Dansette Conquest Questions

[Skyman69]

Hi all.

This is my first post so be gentle!!

Right, I've just acquired a very nice Dansette Conquest, I've powered it up and the turntable works great (I've lubed it up and made a few adjustments) but there's no sound.
Taking it apart I've found that the two red wires that give 240V to the amp have been cut and the cartridge has been changed to a stereo one has been used as a line out via a 5 pin DIN plug, not very authentic.

The single valve amp looks OK apart from the transformer that resembles a candle, wax has poured out of the bottom and set.

So do I plug it in and see what happens? Or do I change the caps and take it from there?

Also, I have no idea what year it is or how rare because it doesn't have an illuminated badge, the BSR monarch mech has red controls and the cabinet is black and cream.

['LIVEWIRE?']

From your description, the transformer may be faulty so do not plug the player into the mains until it has been checked. The modification you mention may have been carried out not only to allow stereo records to be played, but because of the transformer fault, which made the internal amplifier unusable

[Skyman69]

Thanks for your reply.
That's kinda what I thought !!
What output is the transformer ? I notice that it has two secondary's.
Where can I get one from ?

[Station X]

There were several Conquest models. What is the valve line up and how many transformers does it have?

[Skyman69]

It's a single transformer with a single valve with what I can only make out is the number '82' as the rest has rubbed or burnt off!

[Edward Huggins]

This sounds like an early version using the relatively rare BSR UA12 deck c.1959.
It may also be one of the first Conquests to use the ECL82 amplifier. The mains transfomer is quite lightly rated, but I have never know one to overheat or fail. It's not easy to buy small mains transformers these days, a Member may have one, but it may not be faulty. The 2 secondaries will be for half wave HT and 6.3V heaters. You will need to take some voltage measurements first. Do leave the stereo cartridge in and bridge the channels so you can continue to use it in Mono.

[Station X]

This sounds like a Dansette Conquest Auto using the D/T Amplifier having a solid state rectifier and a single ECL82 valve. It obviously has an output transformer, but I'm not sure whether the HT and LT supplies are derived from a mains transformer or an overwind on the motor.

Service data is available here:-

http://www.service-data.com/product....15/1498/a11115

You could check the resistance of the transformer windings and perhaps measure HT and LT voltages with the valve removed.

[Skyman69]

Excellent.

I've just downloaded the service data, which will help greatly.

It says one of the windings is 6.3v but what it is other?

And where would I get hold of a replacement transformer as my one looks very 'dry'?

[Station X]

6.3 VAC is the Low Tension or LT winding which supplies the valve's heater and causes it to light up.

The other winding is the HT winding and is "probably" around 200-250VAC.

I'm confused though, because I don't know whether the player has a mains transformer or uses an overwinding on the motor. Only you can tell me that. A picture of the transformer/s would help.

Output transformers are relatively easy to obtain. Mains transformers are a bit more difficult to source.

[Skyman69]

It has a mains transformer, the motor is just powered straight from the mains !!!
The transformer had been leaking wax and it had set on the wooden base of the cabinet.
I'll check its voltage tomorrow

[Herald1360]

Before you give up on your transformer, try quickly powering it up in isolation (mains to primary, secondaries disconnected). If it doesn't show any signs of distress after half an hour or so, check its secondary voltages. If they make sense (6.3V or so and 200-250V or so) then dry and wax dripped or not, it's likely fit for further service. If it goes bang or lets out the magic smoke you're no worse off than you thought you were to start with! Just turn it off before it sets fire to anything else

If it is dead, there are usually second hand ex radio transformers (often complete PSU subassemblies) on Ebay which could be a cheap fix with a bit of ingenuity, or you could simply go for a cheap Chinese audio amp module just to get the player going if restoration as such isn't important.

[Station X]

Sorry to harp on about this, but the player should have an output transformer in addition to the mains transformer. Is the output transformer present or has it been removed?

[Skyman69]

Yes there's an output transformer as well.
The power transformer seems to be ok I think !!!
Unloaded I'm getting 7.9V and 279V

[Station X]

That's good news. Are you getting a DC voltage across the smoothing capacitors?

That's the 16uF and 32uF sections of the can capacitor.

[Skyman69]

Do you think the voltages are ok ?
I haven't done a DC test yet as I was going to change the Can cap first..
But I may take a risk and power it all up

[Station X]

Yes I think the voltages are OK.

Check the DC voltages on the existing smoothing cap and make sure it does not get hot and that mains the transformer shows no signs of distress.

I strongly recommend that you don't power it up until you've changed the 0.01uF capacitor on pin 9 of the valve. Failure of this component could cause serious damage.

When powering up monitor the HT voltage and switch off immediately if it drops to a low level.

[Skyman69]

Understood.
I've ordered a 0.01 and some caps to replace the entire can just to be safe.

[Skyman69]

Hi all
I'm going to the change to 0.01uf 400V capacitor and also change the 3 caps that are currently in the 'silver can' on the single valve amp board from my Dansette Conquest Auto.

Which brand / type would you recommend ?
I've heard that cheap ones give a different sound to more 'retro' type ones and where would you get them from ? As Google isn't very helpful at the moment.

Thanks in advance

[Boater Sam]

They all sound the same when they explode.
Please don't suggest that I could hear different sounds from different brands of electrolytics.
You are having a laugh aren't you?

[Skyman69]

I was searching for Capacitors and a few people have said that certain ones sound 'warmer' than others in valve amps !!!
So no, I'm not having a laugh but they obviously are.