Any tips from those who have done any work on these amps would be appreciated. Mine is a Mar 2003 vintage amp that was sent to me by Guitammer when the first amp I had died. This one is clearly out of warranty so it is either fix it or buy a new Amp.
Next week we will be doing the Smoke Test on the Amp as I put it back together to see if we have fixed all of the problems or if there are possibly dead Semiconductor components.
Comments are still welcome.
After replacing the numerous bulging and blown electrolytics I found that one of the Bridge rectifiers had also departed life. I replaced that and all the supply voltages are now normal. I started tracing the Class D circuit and the small audio preamp board with the volume and frequency cutoff controls is working fine. The audio signal was arriving fine at the TL074CN op amp on the power Amp board, as was the sawtooth signal on its other input. However there was no output from that Op Amp that is essentially the Integrator that creates the Class D signal. I replaced that OP Amp this week which turned out to be a bit difficult to remove because of the very small plated through holes. Even with a commercial vacuum assist solder sucker I could not get the pins to release and had to use a dremel tool to cutoff each of the IC pins at the body of the IC and then heat and pull them one by one from the board. I then had to drill the remaining solder out the holes with a number 65 drill. (Not sure why they use such fine plated through holes on a 14 pin DIP IC). So once the TL074CN was replaced, that whole portion of the circuit is now working. I get a square wave from the TL074CN going into the IR2111 FET Drivers that varies in pulse width as the input audio frequency is changed. It now looks like the two IR2111 FET drivers could be bad so once again I need to remove the board, pull those two ICs and replace them. I should be able to get to that next week.
You don't want to try and remove all the solder and then try to get the component out. Take a good hot soldering iron and put on a TON of solder down one side of the chip and roll is back and forth with the soldering iron while prying up on your component, then repeat for the other side. I usually don't do any desoldering until the old components are out and you're just clearing the holes.
I do the same thing with capacitors and stuff too, if you can get both pins hot at once, it will pull right out. Just hold your iron at an angle and put the solder on liberally...most of it will pull out with the component that you're removing.
Sorry if I'm no help at all, just figured I would try and contribute
The last items were two 15 volt Zeners that were bad. After getting the circuit to work all the way up to the input of the IR2111 Gate Drivers that drive the 30 amp MOSFETs in the output, I found that the bias voltage on the IR2111s was only 7 volts instead of 15 volts. So replacing the two 15 volt zeners in the power supply fixed that and the amp started working again. I had missed these in doing the initial power supply repair as I didn't realize that this single 15 volt supply was referenced off of the negative rail of -80 volts. In the end I had to replace about a dozen electrolytics that were bulging or blown, one Bridge rectifier, Three 15 volt Zeners and one quad Op Amp. I learned a lot over the last couple months as I was not familiar with Class D amplifiers going into this repair and only could work on this part time. If anyone reading this has questions about repairing their BK1000 amp, I would be happy to share what I can.
Looks like I can get all my Buttkickers working in the theater again this weekend.
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Hello....newbie here. My BKA 1000 has recently bought the farm as well. I know nothing about electronics but I do know what a bubbled cap looks like and I do have about 6 or 8 of them including one where the shell on the cap blew right off the base....and maybe much more wrong with it...I just don't know. It just wont come on and the red standy light is off. My dad is a retired TV repair man with extensive experience with schematics. Doyles, would you be willing to share your schematics sheets? If I can't fix this, I'm looking at a new one and not sure the wife will be too happy about that.