Faint static is now present. I would never expect it to receive anything
clear and bright with only the 1m lead as antenna so static is fine.
Still, travelling the dial about the center of the medium wave band, suddenly something
could be heard.
Putting one ear close to the speaker allowed me to listen to the first programme sound
from this little beauty for decades.
Very faint and pulsating in volume but there it was. Definitely violin music.

Martin

Dillen:

Marc wrote "...Impatient to know the continuation of the story..."  So am I  

Power up again - wait for the valves to warm up.
Changing wavebands now produces a clear crackling and touching the CBL 1 grid cap
rewarded me with a somewhat louder buzz.

Time to clean the wavechange switch though we will probably never be able to
remove all switching noise. A thud or crackle as the switch is operated should be
considered normal for most valve sets.

Faint static is now present. I would never expect it to receive anything
clear and bright with only the 1m lead as antenna so static is fine.
Still, travelling the dial about the center of the medium wave band, suddenly something
could be heard.
Putting one ear close to the speaker allowed me to listen to the first programme sound
from this little beauty for decades.
Very faint and pulsating in volume but there it was. Definitely violin music.

Martin

Fantastic Martin. how long should the lead be for the antenna be then?

Craig

This is miraculous! the resurrection of the Beolit is gently coming up!
Perhaps could you listen to Gold, my favorite Radio in UK on 1548 Khz?

Marc

With a radio like this, it matters a lot what you play.
Britney Spears and Michael Jackson won't sound right.
Andrews Sisters, Glenn Miller and Benny Goodmans 1938 Carnegie
Hall live Concert would !

Hopefully, I will be able to listen to Gold on 1548 KHz sometime, I'm sure
that would be the thing to play sunday mornings while the coffee is brewed.
The chance of that is better than that of Radio Luxemburg, I suppose
but I still have a long way to go before that dream can come true.

Generally, for AM reception, it goes that the longer the antenna is the better.
I've had good results with a piece of wire on the ceiling, running the length
of my house which is apprx 12-13 meters.
That said, the ideal AM antenna should be able to rotate since AM usually is
far more directional than FM but obviously that would not be practical with
leads of that length.
A ferrite antenna would be the way to go to keep it practical and later on B&O
put them inside the radios and also made them rotary.

I have a B&O AA10 Active AM antenna that I can connect, it delivers crisp
and strong signals but I would like to hold that part until the set is ready.
I still have to find out why the volume is so low.

Another thing is that after being powered up for about 2-3 minutes, a vast
amount of crackling started to occur.
This is a typical symptom of bad valve pins/socket connections - contacts moving
ever so slightly as the valve warms up, expanding its base and eventually
the socket.
The output valve in this case is brand new and wasn't cleaned together with
the other valves so I'm sure that's where this problem lies.

Martin

I would attach at least 4m of aerial wire and a signal earth.

have you missed any of the wax/electrolytic caps? sometimes they are in the IF cans

Try moving the valves in their sockets, could be dirt .

Check coils/wavechange switch for continuity -your violins could have been from Shortwave picked up by the oscillator coil 

nearly there good luck 

For those of you who expressed a desire to own one of these earler in this thread, I came across this one on a swedish site: http://www.blocket.se/vi/17911967.htm?ca=7_s&last=1

I believe 12000 SEk would be in the order of 1300 EUR. The advert and the picture tells a story of a mint, fully working example.  If this is true, would the asking price be fair or what would be a fair price?

Sverre

I think this particular advertisment was handled already, or was it in another thread? Anyway, that brown radio is not Beolit 39, it's Jet 505K, built after the war. Not quite as rare.

Edit: found it. Apparently the seller hasn't read his emails...

Thank you for letting me know, I should have known that the community would have discovered this long ago....

Maybe the seller does not want to read the particular email he was sent

Sverre

Long time passed and not a lot was done to this project for different reasons.
I've had two consecutive water damages in my repairshop that forced me
to evacuate the rooms. First one was "just" 4-5000 liters, second time is not
clear but it was considerably more since noone was at home when it happened.
Moving out is quite a task but luckily I keep everything on shelves so
no B&O things, instruments etc got damaged.
Still, it will be at least until the end of the year before the workers
have finished repairing ceilings and floors and before I can move back in
I'm left quite disabled.
Anyway, I have now set up an emergency repairshop at home with just a
small amount of tools and instrumentation to just do the most common things.

