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#301212 - 02/08/2007 21:44 Voltage log
wfaulk
carpal tunnel

Registered: 25/12/2000
Posts: 16706
Loc: Raleigh, NC US
When I start my car, most of the time the empeg boots up and then immediately goes into blinking LED mode. However, sometimes it does not. In addition, when it does go into blinking LED mode, pulling it out and reinserting it lets it boot up and start playing normally, which it does not do if you specifically put it in blinking LED mode.

My theory is that the empeg is not receiving enough voltage at startup, but I don't have any good way to test that. Does the kernel have any way to read the current voltage? Does it have any way to do things periodically? If so, it'd be great if there was some way to keep a log of the voltage, maybe just in memory, that I could look at to at least confirm my suspicions.
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Bitt Faulk

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#301213 - 02/08/2007 22:07 Re: Voltage log [Re: wfaulk]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 31563
Loc: Seattle, WA
Quote:
, sometimes it does not.

Please clarify its behavior in the case when it does not?
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Tony Fabris

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#301214 - 02/08/2007 22:24 Re: Voltage log [Re: tfabris]
wfaulk
carpal tunnel

Registered: 25/12/2000
Posts: 16706
Loc: Raleigh, NC US
It boots up and plays normally. Generally, it works correctly when either I don't turn over the engine or when I do and it's been running within the last few minutes (like maybe after I pump gas). Both of those seem to me to support the idea that it's a voltage issue.
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Bitt Faulk

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#301215 - 03/08/2007 10:36 Re: Voltage log [Re: wfaulk]
tman
carpal tunnel

Registered: 24/12/2001
Posts: 5528
Quote:
My theory is that the empeg is not receiving enough voltage at startup, but I don't have any good way to test that. Does the kernel have any way to read the current voltage? Does it have any way to do things periodically? If so, it'd be great if there was some way to keep a log of the voltage, maybe just in memory, that I could look at to at least confirm my suspicions.

Nope. All the kernel knows is that its either low or okay.

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#301216 - 03/08/2007 12:24 Re: Voltage log [Re: wfaulk]
wfaulk
carpal tunnel

Registered: 25/12/2000
Posts: 16706
Loc: Raleigh, NC US
And to further clarify, when it doesn't work right, It shows the entire boot process, all the way through "loading visuals", then immediately goes into blinking LED mode without ever showing any normal player screen.
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Bitt Faulk

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#301217 - 03/08/2007 12:26 Re: Voltage log [Re: tman]
wfaulk
carpal tunnel

Registered: 25/12/2000
Posts: 16706
Loc: Raleigh, NC US
Well, even that might be enough to at least confirm my suspicion. I think in order to get the information I need, though, I'd have to get the kernel to log it somehow, as I probably need to know this information directly from power-on.
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Bitt Faulk

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#301218 - 03/08/2007 13:24 Re: Voltage log [Re: wfaulk]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 31563
Loc: Seattle, WA
Quote:
It boots up and plays normally.


So I'm confused. The player either boots into sleep mode, or it boots and plays.

I'm not sure which case is the failure case?

It's supposed to boot into whatever mode it was last in. If I sleep the player before I shut off the car and/or pull it from the dash, then it's asleep when I boot it. If it's playing when I shut off the car and/or pull it from the dash, then it's playing when I boot it.

So give me a series of events that you're saying is the failure case?
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Tony Fabris

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#301219 - 03/08/2007 14:11 Re: Voltage log [Re: tfabris]
elperepat
enthusiast

Registered: 11/01/2002
Posts: 211
Loc: Qc, Canada
I, for one, never put the player in sleep mode. However, once every two time I start the car, it boots as wfaulk stated, up to loading visual and then goes into sleep mode (blinking led). I know it's not the intended behaviour, but it did not bother me enough to post it here. But if you're looking for solution, I can reproduce the bug here too.


Edit: I just went in the car and tried to boot it into sleep mode. I tried 5 times without starting the engine, and 5 times when starting up and it booted correctly all the times. I guess that's why I did not bother to post a bug report. BUT, it really does what Bitt mentions, boot into sleep mode when not intended, and boot correctly the time after, sometimes...
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Patrick

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#301220 - 03/08/2007 14:26 Re: Voltage log [Re: elperepat]
JBjorgen
carpal tunnel

Registered: 19/01/2002
Posts: 3582
Loc: Columbus, OH
Mine did that for a while too. New battery fixed it for me, but your milage may vary.
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~ John

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#301221 - 03/08/2007 14:48 Re: Voltage log [Re: elperepat]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 31563
Loc: Seattle, WA
So what you're saying is that the failure case is:

- Player is playing.
- Shut off car ignition.
- Player goes into standby mode because the ignition was shut off.
- Player continues to sit there in standby mode for X number of seconds.
- Player goes into full power off mode.
- Player stays in the dash.
- Turn on car ignition.
- Player boots.
- Player goes into standby mode after booting.

The desired and expected behavior is for the player to begin playing music at that last step instead of going into standby mode.

