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About dannyavila

  • Birthday 01/25/1968

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  1. Hola Marcos. Si el amplificador prende, muestra la pantalla de bienvenida y se apaga, ya sea con o sin altavoces conectados a sus terminales de salida, es porque tiene un canal da?ado y el voltaje DC de alimentaci?n de los transistores de salida averiados alcanza a los parlantes durante el encendido, dan?ndolos en el acto. Las reparaciones del XTi no son complicadas, pero deben ser hechas por personal calificado porque incluso la manipulaci?n representa un riesgo de electrocuci?n (sus disipadores de aluminio expuestos est?n electricamente vivos). Saludos,
  2. Just a couple of advises. When using the amp in Mono/Bridge mode to link both channels' input signals but keep the loudspeakers wired as Stereo, Channel 2 Loudspeaker's wires should be reversed to match the phase of the material in that output binding posts. And to reduce the excursions of the amp beyond its RMS power output, you could buy an install a PIP-CLP to limit the Clipping effect on the output waveform. It's worthy at all. Cheers!
  3. Saludos Alberto. Son muchas las causas de este sintoma. El indicador ODEP se enciende si no hay ningún problema tras la rutina de revisión del sistema. Desde un fusible quemado hasta la falla de transistores de salida pueden evitar que el indicador ODEP de un canal se encienda. Con el amplificador encendido, sin las cubiertas y después de revisados los fusibles, verifica que el voltaje de ambos disipadores de calor (positivo y negativo, electricamente vivos) tengan voltajes simétricos. En el MA1200 deberían ser unos 42~50Vdc en cada uno, medidos respecto al terminal negativo de salida del canal afectado. En el sitio Web de la marca dispones de material de soporte técnico para reparar tu amplificador, incluyendo el Manual de Servicio y esquemáticos para las varias versiones del MA1200. Manuales de Servicio Macrotech Saludos,
  4. Hello. I've found this problem related to some corroded and missing cooper traces in the PCB board, specifically around the Input Mode switch, and caused for dust/dew accumulation under the switch or in the edge of the PCB board, close to the back cover. Cheers!
  5. Well, sometimes dust and moisture accumulations caused by the fan's air flow going directly over the output board and some components causes a "missing track" condition when some part of the cooper traces just disappear in very little parts and interrupting the connection between components. It is common to the area surrounding the Dynamic/Static balance trim pots and under the ribbon connectors. If this is your case, after restoring the damaged cooper traces, try to apply a weather proof synthetic coat (3M™ Novec™ Electronic Coatings for example) sprayed over this section to avoid this problem again. Basis and Emitter PINs of some output devices can get loosen solderings caused by vibrations and board stress so you should check those soldering spots. But if you have a damaged power output device, the story is quite different and you'd better to send your amp to an authorized service center. Regards...
  6. Hi Gustavo: If the amp's sine wave negative side "disappears" at certain power level, it could be caused by an output current control circuit defective part. Did you check all the 0.33 Ohm/5 Watt output resistances, Q107-108 and Q124-125 BJTs or U104 (MC33079) conditions? In some cases, a missing cooper trace in the main board around the "Mode" switch area caused this symptom to appears randomly. Kind regards,
  7. Hi Smithers; The devices located inside the yellow squares are the amp's main Bridge Rectifiers. Since the channel main transformer's secondary wires goes directly to this semiconductor, its is possible that one if its four internal diodes is damaged and causes a short circuit condition. There are some other test to find out what is wrong with your unit but the reasonable thing to do here, if the problems remains the same after buying the new F100 board, is to take your amp to a qualified tech service center. There are potentially lethal voltages inside the unit and if you don't know where to touch you may be exposing yourself to an electrical shock hazard. Best regards.
  8. Hi Mvdrums: You'll need a PIP CLP input card to avoid "The Red Light" on clipping. The amp's signal level indicator (green LED in the front panel) goes full bright when Clip condition appears so you should set your processor's limiter threshold to avoid it. Clipping threshold in power amps is related to loudspeaker impedance and power source nominal voltage. The amp gets a sooner Clipping condition at lower impedances and at main power sagging caused by loses in the power wires. Plus this, there's an audible distorted sound at Clipping in almost any amplifier. Regards. Dr. Clip.
  9. Well, many things inside the unit may cause this abnormal behavior but there are three common problems in the MA5000VZ. The amp melts down the Full-Bridge rectifiers on heavy load conditions, the leads of the output devices get lose from their soldering spots (transport vibration?) and some missing tracks in the Power Output module. In your case, it looks like a Power Output device failure on just one of the steps since damaged output devices in both sides of the module blows out the channel main fuse the first time the failure appears. So the full-bridge rectifier will do. The PCB tracks failure in the Power Output PCB board caused by the dew/dust accumulation is usually located in the "Balance" circuitry area disabling the pots controls but this failure allows the amp to act like it turns On (Red LED steady) but the channel signal LED remains On and there's no sound at all. On any case, your amp requires Crown authorized tech service. If you are located in USA you'll find an authorized service center close to you in this link: or may contact Mr. Dave Engstrom ( dengstrom@crownaudio.com ) at (01)-574-294-8224. Best regards and Happy Hollydays.
  10. Well, the MA3600VZ and the MA5000VZ shares many features and are the class AB+B (VZ) devices of the Macrotech series . But these "small, almost insignificant increase in power" (700 watts more each channel) are achieved by implementing two toroidal Hi efficiency 3.5 KVa transformer, Clip/IOC Iload/Ilimit amp and speaker protection circuitry, two selectable attack speed (fast/slow) Clip limiter, selectable sub-sonic filter (LOI), variable speed fan (one per channel), full ATMEL PIP module interface, class AB or AB+B selectable mode and 100 - 250 Volts 50/60 Hz selectable operation range. Personally I think the MA5000VZ is indeed the best amplifier ever built. Regards.
  11. Let's start by saying that this is a personal criteria: Well, many pro guys use to say that the best class to power high freqs is AB. The reason, the power is in there all the time and the peak/transients involved in this freq area are too fast to make a class-H amp to react at time to activate the second (third...) voltage stage so the amp "cuts" (limits) the upper part of the sound due the lack of power and once the CLIP appears. I should think that this concept is in the past and today's technology offers improved applications in the composed/mixed signal amplification area, but personally, I'm not ready to leave my highs on digital (D, I, TD, whatever class) amplifiers so I still trust in the MacroTech class-AB gear. Of course, the amplifier quality has everything to do with this criteria. You won't expect the same sound accuracy coming out from a Crown amp in the sound produced by some Chichumazu ® amp. The class H (AB + and Digital class (class D, TD, I) amps are more efficient to handle heavy loads at low impedances in the Low/Subs frequencies cause having dual or more stages power supplies, they use only the power that they need; less power wasting, less heath. I hope you can find any use on these words. Regards.