I just received a zx2500.1 and it has a single shorted output. I removed the output and attempted to start the amplifier. All the power supply mosfets are good. Yet the amplifier just attempted to build a drive signal and shuts back down. It doesn't draw alot of current a fee amps when this happens. I surely would appreciate some guidance.
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I would recommend you remove all four output inductors, you will want to resleeve the leads with something more substantially. We would use a white coated nylon? sleeve, not sure what the product name is, someone may be able to chime in.
Look for any perforations in the red sleeves on the leads of the inductors. The inductor driven by the output that shorted may have perforations that allow the lead to short to the windings. It's also possible there are some burned windings are the core is cracked or damaged.
With the inductors removed you can check the drives to outputs. It's possible one of the drive boards is bad and causing the output to short.
Look for any perforations in the red sleeves on the leads of the inductors. The inductor driven by the output that shorted may have perforations that allow the lead to short to the windings. It's also possible there are some burned windings are the core is cracked or damaged.
With the inductors removed you can check the drives to outputs. It's possible one of the drive boards is bad and causing the output to short.
Some of the sleeving is fiberglass. There is also fiberglass with a silicone coating that doesn't fray as bad but isn't as conformable and may be a problem where the leads are barely long enough to get through the board. .
They are all well seated and have this red sleeve on them. Someone has attempted to repair this amplifier before and used multiple date codes in the power supply and output section. I'm going to be rebuilding both completely the correct way. Also two of the 100k resistors we're out of tolrence (replaced). All the inductors seem ok. I replaced the bad components and it Powers up. I will remove them and do it the correct way.
There is also a 3k3 resistor missing on the driver board someone haphazardly removed and sodered back badly.
Ok so further inivestigating i received information that the last owner had this repaired it blew caps and the outputs. So i must pull all the output inductors and replace the tips with what, where can i buy, what i need? Or just use a series type of shrink wrap for major electrical? i also need some excellent spastic any reccomendation?
Output driver board, the 100k resistors are ok. I misread them I didn't relized they were not all connected. Three of the 8 in each set are most likely a low side? They are within tolerance. The amp Powers up fine and draws 2.2amps at idle. No output. Missing the 3.3k ohm 1-2watt in the center of the output board. I will check the location and post the identifier later.
R18 is missing from the driverboard. 3.3kohm. I ordered some of the proper wattage. Ill work on the torrids for now.
I will need to look at the schematics to determine what R18 is for, which I don't have on hand.
Have you been able to determine if there is drive to the gates of the output mosfets?
Assuming that all of the operating voltages are present, ie Rails, +/- 12 volts the possible causes are no gate drive to output gates,Preamp board not passing audio, muting circuit failure or the relay or relay turn on circuit has failed. There may be something that doesn't come to mind at the moment.
Have you been able to determine if there is drive to the gates of the output mosfets?
Assuming that all of the operating voltages are present, ie Rails, +/- 12 volts the possible causes are no gate drive to output gates,Preamp board not passing audio, muting circuit failure or the relay or relay turn on circuit has failed. There may be something that doesn't come to mind at the moment.
that resistor missing is a likely cause for the no audio, What ever that resistor is it has alot on it as it gets hot. it burnt up the 1/4 watt resistors i had here for testing pretty fast. I went through and tested all the transistors on the board. I also replaced all the output torrids with new thick shink wrap a clear heavy duty type (Its very durable). I reapplied black silicone and mounting them back. No cracks or dark spots on the torrid. Rebuilt the the ps today. Waiting on matching irf640 to come in i only had irf640N not sure if these amps are ok with them or not. So i went with what is in it.
Just to answer the question about sleeving. I googled the part number for the sleeving we use on our repair warranty amplifiers. I'm not saying you should replace the shrink wrap you have already applied, especially at $260 for a 100ft role!!
Delfingen 3/4" NU-SLEEVE AG-155 C-1 (2500V) Sleeving-Electrowind
R18 is a 3.3KOhm 2 watt resistor, tied to a 1N4742 12v zener diode. This circuit sets up a 12v reference for the over current protection circuit. My guess is you have a problem with the driver board.
Remove the suspected bad driver board and with the opposite side driver board still in place check to see if you have drive to the other side. If so, remove good board and install in place of suspected bad board. If swapping the boards proves good, I can walk you through repairing the bad board. Post pics of the driver boards when you have removed them, so that I can edit and show you possible failed parts.
Remove the suspected bad driver board and with the opposite side driver board still in place check to see if you have drive to the other side. If so, remove good board and install in place of suspected bad board. If swapping the boards proves good, I can walk you through repairing the bad board. Post pics of the driver boards when you have removed them, so that I can edit and show you possible failed parts.
This is the bad driver card someone made a mess of it. I quick chipped it out they made a mess of the via on the board as well.
This amplifier is now flashing in and out of protection as well. I think I may of had a soder bridge between these two contacts for the driver card. I removed it but it was flashing in and out of protection.
Did you post pics of the board, I'm not seeing any?
I'm not clear what quick chipped means? And what via are you referring too?
Yes I did for some reason they are not uploading. I just meant I used quickchip to remove the driver board and repair the damage as I could. From someone reckless attempt at a repair. I will upload the photos again, I hope they upload. I must get the amp out of protection to proceed further.
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