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The Vital 1250 is a class D amplifier designed to deliver 170watts per channel (x12) at 4 ohms impedence.
There is however a number of these which are starting to come through with amplifier modules that fail.
There are 6 stereo class D modules using the TDA8970 design.
In breif the issues are down to the transformer secondary windings delivering slightly over spec voltage to the modules. Over time with the audio sense active this initial pulse from the transformer at power up sees off the amplifier chip and in many cases damages the PCB links between the double sided print making it impossible to remedy the exsisting module, so replacement is the only option.
The transformer on this unit is unique to this model and give 6 pairs of outputs for the 6 modules supplying 2x 29V AC which when converted to DC is around 41Vdc to each module, this can surge up on power on for a split second.
The TDA8970 is designed to take an absolute maximum of 39V and there is little or no protection on the output stage to stop a DC output occuring on the speaker outputs.
My therory is that this will be only the case for UK owners on a 240v mains supply as the tollerance may be acceptable for USA 110V users.
I have repaired these units by replacing all 6 modules with better units that have additional output protection between the TDA8970 and the speaker outputs. also adding resistors to the supply rails to help bring them in line with the correct tolerance and give longer life.
I am an engineer at MusicView Services and we speacialise in high end audio products and profesional music sound equipment.
I hope this helps someone with this amp, these problem will be specific to this model and should not be considered to relate to anything other than the Vital 1250.
It is possible that the fuse was blown due to a surge and replacing it will resolve the problem, but I wouldn't expect it. Usually when the main fuse blows, the primary stage of the power supply has a problem and the replacement fuse will blow as well. This is not a cheap amp and I would suggest that it be checked by a service tech. A few quick measurements internally can determine the likely fault and should not cost too much as an estimate fee.
you are actually not bi-amping the unit, you are bridging the amp. this really only works as long as all channels produce equal power. next the bad news is that typically home stereo amps are not wired internally to bridge channels.
bi-amping a speaker refers to connecting on channel to the highs and on channel to the lows. the receiver would need to be be able to process the outputs via a crossover network to split the frequency range in half so the appropriate frequencies went to the correct speaker.
please check first your input source and confirm it is ok.-check speaker button is pressed(if you have one)-speaker cables are connected firmly-from amp side and speaker side-check mute button(also if you have one)is not pressed.-make reset for your system(power off and on). if all above can not fix your problem you have to ask for help from service center.
Old amps with no display (no computer) are repairable for ever, but
when the display goes out like in yours - it is pretty much not
economically repairable. You can look inside for any obvious
damage (black or blown parts) but thats doubtful. Check the
voltages on the power supply. Should find 5v, 12v maybe a
negative voltage. Could have lost a voltage regulator in the
power supply causing the digital circuits to be down. good luck