hot trafo

[inecik]

Hi,forum
I am repairing a schaub lorenz goldy 3133 radio.I turned on the radio, there is no sound, there is light on the tubes and importent thing that; the trafo is very hot and there is smoke . immeditly I turned off the radio. for you where will I check FİRST.

[eabc]

Hallo,
An der Anodenspannungswicklung des Netztrafos sind zwei Entstörkondensatoren gegen Masse gelötet, raus damit, das könnte das Problem beheben, falls es für den Trado noch nicht zuspät ist.

[olli0371]

Hi,

there are several possibilities for hot transformer:

1. Transformer is broken - short circuit in primary or secondary winding
2. too high current on secondary side of transformer
3. short circuit in the radio

To find the root cause for your problem please disconnect the secondary winding completely from the circuit of the radio (before doing that, mark up all wires that you are able to connect them later correcly (-; ).

Then use a normal 220V / 60W lamp as a resistor and connect the lamp in serios to the Radio.

The circuit should be like this: Mains -> lamp -> Radio

If you now power on the lamp should be nearly off. If the lamp is on as normal than the transformer itself is the problem (broken).
I do not hope so.

Try that and you will see what happen


Bye
Oliver

[inecik]

Hi, I am a new restorer so I didn't understand clearly. 220V current have two wire ,and where will I connect that wires on the lamp.

there are several possibilities for hot transformer:

1. Transformer is broken - short circuit in primary or secondary winding
2. too high current on secondary side of transformer
3. short circuit in the radio

To find the root cause for your problem please disconnect the secondary winding completely from the circuit of the radio (before doing that, mark up all wires that you are able to connect them later correcly (-; ).

Then use a normal 220V / 60W lamp as a resistor and connect the lamp in serios to the Radio.

The circuit should be like this: Mains -> lamp -> Radio

If you now power on the lamp should be nearly off. If the lamp is on as normal than the transformer itself is the problem (broken).
I do not hope so.

Try that and you will see what happen


Bye
Oliver

[olli0371]

Hi

the wiring should be like this:

220V Phase -> lamp input -> lamp output -> radio input -> radio output -> 220 V neutral.

regards
Oliver

Check Wikipedia for serial connection

[Phalos Southpaw]

Schematically like this:

[inecik]

O.K I will try.

[inecik]

hi, forum
I just measuremend afew voltages on EZ80 tube and results;
there are 235VAC on pin7
but there is no voltage on pin1.
the trafo is faulty?if it is O.K, I will try to replace an another trafo and bridge rectifier because another trafo has single secondery(215VAC) and 6,3VAC.

[eabc]

Hi Inecik,
es wäre schon nicht schlecht wenn du auf gegebene Tips antwortest, die EZ 80 sollte vom Netztrafo 2 x 275 VAC erhalten, diese Wicklung hat einen Mittelabgriff der an Masse gelötet ist. Mache mal eine Durchgangsprüfung und enferne die beiden Parallelkondensaoren bevor der Trafo abbrennt.

[olli0371]

Hi,

did you disconnect all secondary wiring (including the capacitors from secondary side of transformer to chassis as written by EABC) of the transformer and connect the lamp in serious as shown by Phalos?


Regards
Oliver

[inecik]

no,I will try to connect serious the lamp after.
I measuremend when trafo secondry wires connect on the radio.

[inecik]

now I looked interesting thing that; when the EZ80 on the socket, pin1 connect to ground but when EZ80 isn't on the socket , pin1 no connect to ground. EZ80 is faulty?

[olli0371]

I think you didn't understand. The sense of the lamp is to protect you transformer. If you proceed like you do at the moment you will kill the transformer for sure.

Oliver