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About envisionelec

  1. CE4000 Heavy Current Draw

    Good Afternoon, There might be a couple of issues going on in the amp. There might leaky capacitance in the brown out circuit. Try checking C49 and C72. The current draw might be a little more difficult. You can check and see if the slugs in the output tuning coils have dropped out or vibrated all the way down the coil. These are 200k and 250K notch filters and if these are out the Underlap and Overlap adjustments will be out of line and the amp will draw heavy current. Hi Kevin - thanks for your reply. I realize that it's rather counterproductive for a company to hand out fixes on a public forum... That said, the amplifier does actually work with the PFC circuit bypassed and brownout protection disabled. While I don't disagree that the notch filters will play a part in causing a heavy current draw due to cross-conduction, I would think that would be a symptom that would show up any time the amplifier was operating. Additionally, since SMPS is not drawing the some 50A of current through it's primary (thus latching the overcurrent protection), I don't believe it's an audio-side issue. After a little soul searching, I've talked with the owner and we've agreed that it's going to be more worthwhile to have it sent in. Besides, when we get the repair bill back, I will know what to look for in the future. It's all about learning. Thanks again!
  2. CE4000 Heavy Current Draw

    Anyone, please?
  3. Hi, I'm new to the forum but not new to audio amplifiers, their design and repair... I have a decent amount of experience with the CE4000, having done a half dozen of them for one client (output FETs, RF bypass caps, VIPer, burned traces, etc). I have one on the bench (Ser#A107030) that exhibits a heavy current draw right after the inrush relay kicks in. I am running a BK variable isolation transformer with ammeter for troubleshooting. It will stutter a bit at 1.5-2A for about 200mS then pegs out at 6A and pops the slo-blow fuse in the iso-transformer if I let the amplifier remain in this condition. I temporarily removed the PFC transistors and bypassed the PFC inductor with a wire jumper. The modulator would come up and phase relationship between H Bridge drive was OK. (I have Brownout override jumpers installed). Although rail voltage was decreased to ~+/-50V due to PFC bypass, the amplifier operated normally with low (<5mV) DC Offset appearing at the speaker terminals. The audio section seems to be in fine working order as does the SMPS (low voltage). Following the service manual, I have connected an external power supply to the PFC controller and receive expected changes, however I cannot test it fully because the FETs are removed. All VIPer voltages are normal. I have also tried swapping PFC boost inductors with no change. PFC gate drive looks good and PFC IXYS FETs test OK. I've temporarily replaced the primary filter caps which made no difference in symptoms. Have their been instances where the transformer windings will break down at 400V but not 185V (PFC active vs inactive)? Any clues where I can look next? I know the next answer will be "send it in", but I am confident that I can repair this. It's a challenge for me - you won't lose me, technically. I guess I should add that I do not work at a "shop" and am not making any money from this.