Ok, I've now tried it a few times on my player. If I pull power whilst the disks are spun up then I don't see the "The quick brown fox" message. I have two disks and 64MB of memory so it takes a while to fill the cache after boot, and the drives can sap power, so this isn't completely unexpected. If I wait for the disks to spin down and then pull power I usually see some of the message. I don't have those two final "Powerfail is now..." messages that you don't. but if I understand you correctly then your player is in Standby after boot (which you can't change until we resolve this flash save issue), and these messages occur when you come out of Standby. The kernel code supports this behaviour.

So, you need to repeat the experiment a couple of times ensuring that the disk is spun down before pulling power. If the results don't change then don't bother posting a complete log, just let us know.

Assuming that they don't change then it is probable that the message is not getting sent. There are two possibilities that I see for this. First is that the kernel is attempting to write the flash but never gets done, and second is that the kernel isn't even trying (not seeing power fail).

Where from here? You could look at the GPIO pins on the CPU I suppose. GP0 (pin 86) is the POWERFAIL input. It's monitored for transitions not levels. I dare say that a proficient electronic tech could find a way to safely manipulate that pin so we could see if the kernel picks it up.
You could also scope the FLASHWE pin (output, Flash write enable). That's GP20, pin 60.

Alright, I tried again making sure the drive was spun down, no luck. My empeg is bone stock with a single 12G drive. I will unfortunately be busy for most of the weekend but I will check the powerfail line as soon as possible. Thanks for the technical info on the CPU lines (don't suppose part of a schematic would be available?) I will post as soon as I have been able to try what you've suggested.

Thanks again
Nick

No, the schematics are not publically available. Rob Schofiel has them though, so may be able to help you trace a signal.

Ok, now we are getting somewhere. I am not getting any voltage on pin 86 when the empeg is on. I traced the signal back by the power supply and am kind of stuck now. While the empeg was running I injected 3.3V through a 10K resistor and the empeg quickly saved to flash and blanked the display for a 1/2 second and then kept running kind of like a quick reset. Now when I reset power it comes up to that very position that I manually saved. I have repeated this process 3 times so I think everything will be fine if I can figure out how that signal works. I have attached a pic that shows the part of the power supply in question. I have traced the powerfail signal back to a 8 pin part marked 8532A that appears to be some sort of switch or something. I need help in figuring out what this is and how the powerfail part of the circuit works. Hopefully someone will be able to shed some light on this and I can get this up and running again.

All I want for x-mas is for my empeg to work.....

Thanks in advance for the great help.

Nick

I can't help any further than that - I don't know what that chip is. I'm guessing that it is a power supervisory circuit, but I can't find any datasheet that matches the number. Rob?

It's a dual op-amp package by Analog Devices, (AD8532), using one amp as a unity gain comparator in a fast power fail detect circuit. It drives through a 1k2 resistor to GP0 on the processor.

Probe pin 2 = DC input voltage (nominal car battery voltage, ie. "12v")
pin 3 = 3V power line for processor/RAM/FLASH.

Output is on pin 1.

Interesting. I swear I replied to genixia, but my post has gone missing.

Problem Solved!!! Thanks to everyones help I was able to find a broken resistor on the 3.3V divider input to the op-amp. This did not measure correctly but looked fine until I put it under a microscope. I was able to attach a fairly high resolution pic that shows the resistor in question. It looks like the solder end broke loose from the ceramic plate on the left side of the resistor. I suppose this was slightly weak from the start and just failed due to thermal stress over the past year or two. I appears that the powerfail line sits at 0V under normal operation, then when power is removed the comparator flips and puts 3.3V on the line until it dies. I will fully assemble it tonight and try it out, (can't wait!)

I really appreciate everyone who helped me on this, I would not have been able to find it with out you all. Special thanks to Genixia and Rob.

It looks like I get my X-mas wish after all.

Nick

Just doin' mah job, ma'am!

Glad I could help a little - you carried out the hard work, and had the inspiration while I was still scratching my head. Pat on the back to you for helping resolve the first recorded Power fail circuit failure diagnosis!

Great news, I'm glad that you got it resolved.

That photo is a corker. Was that taken through a microscope? The fault itself is rather unusual. Resistors are generally incredibly reliable (assuming they're sized correctly for their expected dissipation of course). I think that you could be winning the Most Obscure Failure award at the moment.

Welcome to my life... I seem to be able to fix almost anything for anyone else but when my stuff breaks it is usually the most bizarre types of failures imaginable. Murphy's law I guess.

I took that pic through a handheld 10X magnifying eyepiece, worked pretty good. I have a 90X scope at work that really shows detail but no camera adapter.
Anyway, on behalf of my Empeg and myself, thanks again.

Nick

It would not surprise me if one day someone on this board had the means and the motive to post a Scanning Electron Microscope picture of their empeg board. We've already seen an infrared heat signature picture, then there's that picture, it's the next logical step.