The amplifier is able to produce a rail voltage of +-29.5vDC, and the opAmps are getting +-14.9vDC at the power pins.
When nothing is connected to the speaker terminal outputs or RCA inputs, the speaker terminal outputs present a 0.8vAC clean sine waveform. There is also 0.8vAC from RCA shields to amp general ground. Powered off, meter reads OL resistance on RCA sheilds referencing amp ground. in fact, the meter reads OL on RCA shields referencing almost anything inside the amplifier.
As soon as I connect my frequency generator to RCA inputs the amplifier goes straight to 29vAC across the speaker terminals, and on the scope I see a waveform like I've not seen before.
10 Volts/Div and ~2mS
When nothing is connected to the speaker terminal outputs or RCA inputs, the speaker terminal outputs present a 0.8vAC clean sine waveform. There is also 0.8vAC from RCA shields to amp general ground. Powered off, meter reads OL resistance on RCA sheilds referencing amp ground. in fact, the meter reads OL on RCA shields referencing almost anything inside the amplifier.
As soon as I connect my frequency generator to RCA inputs the amplifier goes straight to 29vAC across the speaker terminals, and on the scope I see a waveform like I've not seen before.
10 Volts/Div and ~2mS
What is the resistance from the B+ terminal to the RCA shield?
You have to use a nylon screw in the location shown in the photo above. If you don't, you'll get a ground loop if the amp is mounted to the vehicle's chassis. I find it best if you use a nylon screw that will have about 1/2" of threads above the board when the screw is screwed down to the bottom of the mounting hole. Then use a nut and an insulating washer (if you're using a steel nut) to tighten the board down. You'll need to make sure that the plastic cylinders are under the board (assuming this is like the ZR series amps) so that the board doesn't contact the metal mounting boss. If there is no cylinder or insulator, insert insulating washers between the boss and the board. There is a note about this in the ZR600 folder.
You have to use a nylon screw in the location shown in the photo above. If you don't, you'll get a ground loop if the amp is mounted to the vehicle's chassis. I find it best if you use a nylon screw that will have about 1/2" of threads above the board when the screw is screwed down to the bottom of the mounting hole. Then use a nut and an insulating washer (if you're using a steel nut) to tighten the board down. You'll need to make sure that the plastic cylinders are under the board (assuming this is like the ZR series amps) so that the board doesn't contact the metal mounting boss. If there is no cylinder or insulator, insert insulating washers between the boss and the board. There is a note about this in the ZR600 folder.
Hmm This sounds like Kicker may have a design flaw because the screw pictured is the one which came out of there. Seems Kicker amps of this series have several problems or easily malfunction grounding and shielding issues.
This amp is a very large kicker and has a lot of support... I'm tempted to just leave the screw out as there are a few others holding the board down. I'll have to check how stable this is, or just go and get a nylon screw. BTW this amp has the largest transformer coil I've ever seen in any amplifier (Except the JBL GT600 Crown amp).
I'll check shield to B+ resistence tonight.
Thanks!
I see resistence from RCA Shield to B+ at 34 ohms. Powered and referencing amp general ground, RCA shields are measuring 13.8vDC.
This amp also appears to be having some kind of grounding crisis... Sometimes the amp will power up fine when other times it will just throw my ps into protection. If I have the screw installed pictured above, the amp always throws the supply into protection.
Theres definately some variation the transformer. After playing with it for a few minutes, I now have 20 ohms across those two points. Twisting or pressing the transformer only seems to reduce ohms of resistance temporarilly. If I power cycle on-off, the resistance goes back up to 35 ohms.
At no point was I able to get anything higher than about 35 ohms.
At no point was I able to get anything higher than about 35 ohms.
Theres an insulator underneith the PCB keeping the PCB completely clear from shorting to the heatsink. I'll have to run and get a nylon screw to make that point strong to the heatsink. The amp is back together now and appears to be 100% working atm.
I still cant really understand why Kicker did that...
I still cant really understand why Kicker did that...
It was definately metal flake wedged in the insulator. It pierced right through and when pressed hard to the heatsink was causing a short. The flakes were so heavy it almost looked like a manufactoring issue Supposedly this is one of Kicker's best/big amps and last series from the late 90s... Must have been a disgruntled factory worker. I bet when I lifted the PCB the first time the flake moved about and the second pressing created the short.
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