Post #9:
Some of the 4x21844S boards had 270 ohm and some had 330 ohm in the location of R30. The photo I looked at had the 270.
I wasn't aware that there was a driver board with 4 2184S ICs.
The schematic diagram shows a circuit that's not going to be reliable. It relies too much on the gain of Q13 (which will vary with temperature). R80 isn't going to act as a reliable voltage divider component because it's in series with a capacitor. A change in frequency would change its effect on the circuit.
Have you tried paralleling a short piece of small (16g) wire across the shunt resistors to see if that would stop it from shutting down (and confirm that the problem was indeed in the over-current circuit)?
Does the M4 amp use the same driver board for the audio?
Some of the 4x21844S boards had 270 ohm and some had 330 ohm in the location of R30. The photo I looked at had the 270.
I wasn't aware that there was a driver board with 4 2184S ICs.
The schematic diagram shows a circuit that's not going to be reliable. It relies too much on the gain of Q13 (which will vary with temperature). R80 isn't going to act as a reliable voltage divider component because it's in series with a capacitor. A change in frequency would change its effect on the circuit.
Have you tried paralleling a short piece of small (16g) wire across the shunt resistors to see if that would stop it from shutting down (and confirm that the problem was indeed in the over-current circuit)?
Does the M4 amp use the same driver board for the audio?
I assume that because the LED goes off completely, that the SG3525 is actually shutting down, not the protection circuit...
I'll try to pull the amp apart today, with it still wired up in the car, and get some voltage measurements off the IC...
Its too difficult to remove the amp, I probably should have tried to trouble shoot it before I installed it, but wasn't entirely sure that the issue would occur...
Older pic, can't really see the amps, but you get the idea.
Fortunately its the front amp, so I can just undo the mounting screws and flip it forward, which I've done before as one amp reached clipping WAY before the other when I first installed them...
Going to use this thread as reference:
http://www.diyaudio.com/forums/car-audio/174907-digital-designs-z1.html
Maybe I've broken a component led too, which only goes open circuit when it warms up... and maybe it gets warmer with the higher input voltage
maybe...
I'll try to pull the amp apart today, with it still wired up in the car, and get some voltage measurements off the IC...
Its too difficult to remove the amp, I probably should have tried to trouble shoot it before I installed it, but wasn't entirely sure that the issue would occur...
Older pic, can't really see the amps, but you get the idea.
Fortunately its the front amp, so I can just undo the mounting screws and flip it forward, which I've done before as one amp reached clipping WAY before the other when I first installed them...
Going to use this thread as reference:
http://www.diyaudio.com/forums/car-audio/174907-digital-designs-z1.html
Maybe I've broken a component led too, which only goes open circuit when it warms up... and maybe it gets warmer with the higher input voltage
maybe...
I don't know if the diagram I have is the same as your amp but on this version of the Z1, R229 and C299 are connected between the two grounds.
With the RCAs plugged in, you'd read less than the 1k ohms of R229.
The attached image is the plate from the service manual. Is it the same as the one you have?
With the RCAs plugged in, you'd read less than the 1k ohms of R229.
The attached image is the plate from the service manual. Is it the same as the one you have?
Attachments
R229 and C299 is correct, yes
But the headunit rca ground measures open circuit to chassis ground, as the pico fuse has blown.... and it seems the amplifier really expects this to be tied to ground, otherwise, as you've pointed out, its basically floating (with a 1k resistor tying it to ground)
But the headunit rca ground measures open circuit to chassis ground, as the pico fuse has blown.... and it seems the amplifier really expects this to be tied to ground, otherwise, as you've pointed out, its basically floating (with a 1k resistor tying it to ground)
I dont know whats going on...
rca metered fine, so then I measured the rca headunit power (ground connection) plug, to ground... about 10 ohms.... well that isn't right...
measured from battery negative to headunit ground, 130ohms? I assume its not really 130ohm, but that voltage drop along the cable causes the odd reading?
rca metered fine, so then I measured the rca headunit power (ground connection) plug, to ground... about 10 ohms.... well that isn't right...
measured from battery negative to headunit ground, 130ohms? I assume its not really 130ohm, but that voltage drop along the cable causes the odd reading?
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there's voltage drop between the headunit ground, and the battery ground.... and if you turn the headlight on, the drop increases (about 50mv max)
the reason I measured ~50ohm to ground at the amplifier, and assumed the picofuse was blown, was because the voltage drop resulted in weird resistance readings...
the reason I measured ~50ohm to ground at the amplifier, and assumed the picofuse was blown, was because the voltage drop resulted in weird resistance readings...
new ground to the headunit (there was a 4ga cable running behind the centre console to the front stage amp under the front seat) so I just spliced a 12ga cable into that...
Now the rca ground measures 0 ohm to the battery ground....
I'm pretty sure this was the issue....
ever so slightly intermittent ground on the headunit, resulting in a 50mv difference between the rca ground and the battery ground...
Now the rca ground measures 0 ohm to the battery ground....
I'm pretty sure this was the issue....
ever so slightly intermittent ground on the headunit, resulting in a 50mv difference between the rca ground and the battery ground...
Amp shut down once yesterday on a 10 minute drive... if only they had multiple LEDs for each protection circuit!
I played music flat out while driving for about 30 seconds to a minute, no worries, turned the volume down, bass kept going, track ended, next track started... no bass.. few seconds later I heard the click of the relays coming in, and had bass again....
hmmm...
I played music flat out while driving for about 30 seconds to a minute, no worries, turned the volume down, bass kept going, track ended, next track started... no bass.. few seconds later I heard the click of the relays coming in, and had bass again....
hmmm...
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