Lamp limiter.

[catch29]

I've decided to have a preliminary look at my Claude Paz Cadet2 record player. The limiter glows 1/2 strength (100w bulb), is the drive motor effecting it?, should I disconnect it to see what the amp bit is actually up to?.

[ppppenguin]

We don't know anything about this record player. Presumably one like this: https://www.radiomuseum.org/r/claudepaz_cadet_2.html

Does it have a mains transformer for the amplifier? Or are the supplies derived from a tap on the motor winding?

A 100W bulb should barely light at all with a small amplifier like that.

[Diabolical Artificer]

Open it and investigate, but motors need a lot of current to start up. A thorough visual inspection should always precede a power up,never power up anything blind. Also check the fuse, it tells you a lot.

Andy

[Murphyv310]

Hi.
I'm with Andy here. As a qualified TV engineer during our city and Guilds practical work the lecturer would repeat many times use your eyes ears and nose before applying power to any repair.
In the case of vintage repairs you have no idea, of what condition the item is in if you don't "look" first, often the smell of burning can remain for many years as can dampness, you may see snipped components, wires etc so look in the first instance.

Lamp limiters are a basic way of reducing available current to an item, they are far from perfect though. Start with a 25 watt bulb this reduces current considerably and gradually work up if the bulbs are very bright, stop and investigate. Look for shorted mains filter caps or other maladies. Use your nose for burning smells and look for wisps of smoke remember keep safe it's mains you are working with, the bulb should be in the live feed.

[Mike Watterson]

Lamp limiters are of most use on Valve TVs, and secondarily on series heater radios after you've replaced obviously bad caps etc. Not much use for an amp like this.

It's common for valve heater to be fed from the motor and HT is rectified mains. So live.

Separate motor and run it direct if using a limiter. But reform HT and electrolytics with a 30V current limited PSU ( a few mA) with valve out and no mains. Replace paper caps on anodes to anywhere. They can have metal or composite cases, not just waxed card. Reform and check cathode electrolytic by disconnecting cathode end; if it's leaky the bias is excessive. This circuit is so simple a limiter isn't needed if the parts are checked.

[ppppenguin]

The RM entry says this player uses an ECL82. If this is correct, the heater is unlikely to come from a tap on the motor. Of course the RM entry could be wrong. If the valve is actually a UCL82 then its heater is probably from a tap on the motor.

In any case the player could easily be live chassis (strictly speaking chassis connected directly to one side of mains) and thus hazardous if you don't understand what you're doing.

[catch29]

Thank's for the advice Mike, and everyone else. I did all the preliminary checks and I'm very safety aware, not wanting to electrocute myself now I've made it to this ripe old age!. I'll take time with it and be systematic, re-cap etc, a couple of the big cap's look very dodgy. I may put this on the back burner for a while. I have nine Heathkit amps and tuners I need to get running to add to my collection, but first I'm going to re-cap and 'mod' a pair of Kef Concerto's and finish a pair of 'hybrid' speakers. Sandy Denny sang "who knows where the time goes?" nuff said.

[Mike Watterson]

The RM entry says this player uses an ECL82. If this is correct, the heater is unlikely to come from a tap on the motor. Of course the RM entry could be wrong. If the valve is actually a UCL82 then its heater is probably from a tap on the motor.

In any case the player could easily be live chassis (strictly speaking chassis connected directly to one side of mains) and thus hazardous if you don't understand what you're doing.

I agree with both of those points. They did have motors for HT on transistor amps. I have one. Also live chassis!
All the simple valve record players I've seen use U series, so I did wonder at the ECL82 as a transformer added a lot of cost. Though some radios used HT from the mains and an autotransformer for the heaters.

[catch29]

            Yes it uses an ECL82 powered off the main transformer which looks a bit battered and I will need to check also the two big .5mf caps in parallel look a bit melted. Good fun.

[catch29]

  cadetatwork.zip (Size: 3.89 MB / Downloads: 5) I'm having a 'mare' downloading pickies