Dynatron Henley RG33W radiogram

[peter_sol]

If you replaced the fuse,did it blow again?

[Vintage84]

No, the fuse is fine (and the bulb over the record player still operates with the piano keys).

[julie_m]

So you have continuity all the way through the power lead, on/off switch and transformer primary? Then the next thing to test would be the secondary side of the transformer.

With the set switched off, connect your meter, set to 20 V AC ~, to pins 4 and 5 of any valve (count clockwise from the gap, because you are looking at the underside, but it will be obvious anyway; there will be two fairly hefty twisted wires, linking pins 4 and 5 of all the valves to each other), preferrably using crocodile clip adaptors so you can keep your hands well clear. Then switch the set on.

What voltage reading do you get? (Anything between 5.67 and 6.93 is good.)

[Nickthedentist]

Originally Posted by julie_m

So you have continuity all the way through the power lead, on/off switch and transformer primary?

...unless it's the lamp that's giving us that reading. Repeat the test with the bulb removed.

[Vintage84]

Originally Posted by julie_m

With the set switched off, connect your meter, set to 20 V AC ~, to pins 4 and 5 of any valve (count clockwise from the gap, because you are looking at the underside, but it will be obvious anyway; there will be two fairly hefty twisted wires, linking pins 4 and 5 of all the valves to each other), preferrably using crocodile clip adaptors so you can keep your hands well clear. Then switch the set on.

Thanks Julie - I will try this in the morning and let you know how I get on

Originally Posted by Nickthedentist

...unless it's the lamp that's giving us that reading. Repeat the test with the bulb removed.

Same result with bulb removed

[Nickthedentist]

...which is good, as it means that the primary of the transformer really is OK.

[Vintage84]

Originally Posted by julie_m

With the set switched off, connect your meter, set to 20 V AC ~, to pins 4 and 5 of any valve (count clockwise from the gap, because you are looking at the underside, but it will be obvious anyway; there will be two fairly hefty twisted wires, linking pins 4 and 5 of all the valves to each other), preferrably using crocodile clip adaptors so you can keep your hands well clear. Then switch the set on.

I'm not able to get any reading from the back of the valves.

[Station X]

Trace the wires from pins 4 and 5 of the valves back towards the mains transformer. Then check the voltage directly on the transformer.

[Vintage84]

Originally Posted by Nickthedentist

Note that the RG33S seems to be an entirely different beast, being all-transistor. Also, the RG22/3 is a lesser machine with a mere 5 valves, and as Graham implies, the "Cliveden" is the RG23 not RG33 as Paul describes it in the index.

OTOH, the RG21 is described as using 9 valves. Is your line-up: ECC85 ECH81 EBF89 ECC83 EM84 ECL82 ECL82 ECL82 ECL82?

The ones I can easily read are: 4x Ecl82, Ecc83, Ebf89 and an ecc85

[Station X]

Originally Posted by Nickthedentist

As a start, unplug the machine, set the meter to its lowest ohms range, connect the probes to the plug's L and N terminals, and see what the meter says both with the power switch on and off.

If the primary of the power transformer, its wiring, switches and fuses are OK, you should read a few tens of ohms with the switch on, and infinity (1- on a digital meter) with it set to off.

N.

Another thought about this. If the turntable motor is connected directly across the mains transformer primary (as it is in the RG21 model) this test will be invalid. In the RG21 the motor connects via a plug. If your model is the same unplug the motor, unscrew the lamp and repeat the test.

[julie_m]

So, we think power is going into the transformer; but it isn't coming out the other side. Can you get some good, clear pictures of the transformer and the wiring immediately connected to it?

[Vintage84]

Originally Posted by Station X

Another thought about this. If the turntable motor is connected directly across the mains transformer primary (as it is in the RG21 model) this test will be invalid. In the RG21 the motor connects via a plug. If your model is the same unplug the motor, unscrew the lamp and repeat the test.

Same result with the turntable disconnected.

[Vintage84]

Originally Posted by julie_m

So, we think power is going into the transformer; but it isn't coming out the other side. Can you get some good, clear pictures of the transformer and the wiring immediately connected to it?

I've pulled the chassis out of the cabinet now, so can hopefully can get to the parts required. It seems to have 2 smaller ones in the chassis and then a large one (with the fuse) which is located on the bottom of the cabinet.

Which one do I need to check the voltage of? The large one seems to have some substance coming out underneath...

['LIVEWIRE?']

Vintage 84, apologies if i
I'm stating the obvious, but your meter should be set to a low ac voltage range, when checking the heaters(pins 4 & 5) 'E' series valves, such as those in your Dynatron, are run from nominally 6.3vAC.

[Vintage84]

I was just using the auto AC setting on my multimeter as it doesn't allow voltage to be set. I haven't used this in a few years so let me know if that's not what I was supposed to be using!!

[Station X]

The smaller transformers are the output transformers. The other one is the mains transformer.

[ms660]

Originally Posted by Vintage84

Which one do I need to check the voltage of? The large one seems to have some substance coming out underneath...

I don't have a schematic for your unit but if you want to check the valve heater supply output voltage at the transformer then that transformer will be the large one shown in your pictures.

With the unit unplugged from the mains supply try and trace the wires from pins 4 & 5 of the valves back to that transformer, those will be the heater supply, in some radios etc there are two wires one from pin 4 and one from pin 5 running back directly to the transformer, in others only one wire from either pin 4 or 5, if it's the latter case then one of the valve socket heater tags will be connected to the chassis as will one of the heater supply tags at the transformer. Once you've identified the correct tags on the transformer you can apply power and do the heater voltage measurement but do it reasonably quickly as that transformer might have been a bit stressed by a fault judging by the wax on it.

AC Auto range will be ok for measurements with your meter.

EDIT: Woops, my post crossed.

Lawrence.

[Vintage84]

I've traced these cables back to the main transformer and I'm not getting any output reading from the multimeter

[Vintage84]

So presumably a new transformer is required as the input into the transformer is fine, but there is no output.

[Station X]

One possibility is that there's a short circuit across the heater supply line. Remove the valves and measure the resistance looking into the transformer.