Doesn't hold standby power if I crank the car right away

I know I have bagged the M4, mainly because of the RF noise it produces (which I have fixed), however the components used and the latest PCB quality are really good. I would be surprised if another supply is going to produce more stable rail voltages, they look rock solid on my test gear.

The timing I was referring to is only accessible from a separate program that’s available for the M4, Lots of warnings before it runs but it allows start-up sequence timing for individual ATX voltage rails to be controlled.

I don’t think rail voltage stability is the problem in this case. It’s more to do with what a PSU does when it sees a certain condition on the input supply. I could not be sure whether the MB was seeing a problem and tripping the power good line and making the PSU drop +5v Standby or weather the PSU was momentarily (like a few ms) rechecking/adjusting to the incoming +12v variation and thereby causing the MB to pull the power good line because of this slight delay.

One thing I never had time to try was powering +5 standby separately. Now I don’t know if the MB will invalidate RAM contents when it signals a Power good fail. If it doesn’t, the MB may well resume from STR if the ram contents have not been lost?

If the program your talking about is a seperate program that uses the USB interface to change timings then i think we are talking about the same thing. There is drop down menu with all the various settings you can adjust and a send button to apply (you actually have to remove power from the M4-ATX before the new setting take place).

Thats good news about the quality of the M4 and stability of the rails.

One question...
Did you ever experience wavy interference lines in your display because of the M4-ATX? or was it just RF interferance in your radio and audio?

While bringing the carpc in the house and hooking it up to a different monitor i noticed the wavey interferance lines were still present meaning it must be coming from the M4-ATX.

Quote:

---

Originally Posted by Mickz

One thing I never had time to try was powering +5 standby separately. Now I don’t know if the MB will invalidate RAM contents when it signals a Power good fail. If it doesn’t, the MB may well resume from STR if the ram contents have not been lost?

---

How would you wire this up? get a seperate 5v regulator and attach it directly to the 5vsb pins on the mother board disconnecting the ones from the m4?

Also one other thing i was thinking of is that maybe adding a couple more second delay before it actualy starts up for things to normalize. i will test that when i get the motherboard back.

I have an isolator in place so maybe there is a spike when the Aux battery gets connected to the running alternator that is causing the problems. The voltage would jump from ~11.8v to 13.7v. If this happening right as the M4-ATX is powering on perhaps that is causeing the symptoms?

Quote:

---

Originally Posted by antimatter

If the program your talking about is a seperate program that uses the USB interface to change timings then i think we are talking about the same thing. There is drop down menu with all the various settings you can adjust and a send button to apply.

---

There are two control programs, not including the tray monitor. Both have a drop down menu to send and read command and status.

I think the bigger one with a lot more info and options is called the OEM setup. I don’t have it installed on this PC so can’t look it up at the moment.

As far as interference to the screen goes, the M4 should not really impact on that, however with the quality and unshielded layouts on some LCD displays nothing would surprise me.

In all noise testing I carried out with the M4 I never once encountered a problem with video. I run a 5M VGA cable from the rear of the car to the Display, no interference on the coax reversing camera run either, if the M4 was causing a problem this is where I would expect it to show up. My Monitor is powered from 3 sources, +12v output from the M4, +12v reversing light supply and program controlled switched +12v for recording while driving.

Like most Switch mode supplies the M4 generates quite a bit of noise, however it’s more the spectrum or bandwidth that the noise from the M4 covers. Starting from Audio through VHF and extending above UHF and Sat Nav frequencies – that’s the problem in the M4.

Quote:

---

Originally Posted by antimatter

How would you wire this up? get a seperate 5v regulator and attach it directly to the 5vsb pins on the mother board disconnecting the ones from the m4?

---

You would need some simple logic to control a separate +5v standby supply.

Basically for a test you want a separate +5v supply to be controlled by the M4 +5v standby.
When the M4 bring up its +5v standby it turns on the separate +5v supply, but you want a delay of a few seconds before the separate +5v drops after the M4 removes standby voltage. That should tell you if holding standby will solve the problem, or cause more?

Quote:

---

Originally Posted by Mickz

There are two control programs, not including the tray monitor. Both have a drop down menu to send and read command and status.

I think the bigger one with a lot more info and options is called the OEM setup. I don’t have it installed on this PC so can’t look it up at the moment.

---

I just use the regular one. I don't think i want to go down that road either

Quote:

---

Originally Posted by Mickz

As far as interference to the screen goes, the M4 should not really impact on that, however with the quality and unshielded layouts on some LCD displays nothing would surprise me.

In all noise testing I carried out with the M4 I never once encountered a problem with video. I run a 5M VGA cable from the rear of the car to the Display, no interference on the coax reversing camera run either, if the M4 was causing a problem this is where I would expect it to show up. My Monitor is powered from 3 sources, +12v output from the M4, +12v reversing light supply and program controlled switched +12v for recording while driving.

Like most Switch mode supplies the M4 generates quite a bit of noise, however it’s more the spectrum or bandwidth that the noise from the M4 covers. Starting from Audio through VHF and extending above UHF and Sat Nav frequencies – that’s the problem in the M4.

---

How do you have the M4 grounded? More exactly do you have your M4 grounded to your computer case.

So I got my motherboard back. I put everything back together and low and behold all the wavey interference lines in my LCD are gone! I am stoked about that.

The bad news is as we all suspected I still have the issue coming out of standby where it cycles power on/ off every 5 seconds. I was getting it to fail almost everytime. I changed the startup delay to 5 seconds and it hasn't failed since (10 sleep/wake cycles). What is notable is that this was all outside of the cars electrical environment. I did this all on my workbench.

I will continue to monitor and test once I get this back in my car

So i have everything hooked up back in the car. From my testing it appears it is no better than before.

My orginal problem (title of this thread [not holding standby power through crank]) was solved by moving to the IGN wire instead of ACC. The Diode and Capacitor are also in play and I havent lost standby power through the crank in quite some time. However i do have the issue where the motherboard recognized bad power and goes in a startup loop.

Oh and with everything hooked up in the car there are just a little bit of wavey interferance lines (not as bad as before) but it is still somewhat present.

So moving foward i am unclear on how to proceed. It appears i just have plain old compatibilty problem which could only be resolved by changing hardware platforms, agree?

Two things... I thought I would post an update and also ask MickZ a question. In your testing did you ever play with the ACPI settings of your motherboard BIOS?

My motherboard has options for ACPI v1.0, 2.0 and 3.0. By default it was set to v3.0 (having power on cycle issues). I changed it v2.0 and it seems to like it better.

Since I last posted I haven't experienced the issue after I changed that setting in the BIOS... could it really have been as simple as that?

Anyhow I will be going back to work on Monday so I will be using my vehicle more and time will tell if the issue persists.

Thanks to all who participated in helping me find some answers

I have been testing this and trying to get it to fail and I can't I probably went through 20 sleep cycles this evening on top of maybe another 5 throughout the day today and I never lost standby through the crank, and I never had the power on/off cycle issue.

I did however on one or two occasions notice that I never actually achieved sleep. Let me explain. The computer would receive the sleep command and it would start to sleep (then it would start writing the mem file to disk for hybrid sleep) and before it was done writing the file it would kick back on. I am not too concerned with this since it is either a random USB device keeping things from sleeping or its a setting on the power off retries on my M4. Either way its no big deal cause it will just kill the power after 90 seconds if it isn't shut off by then.