You caught the transients. This amp has three different builds of outputs, all IRF3710. Fro mthe looks of it, some were replaced and some were not. Also, I found a few resistors and a coil de-soldered and barely touching the PCB so I soldered them back in. I think before I go and replace the outputs I'll test this amp again with the loose components re-soldered.
Do I need all 4 transients for testing full power? Each is rated for 1500w if that means anything for this amp.
Do I need all 4 transients for testing full power? Each is rated for 1500w if that means anything for this amp.
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Will IRF3710Z work? Only because Digikey has them.
IRF3710Z Datasheet: http://www.irf.com/product-info/datasheets/data/irf3710zpbf.pdf
IRF3710 Datasheet: http://www.irf.com/product-info/datasheets/data/irf3710pbf.pdf
IRF3710Z Datasheet: http://www.irf.com/product-info/datasheets/data/irf3710zpbf.pdf
IRF3710 Datasheet: http://www.irf.com/product-info/datasheets/data/irf3710pbf.pdf
I removed all 8 IRF3710 outputs to do some points of measurments with the scope referencing amp general ground. There are four 100 ohm resistors connected to Pins 11, 13, 18, and 20 of HIP4080. With the scope set to AC coupling and 2v/Div @ 5us, Pins 13 and 18 are presenting a +-6v square wave. Pins 11 and 20 are showing something either noisy or 'flat lined' on the scope. Is there anything wrong with this? I believe pins 11 and 20 are driving half the outputs. Is the 4080 driver ok?
I have no outputs in circuit at the moment, and also have yet to install the new transients.
I have no outputs in circuit at the moment, and also have yet to install the new transients.
I went ahead and installed two IRF3710Z and all new transients in the amp. The amp powered on with stability so I went ahead and installed all 8 output transistors. With all 8 installed, I could not get the amp to power on because it drags my 10A power supply down and makes some wierd noises. I re-checked all the outputs which all measure up good.
I did not replace the HIP4080A IC, but I did carefully remove it. This IC has probably been replaced once before after I talked with the owner who previously had tried to have it repaired by someone else. With the IC out of circuit, I tried powering the amp which seemed to come on no problem, but I think that caused another problem.
Now, several of the outputs are measureing up shorted across legs more or less. I think running this amp without the HIP4080 installed caused them to fail.
I did not replace the HIP4080A IC, but I did carefully remove it. This IC has probably been replaced once before after I talked with the owner who previously had tried to have it repaired by someone else. With the IC out of circuit, I tried powering the amp which seemed to come on no problem, but I think that caused another problem.
Now, several of the outputs are measureing up shorted across legs more or less. I think running this amp without the HIP4080 installed caused them to fail.
You cannot operate the amp without the 4080 unless it has pulldown resistors. This amp doesn't.
If the 4080 was ever in the amp with defective FETs, it needs to be replaced.
This amp has 4 banks of outputs. Installing 2 wasn't likely to tell you anything significant.
In some class D amps, the deadtime is determined, in part, by the gate capacitance. Having less than the total number of FETs in the circuit can be misleading.
If the 4080 was ever in the amp with defective FETs, it needs to be replaced.
This amp has 4 banks of outputs. Installing 2 wasn't likely to tell you anything significant.
In some class D amps, the deadtime is determined, in part, by the gate capacitance. Having less than the total number of FETs in the circuit can be misleading.
I replaced the bad IRF3710Z and put in a new HIP4080. This amp is having trouble powering up still same as before I blew the first replacement IRFZ3710Zs. The amp seems to power OK for about 2 seconds, but after that it pulls down my 5A and 10A power supplies. Nothing gets hot or shows signs of strain, but the amp does cycle and make some semi-automatic whisstling noise in the power supply area.
During the first 2 seconds of power-up, I was able to measure 10/59/10vDC on the outter four output transistor legs, and 0/10/0vDC on the inner four output transistor legs.
During the first 2 seconds of power-up, I was able to measure 10/59/10vDC on the outter four output transistor legs, and 0/10/0vDC on the inner four output transistor legs.
I was able to set that test scenerio up pretty quickly using a 15A surge protected power supply. The bigger supply made the power supply pulse much faster that the smaller supply. After about 5 seconds two of the 8 output transistors blew without putting up a fight (no smoke) and are now shorted accros all 3 legs. They didnt even get warm. I believe one of the transient diodes may have also shorted.
With the shorte outputs the amp now goes straight into protection.
With the shorte outputs the amp now goes straight into protection.
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I believe the transients were installed correctly.
At this point it is a starting over match. I had only ordered a dozen IRF3710Z and just a few more than enough TVS and HIP4080, all of which are now spent except one spare/good HIP4080. I'm not giving up, just giving the spare-parts bank time to recooperate.
At this point it is a starting over match. I had only ordered a dozen IRF3710Z and just a few more than enough TVS and HIP4080, all of which are now spent except one spare/good HIP4080. I'm not giving up, just giving the spare-parts bank time to recooperate.
I'm back into rebuilding this amp's output section. I'm going to replace all IRF3710Z, the TVS's and the HIP4080.
I have everything but the TVSs in stock. Do I need to order 863-1.5KE18ARL4G from Mouser: Mouser Electronics - Electronic Component Distributor 863-1.5KE18ARL4G
or are these something else?
I have everything but the TVSs in stock. Do I need to order 863-1.5KE18ARL4G from Mouser: Mouser Electronics - Electronic Component Distributor 863-1.5KE18ARL4G
or are these something else?
OK that makes sense. The ones I posted I believe are used in the power supply side and thus I was confused. This is probably why the first rebuild was an utter failure because I used 18v TVSs on the output side.
I'll order up 10 of these Vishay units. 1.5KE82A-E3/54 Vishay Semiconductors TVS Diodes - Transient Voltage Suppressors
I hope I can fix it this time
I'll order up 10 of these Vishay units. 1.5KE82A-E3/54 Vishay Semiconductors TVS Diodes - Transient Voltage Suppressors
I hope I can fix it this time
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