Hi everyone,
got this old lenco R600 Stereo Receiver. It has worked good for all these years. Last 31st December i used it for a few hours to listen to the music.
Was working good, except for the central pot that adjust the volume and balance, if i move it i can hear some sparkling sounds, maybe the component is old and need to be replaced. Tried contacts cleaner, better but not perfect.
Anyway the day after i tried to power it on but no output sound.
It has 2 outputs: Speaker A and B, each one for 2 speakers L-R.
Usually when i select Speaker A or B i can hear the relay that powers on, this time no sound at all.
So i've disassembled it, and i've found out a very strange thing.
One pin of the coil of the relays is soldered to -40V line (tested, -40V constant).
The other pin of each coil is enabled by the control in the front of the receiver (speaker A, Speaker B).
When i power on the receiver, and i enable Speaker A for example, i have only 8VDC between the pins of the coil (same thing for Speaker B anyway), but the relay is a 24VDC one.
If i wait some time (1 min more or less) the voltage slowly increasing, and when it reaches 14V the relay powers on and all is working perfectly (both speaker A and B).
If i disconnect the power, i wait several minutes and i try again, i have to wait another minute to have the relays ON.
If i disconnect the power but i power it on again after 20 sec for example, all is working good, i suppose because the capacitor remains charged.
Looks like a capacitor problem...i replaced the ones on the left of the mainboard without success.
I didn't replace the 2 big capacitors, but i suppose their only purpose is to filter the AC power.
I don't know what to do, because i can't even find a schematic.
Maybe is due to a bad transistor? Please help, thanks
got this old lenco R600 Stereo Receiver. It has worked good for all these years. Last 31st December i used it for a few hours to listen to the music.
Was working good, except for the central pot that adjust the volume and balance, if i move it i can hear some sparkling sounds, maybe the component is old and need to be replaced. Tried contacts cleaner, better but not perfect.
Anyway the day after i tried to power it on but no output sound.
It has 2 outputs: Speaker A and B, each one for 2 speakers L-R.
Usually when i select Speaker A or B i can hear the relay that powers on, this time no sound at all.
So i've disassembled it, and i've found out a very strange thing.
One pin of the coil of the relays is soldered to -40V line (tested, -40V constant).
The other pin of each coil is enabled by the control in the front of the receiver (speaker A, Speaker B).
When i power on the receiver, and i enable Speaker A for example, i have only 8VDC between the pins of the coil (same thing for Speaker B anyway), but the relay is a 24VDC one.
If i wait some time (1 min more or less) the voltage slowly increasing, and when it reaches 14V the relay powers on and all is working perfectly (both speaker A and B).
If i disconnect the power, i wait several minutes and i try again, i have to wait another minute to have the relays ON.
If i disconnect the power but i power it on again after 20 sec for example, all is working good, i suppose because the capacitor remains charged.
Looks like a capacitor problem...i replaced the ones on the left of the mainboard without success.
I didn't replace the 2 big capacitors, but i suppose their only purpose is to filter the AC power.
I don't know what to do, because i can't even find a schematic.
Maybe is due to a bad transistor? Please help, thanks
Comment