Dansette "Monarch"

[Edward Huggins]

There should be absolutely no need to remove the printed circuit board from the chassis. You are just making yourself extra work and risking track damage.The whole unit unscrews from the wooden base inside as one piece. When working normally as designed and properly earthed, there will be little or no hum at all from the amlifier.
With the volume at 3/4 full you would need to put your ear close to the speakers in order to hear anything.

[DonaldStott]

There should be absolutely no need to remove the printed circuit board from the chassis. You are just making yourself extra work and risking track damage.The whole unit unscrews from the wooden base inside as one piece.

As Lawrence suggested "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 don't see any other way of getting proper access for servicing operations - hope we're not talking at cross-purposes??

[DonaldStott]

Mains transformer unbolted and moved to one side which now means that the circuit board and Output Transformer have been liberated from the record player cabinet - makes things so much easier. Lots of photos taken and sketches made to ensure everything goes back the way it should.

Now what did we find - well the big surprise was two components not shown on the circuit diagram I downloaded for the Dansette "Monarch"!

Firstly we have a 1MΩ resistor, let's call that RX, which is reading 1.042MΩ in circuit and is connected at one end to a shared earth with R11 while the other end is connected to Pin 1 of the ECL82 valve - the Control Grid ? (This resistor only appears to have three bands - brown, black and green).

For the sake of completeness the other end of R11 is connected to Pin 2 of the ECL82 valve (k, g3, s).

Secondly we have a 0.047μF capacitor, let's call that CX, which is also connected at one end to Pin 1 of the ECL82 while the other end is connected to the conducting core of the co-axial cable running from the Volume Control.

These additional components are shown in the photographs below.

Don't think I need to replace these or any other resistors as they are all reading within tolerance (in circuit) while C4 (0.01μF) looks ok as well?

That just leaves the electrolytic C3 (64μF) and the electrolytics in the large can C5, C6 and C7. I've attached another picture showing the underside of the board with the can connections - any advice will be welcomed on replacing these??

[Edward Huggins]

The Dansette "Monarch" was made from c.late 1963/early 1964 onwards and this followed on from the "Conquest Auto". Essentially it followed the same circuit design as the Mark 2 version of the "Conquest Auto" (ECL82 amp.) but with edge mounted controls and a seperate on/off swtich, but there might also have been some slight circuit variances introduced in this time period.

[DonaldStott]

Looking for a quick reply - is this the correct version: -

https://www.amazon.co.uk/X5M-CARTRID.../dp/B01D39FV9Y

https://www.gettheneedle.co.uk/bsr-x...lp-stylus.html

Or what would be a suitable ceramic replacement??

[Edward Huggins]

Yes, the BSR X5M is the ideal cartridge for your Dansette. It's Stereo-Compatible Mono. A Ceramic might give less output.

[DonaldStott]

Thanks Edward, BSR X5M ordered.

[DonaldStott]

Can someone enlighten me on the four connections for the multi-capacitor can - see picture below.

The one on the right hand side is the common earth and I think the one at the top is for the 25μF 25V C6.

Just want to make sure before I attempt to fit the 32μF+32μF dual-capacitor from Cricklewood that has three tabs - C5 and C7

[Station X]

Just trace which tag is connected to pin 2 (cathode) of the UCL82. That will be the 25uF section which is the cathode bypass capacitor.

When looking at the print side of the PCB valve pins number clockwise from the gap.

[ms660]

The one that connects to the rectifier is the HT reservoir capacitor (32uF) The one that connects to pin 7 of the valve is the HT filter capacitor (32uF) aka smoother. The one that connects to pin 2 of the valve is the cathode bypass capacitor (25uF) The one that connects to chassis is the common -ve of the above capacitors.

EDIT: Post crossed.

Lawrence.

[Station X]

If the OP is in doubt, perhaps he could post a picture showing more of the PCB ie include the UCL82 base.

[DonaldStott]

Thanks Lawrence and Graham - I'm pleased that I identified the cathode bypass capacitor (25μF) connection!

Hopefully the tags on the 32μF+32μF dual-capacitor from Cricklewood are orientated accordingly.

[DonaldStott]

While waiting for some electronic components to arrive I thought I'd make a start on the mechanicals.

Some questions.

The first picture below is the idler wheel assembly and as you can see the rubber wheel itself gets bunched up when the speed selector is operated. The outside of the wheel and the stepped pulley have been cleaned with IPA so they are not sticking.

The second picture shows the cam and trip pawl assembly where there is evidence of old grease - from my searches through the Forum I understand that there should be no grease at this location?

The third picture is from underneath and shows a white wire that seems to have been cut cleanly - where is this from?

Any help would be appreciated - thanks.

['LIVEWIRE?']

Check the 'sticky' threads about servicing autochangers for information on how to adjust the jockey pulley - a.k.a. idler wheel, the rim of which should be in contact with the central part of each 'step' on the motor pullet. The Trip Pawl (two levers in the bottom L.H. of the cam gear in photo #2) should be free of any lubrication. The white wire is a 90v 'tap' on the motor winding designed to supply the heaters in a typical one-valve record player - not needed in this case. Provided it is insulated from everything else, nothing needs to be done with regard to it. I often slip a short length of heat-shrink sleeve over the end of unused wires, and fasten them clear of any metalwork or other wiring.

[kirstyd]

The idler wheel is only like that because the turntable isn't in place and when the machine is in the off position it should not be in contact with anything

['LIVEWIRE?']

Good point, kirstyd. I forgot to mention that. IIRC, the dismantling instructions for most rim drive turntables specify that the speed should be set to 45, and the deck control to the 'off' position when removing & refitting the platter.

[DonaldStott]

Thanks kirstyd and LIVEWIRE - that explains a lot. All is now well with the Idler Wheel assembly.

I've trawled through all the Stickies but can't find the "dismantling instructions" of which you speak?

I'll also use a bit of heat-shrink on the end of that bare white wire to ensure no possibility of shorting with any metalwork etc.

['LIVEWIRE?']

Sorry if I misled you, Donald. The dismantling instructions of which I spoke are part of BSR's original documents, either on the printed cardboard disc which came with most of their decks, or in their original service data. The reason for setting the deck as described is to prevent the idler wheel being trapped by the rim of the platter when removing/refitting the latter, and to prevent flat spots forming on the idler if it is left in a playing position with the power switched off.

[DonaldStott]

Thanks again LIVEWIRE - you can guess my next question as a quick Google search came up with nothing.

Anyone got BSR's original documents or service data or should I Post in the Wanted section??

[buggies]

Tried to attach a scan of my copy but pdf just too big for the forum so stuck it on a website:-
https://oldelectronics.files.wordpre..._ua15opman.pdf