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About tonypacheco

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  1. I have an old model acro tech 2400 amp whose serial no is 9030 221900. It has a main board no D6978-7. Some diodes keep shorting and I do not have the schematic diagram for this particular range. Would appreciate if any one could help
  2. would appreciate if you could recomend a support guy who could help out For the time being I have put them into a forced high voltage mode but I frankly do not like to use the amps in this fashion
  3. still stuck with the 5000vz nothing seems to work the control voltages -BI2 and +BI2 seem to be fine but the voltages on pins 5&6 0f U708B do not change as they should. Resistors R740,R737,R738,R741 R739,R745,R746,,R793 ICs U708,U709,U711 have been checked. U710 has been removed. Q711 and c737 have been checked with no positive results. the amp ch2 remains stuck in high current mode.. only when R742 is put in will the amp go into low current mode. I am begining to suspect that the fault could be PCB leakage at the terminals of U708B Sadly I have three amps down in this condition
  4. I handle almost the full range of crown amps. Of late I am having a problem with the VZ circuitry on three amps that remain in low lock position. The switche has been checked and if a 4K7 resistor is put in place of R712 than the amp remains locke in the high voltage mode. I have a problem in trying to troubleshoot in this area and would appreciate if someone could help with 1) what reference point to use 2)voltages to expect and how to isolate the faulty component regards Anthony Pacheco