10-03-2010, 03:54 PM
I decided to calculate, what might be the extra current, that causes the twitter coil to become hot. Let's assume extra 50W are dissipated in the coil. So, 50W=I*I*R, were R=670 Ohm, so there is 0,27A of extra current. The coil is connected to upper chassis via resistor N 69 - 500 Ohm. This is 1/2 W resitor and 0,27A would cause 0,27*0,27*500 = 36W. This power would burn the small resistor, but it is cold even after 1 hour of the radio "on". That means the upper chassis is excluded. Not guilty.
After I checked all sockets, all wires and connectors, all trasnformers and coils - I started to hesitate - may be this twitter coil should be that hot? Remember the 4-section resistor N 163 (and N165), mounted on the chassis? It is always very hot...
So I ask the owners of 38-690 - can you please touch the back of the twitters after e.g. 40 minutes of operation? Are they both cold, or one is hotter, than another one? It is safe to touch the back of the speaker even with the radio "on" - it is grounded. But of course for safety reasons it should be done with the radio "off" for sure.
Well, thank you very much in advance, you can save my brain from exploding!
Leonid
After I checked all sockets, all wires and connectors, all trasnformers and coils - I started to hesitate - may be this twitter coil should be that hot? Remember the 4-section resistor N 163 (and N165), mounted on the chassis? It is always very hot...
So I ask the owners of 38-690 - can you please touch the back of the twitters after e.g. 40 minutes of operation? Are they both cold, or one is hotter, than another one? It is safe to touch the back of the speaker even with the radio "on" - it is grounded. But of course for safety reasons it should be done with the radio "off" for sure.
Well, thank you very much in advance, you can save my brain from exploding!
Leonid
