TELEFUNKEN TRX 3000

[telefunkenphilips]

Hello EVERYBODY

Please help me:
I have one Telefunken TRX 3000
It get problem each time I turn on the device:
If I hearing the switching of relais when I power on then everything is ok, sound is very good, all working all day if I not power off.
But if another time I turn on but not hearing the switching of relais , then the sound is terrible, all noisy in all channel in all mode : aux,fm,monitor,..
4 lamp signal indicator is at high level and sound noisy
So what is problem?


Thanks and best Regards

[__diz__]

Hello

I'm confused about your statement: "I turn on but not hearing the switching of relais, then the sound is terrible".
If the protection relais don't switch, you normally don't hear anything, because the loudspeakers are not connected to the power amplifier.

Regards Dirk

[jring]

Using Headphones maybe - does the relay cut the headphone out too?

OP please give more details...

Joachim

[telefunkenphilips]

sometime when i turn on but i am not hearing the switching of relais then sound is noisy terrible , 4 channel led indicator all are high level, then i have to turn it off
Somebody told me that i have to replace two big power capacitors but i do not know if it can fix

[jring]

Hi,

I have had a look at the service manual available from electro tanya - the download link is the little "Get Manual" below the preview picture.

What I can see is that there's 4 relais RS502 to RS505 being used to switch on the loadspeakers. They are activated by sth called "Einschaltverzoegerung" in german which should translate to time delay switch. Actually this looks like it is more than just a time delay but a protection circuit since it gets input from the power amp output probably looking for DC on the speaker out.

So we have to ask ourselves two questions:

- why do you still hear sound in the speakers if the relais do not switch? Have the relais been bridged by somebody? You should first check this and correct it by removing the bridge since DC will kill speakers pretty quickly.

- then you might get distorted or no sound even with the relais switching through - this is usually due to dirty relay contacts and probably was the reason for sb shorting them - so you might want measure those and if there's contact problems you need to clean the contacts or replace the relay.

- then you can try to figure out the occasional problem with the relais not switching after power up. Since the relais now just don't switch through you can then keep it on and measure for DC on the power amp output before the relay. If no DC is there you could measure the 18V (U7a) and 27V (U6) supplies - both are used by the protection circuit.

PS: one more question - does the overload light work and if yes, does it burn when you have the problem?

Joachim

[monoethylene]

i have to laugh right now..

telefunken philipp if there is a prob with the relay just check it..if you hear sth just check the amp..