Dansette "Monarch"

[DonaldStott]

Initial safety checks and visual inspections completed - powered up with Lamp Limiter and RCD for about twenty minutes before applying full power.

So far so good - don't you love a loud mains hum ... !

Disconnected one of the wires leading to the cartridge and got a bit of a scratchy noise when I touched it with an insulated screwdriver - so maybe some amp problems as I was expecting a loud buzz?

Photograph of main board attached below - wires, wires everywhere and two that shouldn't be there, but more on that later.

Checked out the Westinghouse FC116 metal rectifier as this is often suspect but I'm reading 234V AC on the input and 251V DC on the output - seems OK?

I'll get around to checking the voltages on the various valve pins later but the Circuit Diagram doesn't list voltages for all pins?

From other Threads and Posts I've noted that it is recommended to replace C4 the audio coupling capacitor notwithstanding C5 and C7 the reservoir and smoothing capacitors. Obviously I need to extract the main board from the record player and to get inside that large can - advice please??

[Edward Huggins]

There should not be that much much of a hum on these so maybe the "large can" capacitor MIGHT be the culprit. This actually has 3 capacitors inside which you will need to buy seperately. It was originally 32uf @275V, 16uf @275V ad 32uf @25V.

[ms660]

Looks like there is at least one variant of the Dansette Monarch circuit. 6.3v Bulb? Extra capacitor?

Lawrence.

['LIVEWIRE?']

I know I've mentioned this before, but when replacing the Cans in Dansette and other similar record players, I usually fit a modern dual 16 or 32uf Can (F&T or similar makes are available from several sources, then fit a small axial 22, 33 or 47uf 25vDC electrolytic to replace the third cap., which is (almost)always the o/p pentode's cathode bypass capacitor.

[DonaldStott]

Originally Posted by ms660

Looks like there is at least one variant of the Dansette Monarch circuit. 6.3v Bulb? Extra capacitor?

Nothing so advanced I'm afraid, just two rogue wires attached to the terminals of one speaker!

Hopefully shown in the pictures below - a blue and a brown wire that don't go anywhere? Clearly this Phantom didn't have access to or know how to use a soldering iron! Of course they'll be coming out a.s.a.p.

Two questions though:-

What's the white powdery substance on the back of both speakers - anything to worry about?

What reading should I get across the speaker terminals??

[ms660]

Is yours fitted with a filament bulb for the power on indicator?

The two loudspeakers connected in parallel but not in circuit with the transformer should measure low ohms, probably 3 ohms or less. Individually they might measure between 2 and 6 ohms, it all depends on what their rated impedance is. A loudspeakers DC resistance is always lower than it's rated impedance unless the voice coil or it's connections are faulty.

Lawrence.

[Edward Huggins]

Well that's just plain old dust and it's on the mains transformer as well. The speakers have a voice coil impedence of 3 ohms and should be wired in parallel. From your photo I can see the old, original, BSR TC8M mono only cartridge - if it still works - just don't play any of your stereo LP's with this.

[DonaldStott]

Originally Posted by ms660

Is yours fitted with a filament bulb for the power on indicator?

Thanks Lawrence - yes it does. Clearly shown in the first picture in my Post #1

Of course the bulb has blown and needs replacing.

[DonaldStott]

Originally Posted by Edward Huggins

From your photo I can see the old, original, BSR TC8M mono only cartridge - if it still works - just don't play any of your stereo LP's with this.

There's a better view of the TCM8 cartridge in my Post #1.

Scratching the stylus produces no sound so I'm assuming it's dead.

It won't be going near any of my vinyl - don't worry!

[ms660]

Originally Posted by DonaldStott

Thanks Lawrence - yes it does. Clearly shown in the first picture in my Post #1

Of course the bulb has blown and needs replacing.

It's not clear in that photo that a filament bulb is used, anyways you've confirmed my original suspicion, how about the larger of the Mullard mustard capacitors, the one that's partly hidden behind the valve in Post#21, is it possible to trace where it's connected in circuit?

Just trying to get a handle on these Dansette variants.

Lawrence.

[DonaldStott]

Originally Posted by ms660

It's not clear in that photo that a filament bulb is used, anyways you've confirmed my original suspicion ...

Sorry, picture of blown bulb below.

Any further circuit tracing will have to wait until I manage to extract the main board.

[DonaldStott]

Originally Posted by ms660

Just trying to get a handle on these Dansette variants.

Noted - I agree that the actual filament bulb itself is not shown on the Circuit Diagram I have for the Dansette "Monarch"?

Is the attached snip not a clue - a 6.3V tap off the mains transformer?

(Of course this was an Instant Download from the Vintage Radio Service Data link.)

[Edward Huggins]

From replacing these myself the 6.3V is correct. You can easily search these bulbs.

[DonaldStott]

I already had a batch of 6.3V bulbs - the bulb was replaced last night.

Just following thorough on Lawrence's earlier Post.

[DonaldStott]

Still struggling to extract the circuit board from this player - managed to unscrew the cheap and nasty plywood strip from the cabinet and slid that out.

Located the metal tags holding the circuit board in place and untwisted three of those but the one at the rear on the left hand side also appears to be used as an earth tag and has had a liberal amount of solder applied at some point!

Referring back to the picture attached to my Post #21 - has anyone else ever been concerned about the proximity of the mains transformer to the main circuit board holding the valve, capacitors and other components, notwithstanding the spaghetti cabling - is there a case for rigging up some sort of shielding here? Obliviously Dansette didn't think so, but ... maybe its just me?

[ms660]

Just wondering why you want to detach the printed circuit board, If the transformer is in the way of servicing operations to the track side just unbolt and move it out of the way then refit when done.

I wouldn't be concerned about fitting any kind of shield, it's not needed if all the AC leads (50Hz) are routed properly.

Lawrence.

[DonaldStott]

Originally Posted by ms660

Just wondering why you want to detach the printed circuit board, If the transformer is in the way of servicing operations to the track side just unbolt and move it out of the way then refit when done.

I thought I was taking the path of least resistance and lowest risk but unbolting the transformer and moving it would probably work better - thanks.

Originally Posted by ms660

I wouldn't be concerned about fitting any kind of shield, it's not needed if all the AC leads (50Hz) are routed properly.

Noted - thanks.

[ms660]

No problem, one thing to note is that quite often those metal securing tags can be untwisted ok to remove a board or whatever but when it comes to refitting and it's decided to twist them back again they can snap off....

Lawrence.

[Herald1360]

In which case, a blob of solder to hold things in position might be better....

[Nickthedentist]

Originally Posted by Edward Huggins

Well that's just plain old dust...

and quite possibly corrosion products from being stored in a damp environment too.

Nothing to worry about really, though it could indicate that there might be other damp-related problems elsewhere in the machine. It may brush off to a certain extent. Some people would recommend not it breathing it in and washing your hands after touching it as some nasty stuff was used for plating (e.g. cadmium).

N.