Yeah, I'd agree something's fishy there. It would be interesting to know if, when the failure case happens, if it's playing the music at the correct spot, or if it rolled back to the prior flash save.

Any chance the players exhibiting this behavior are in need of the diode fix?

Anyone know at exactly which point the player decides what its next bootbehavior is going to be, in the case of that series of events listed at the top of this message? And once it's made that decision, how/when that information is saved?

(The reason I ask is, what happens if it's at the step where it's sitting there for X number of seconds in standby mode after ignition shutoff, and, as Bitt suspects, the voltage drops below its threshold *at that moment*?)
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Tony Fabris

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#301222 - 03/08/2007 15:16 Re: Voltage log [Re: tfabris]
wfaulk
carpal tunnel

Registered: 25/12/2000
Posts: 16706
Loc: Raleigh, NC US
That is an accurate description, but I'll add that you can start the player again after the last step you describe, doing nothing else in between, and it will boot to playing mode. Therefore, the player doesn't think it's in standby mode (thanks - I couldn't think of the correct term) in your last step, as, if it did, it would continue to boot into standby mode.

It continues playing from the correct point; it's not "rolling back". Well, it does every once in a while, but not regularly and certainly not in correspondence with this behavior.

While I do not have a diode in line with the ignition sense, I have none of the other symptoms associated with needing one. That is, I have no amplifier thump, no consistent "rollback", and it goes into standby mode properly when I turn off the ignition.

I'm inclined to say that I need a more powerful battery, but I'd rather get some confirmation that it is a voltage problem before spending $150 on a super-duper starter battery to replace one that's otherwise just fine.
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Bitt Faulk

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#301223 - 03/08/2007 15:21 Re: Voltage log [Re: tfabris]
wfaulk
carpal tunnel

Registered: 25/12/2000
Posts: 16706
Loc: Raleigh, NC US
Quote:
what happens if it's at the step where it's sitting there for X number of seconds in standby mode after ignition shutoff, and, as Bitt suspects, the voltage drops below its threshold *at that moment*?

Actually, I suspect that the voltage drop is at startup. Slowed way down, the sequence of events is:
  1. Key turns ignition sense on
  2. empeg starts booting
  3. key starts starter motor, possibly causing severe voltage drop
  4. empeg finishes booting
  5. empeg goes into standby mode

My suspicion is that the empeg makes a voltage determination somewhere during boot, at the end of the boot, or just before it starts playing as to whether or not there's enough voltage to play properly, and it sees that the voltage is low enough that it should not, and goes into pseudo-standby mode.
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Bitt Faulk

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#301224 - 03/08/2007 15:51 Re: Voltage log [Re: wfaulk]
elperepat
enthusiast

Registered: 11/01/2002
Posts: 211
Loc: Qc, Canada
Same here: It's always at the correct spot when starting (no rolling back). As Bitt says, if I stop the car and restart it, it will start correctly, disregarding the fact that it was in "incorrect sleep mode" the last time it stopped.

Concerning the diode, I have a M2a, so I shouldn't need the diode.
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Patrick

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#301225 - 03/08/2007 16:25 Re: Voltage log [Re: wfaulk]
wfaulk
carpal tunnel

Registered: 25/12/2000
Posts: 16706
Loc: Raleigh, NC US
Actually, I realized that we had a min/max multimeter here at work. I hooked it up to the power connectors in the sled in my car. It read about 12V. I turned the min function on and started the car. It got down to 7.76V. I would be very surprised if that was not the problem.
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Bitt Faulk

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#301226 - 03/08/2007 16:49 Re: Voltage log [Re: wfaulk]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 31563
Loc: Seattle, WA
Yeah, but all cars dip in voltage when you start the motor. Mine does, too. The empeg is supposed to handle that correctly.
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Tony Fabris

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#301227 - 03/08/2007 17:37 Re: Voltage log [Re: tfabris]
wfaulk
carpal tunnel

Registered: 25/12/2000
Posts: 16706
Loc: Raleigh, NC US
I measured some more things. My battery is in my trunk. Measuring across the battery, the voltage dips to about 10.1V. Measuring between the fuse block and the chassis under the hood, it dips to 7.72V. So it would appear that there is something wrong with the wiring somewhere between the trunk and the engine compartment. Then again, that's a long cable and a lot of current. Maybe a 2.5V drop across that much cabling is "normal".
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Bitt Faulk

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#301228 - 06/08/2007 20:43 Re: Voltage log [Re: wfaulk]
Major_Sarcasm
member

Registered: 28/08/2003
Posts: 149
Loc: Isle of Wight, UK
Interesting thread.

I've had my player exibiting this behaviour since fitting it to my most recent vehicle (an aging Nissan Skyline). These voltage drops could be the cause of my symptoms too. My Empeg wasn't doing this in the last car I had though (incidentally also an aging Nissan, but a Pulsar instead). Fitting the player to the GTR also coincided with an upgrade to V3A11, so I'm wondering if this could have anything to do with it too.

I might borrow a battery and see if it cures/alters the behaviour at all.
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Steve

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