tube (valve) help

[rematzz]

hi all, i'm restoring a regentone radiogram that isn't playing any sound from the radio and the record player, i have replaced one of the tubes, but it didn't work.

the only way i can test a tube is with a multi meter, my findings are with the tubes listed, i tested the pins clockwise.

it has 6 tubes they are:
ECC85 pins 4+5
ECH81 pins 4+5
EF89 pins 1+6
EABC80 pins 4+5
EL84 pins 4+5, 1+6
EZ80 pins 4+5

does this mean that EF89 needs replacing?
the EL84 results are from the replacement, does these results mean that its a dud?

thanks for any help in advance

 

[Alec_t]

Er, where are the results of your tests?

 

[rematzz]

where it says pins, with the multi meter the needle went to the max when certain pins where touched with plus and neg of multi meter

 

[Minder]

Would appear the audio section is not working so start in the audio output section, a meter lead or touch a probe to the grid should produce a hum or click, especially if you place your finger on the probe.
Ensure the anode/power +v is present.
M.

 

[duke37]

If you go on vintage-radio.net/forum you can probably get a circuit diagram for £2 which will give the working voltages. Note that these are lethal.
There is a possibility that the chassis is live, if so it should only be run through an isolating transformer.
It looks as if it is a standard circuit covering FM, LW and MW.

EL84, B9A -16
1. Internal connection
2.Grid 1
3.Cathode, grid 3
4.Heater
5.Heater
6 Internal connection
7.Anode
8.Internal connection
9.Grid 2

If the capacitor feeding the grid is leaky, it could ruin the valve, output transformer and mains transformer. The grid should stay near 0V.
The cathode, if I remember rightly should be about 7V.
It is unlikely that the valves are faulty, dodgy switches are much more likely or leaky electrolytic capacitors.

My method would be to measure the valve voltages and make sure these are somewhere near. It will not work properly if the voltages are wrong.

EF39, B9A-36
1. Screen
2.Grid 1
3.Cathode
4.Heater
5.Heater
6.Screen
7.Anode
8.Grid 2
9.Grid 3
There should be a connection between 4 and 5 to drive the heater.

Best of luck, stay safe.

 

[rematzz]

would you say that the ef89 needs replacing because there isn't a connection between the heater pins

 

[Alec_t]

If the resistance measured between the heater pins (4 and 5) of the EF89 is not less than or equal to about 30 Ohms then the valve is dead.

 

[GPG]

If the resistance measured between the heater pins (4 and 5) of the EF89 is not less than or equal to about 30 Ohms then the valve is dead.

With the valve unplugged

 

[GPG]

it has 6 tubes they are:
ECC85 Double triode
ECH81 Oscillator converter (radio)
EF89 Prob IF amp (radio)
EABC80 Detector amp (radio)
EL84 Audio output Shoulhave HT on Anode
EZ80 Power rectifier should have HT on Cathode.

 

[GPG]

Have you got a model number?
http://www.radiomuseum.org/m/regentone_gb_en_1.html

 

[rematzz]

thanks everyone for your replies,

it is a regentone arg 80, on the inside it has the date 27 march 1956

 

[GPG]

http://www.radiomuseum.org/r/regentone_arg80arg_8.html