It's not all bad though, as it does leave time for other things, such as locating
a proper volume control potentiometer with a push/pull switch that is on when
pulled out and off when pushed in and this was exactly what I managed to find.
It had the same problem with the too short shaft so I had to repeat the job
of shaft extending. Another cheap modern potentiometer donated its plastic shaft
and with two-component epoxy and a piece of plastic tubing the result is
once again very good.

Martin

Valves are generally long-lived but unlike transistors and diodes, that usually
either work or not, valves get worn with use and gradually loses emission.

With this in mind, I would like to replace the frontend valve, in this case a CCH2.
The CCH2 is actually a quite rare valve and finding one would normally be a bit hard
but I was proved wrong; I put up a local ad and only a couple of weeks later I
had a nice looking CCH2 valve in my hands.
It was fitted and it provided for a huge change in that the dial now is filled
with stations, mainly on medium wave but there are a few on long wave and ...
*sigh* ... silence on short wave.
Anyway, it does give me something to work with - as if I hadn't enough already -
and the general motivation rises.

As the sound was still fairly low in volume, a longer antenna was tried.
15 feet of lead was put up across the ceiling. It gave better results in the
form of more stations - still none on short wave - but the volume remained the same.
Since the output valve is brand new out of the box, no doubt I will have to
look into the IF amplifier and eventual AGC control to get this right.
The IF amplifier valve in this set is an EF9. The service manual and the lettering
on the chassis asks for an EF5.
EF5 and EF9 are quite identical in most aspects and in most cases an EF9 would be
a fine substitute but the EF9 has a few more "adjustables" that noone thought of
when the Beolit 39 was constructed.
A brand new, shining red, Tungsram EF5 was fitted which brought a bit more
volume. The radio can now play at a pleasant livingroom level but only with the
volume control at its highest setting.
It plays fine and with great continuity, no crackles after the output valve
had it's pins cleaned and the tonecontrol seems to work too, adjustable from
clear to mumbling.

Best thing is that it seems the dial is still nicely calibrated with tuning
in to the stations and countries marked on the dial having their mother
languages reproduced accordingly.

Photos will be attached later...

Martin

Hi Dillen

can you check the output transformer? -does the circuit data sheet give ohmic values. sometimes the primaries burn out through layers but are still intact. does it get warm? 

Is there an old capacitor 'leaking' your AF power away? 

Do the IF transformers iron dust cores look like they have been moved?

 if you don't have shortwave check the wavechange switch and coils/trimmers 

Thanks for your comments and suggestions.

I am very tempted to buy the output transformer theory.
The transformer works in that it passed signal from my
signal generator to the speaker but if the impedance is
correct, that's a different story.
One of the things I didn't check when I had my own
Beolit 39 down for comparison.

Anyway, to explain briefly what can happen;
The output valves grid coupling capacitor isolates DC
from the output valves grid, allowing only AC (programme sound)
through.
Any DC here from a leaking capacitor will keep the output valve
constantly driving current.
Even if the output valve will handle this for a short time
without being damaged (unlike a transistor-based amplifier that
would be destroyed almost instantly), the output valve will eventually
be damaged and lose emission.

What further supports the theory is that the output valve grid coupling
capacitor is this little fellow:

Martin

It may not be obvious to everyone, but this type of mustard colored
capacitor was heavily used in the late 50's and up through the 60s.
It was definitely not around in 1938 so it must be the result of
a previous repair.
No surprise since the original capacitor in this position would have
been a wax-paper type and it would have started to leak many years ago.

So we have the following scenario of this Beolit 39 coming in for repairs.
The "repair guy" finds the bad capacitor and replaces it.
It cures the fault but leaves the set very quiet because of the
output transformer that got toasted by the high DC current delivered
by the output valve.
Unable to diagnose this fault, he removes the volume potentiometer
and bridge it (and the power switch) to get maximum volume (which was
not much with the mounted valves).

During my repair process, I found the output valve no good and replaced it.
I checked the coupling capacitor and was quite happy with the mustard
colored type which is an extremely reliable type.
But . I didn't check the impedance of the transformer, only that it was
passing signal in some form.

I will check the transformer as the next thing, I may even want to compare it to my own.

It's not running hot, even after 2 hours of playing and the service sheet does mention some ohmic values...

Martin

Sorry to hear about your water leaks Martin. Great to see you are working on this project again though.

Craig