User manual AUDIO TELEX DCM250

[. . . ] The DCM250 also features a DC battery trickle charge facility, autosensing frn cooling, plus overload, short circuit and over tmperature protection. The maximum recommended load for the DCM250 is 40 ohms. lnitial Set Up There is an unlabelled screwdriver adjustable output level control located centrally on the front panel of the DCM250. will increase the power output, turning this control in a counter-clockwise direction will reduce the power output. [. . . ] Cooling Fans (Air lntake): The cooling fans (two installed in the case of the DCM250) are temperature sensitive and only switch on when the temperature of the DCM250 had reached a pr+determined range. The fans will stay on and only switch off again once the te, mperature of the DCM250 has frllen below a pre-determined level. So, the hct that the fans axe not operating at any time (and most noticeably to the operator at turn-on) does not mean that the amplifier is faulty in any way, just that it is operating within a temprature range that does not need frn cooling for adequate heat dissipation. If the DCM250 is operating continually at conservative levels and proper load conditions, it is possible that the cooling fans will not switch on at any time during normal operation. Whe, n operating, the fans cause air flow from the front to the rear of the DCM250. Continued noct page3 Amplifier Status Display WindOw: The status displaywindowhighlights the operating conditions Please refer to Figure #l of the DCM250. on the back page ofthis instruction sheet with nlmerical reference as follows: Hig!Temperature: This red LED glows if the fan has failed and the amplifier has been shut dov, rn by its, te, mperatwe control circuitry. If this LED is glowing and the fans have not failed, it means that the amplifier is operating in an ambient environment that it naturally too hot for fan cooling to make any difference to the temperaturi of the amplifierl Power: pres, lroe This LED glows green of a DC supply voltage if AC power is switched on to the DcM250. Note that this LED does not indicate the MainS FailUre: The LED glows red if there is a failure in the AC mains power supply. However, this LED glow if there is a DC supply voltage present. If no DC supply voltage is present then this I. fb wiff not glow. will only Output Level VU A 10 segment LED VU meter is provided to give an indication of the output signal level of the DCM250 from -25 to +3 dB. For normal operation the LED's should oscillate in and out of the red zon!. If the LED's in the red zone are lit continually, then the output level control (or the level of the input sigrral to the DCM250) should be adjusted to reduce the output level. Too much output level can cause distortion and positt" Iu-"g" to the connected speaker ileter: systern. Rear Panel Connections Please refer to Figure #2 on the back page of these instructions with numerical refere, nces as follows: 3 pin IEC' AC mains power The operating voltage is 240 vAC @ 50 Hzor l l0 vAc @ 60 trz. The AC power voltage level is not externally user selectable but is factory pre-set (via transformer selection). [. . . ] The value of the fuses is l0 Amps slow blow. Please ensure that the AC power switch is in the 'ofr position and that the mains power cord is disconnected before attempting to check or replace this frrse The input to the DCM250 is transformer balanced @ The configrnation of both sockets is as follows: pin #l-earth;-pn #Z-agtive (high, +); pin #3-active (low, -j. The output socket is to allow the original input signal to be fed on to another amplifier. [. . . ]