So, it looks like you did everything correctly... I would have assumed that, but it does seem to be the case that sometimes you can't assume that sort of thing. So, I wanted to be certain.
The device you have is the flash-memory based device, as I assumed was the case. Good to know.
I have one more suggestion to try... IF YOU ARE ABLE. Do you have any of the various "dock" devices which are (or rather, "were?") available for the Archos Gen 5 and 6 devices?
The various options are, as far as I'm aware, the following:
1) The Archos Mini Dock.
2) The Archos Battery Dock.
3) The Archos HDMI Dock.
4) The Archos DVR Station.
If you don't have one, do you know anyone who might have one? I realize, the answer is likely "no" to any of those, but I wanted to ask.
The reason I ask is that each of those has a means of a secondary audio output, unrelated to either the speaker in the device, or to the headphone jack in the device. The first two have an "octopus cable" which provides a composite video, S-video, and right and left audio channels. The third can output digital audio via HDMI. And the fourth can output audio either by left/right RCA jacks, by HDMI, or by SPDIF digital (through an RCA jack, not through optical), and video by component, composite, S-video, or HDMI.
I woudl not expect you to have one, but if you have one, or can find one in the possession of a friend, it would be very helpful as part of the diagnosis.
Again, I hate to seem insulting... I'm sure you've checked this... but are you certain that the volume is not just turned down, or muted? (I'm 99.9% sure that it's not going to be the case, but I've known people who worried over a device for a week, until discovering that they'd forgotten to plug in the power cord, for example!)
There are very limited sound settings in the Archos 5IT, as I know you've discovered. Basically, you have an audio volume setting, an option to choose whether or not you get a 'click" when hitting the screen (I like it, but I know people who don't), and an option to set up the "equalizer" (which doesn't work when using the built-in speaker, of course).
The volume control for this, obviously you've figured out. But the fact that you have to hold it as long as you do is VERY interesting... it infers that this control could be malfunctioning in some way. I strongly recommend you confirm whether or not this might be a mechanical problem related to this control.
So, the one question I asked, and which you didn't explicitly answer... are you sure that the volume is turned up and is STAYING UP? That is... if you go into a song, through the Archos Media application, and start playing... then click the screen, you should see the volume meter/adjustment slider on the right edge of the screen. You can drag this up and down, or you can press the "buttons" above or below the vertical bar, and you can adjust the volume that way.
I ask that because this is EXACTLY what I saw when my "down volume" button was being pressed by the wire caught between the plastic button and the circuit-board-mounted actual control. I mean... the thing would "beep" during startup-shutdown events (which are not subject to the software volume control) but I was dead silent for everything else. Of course, that was on my A5IMT, not the A5IT... (I have both)... so I'm not sure if that would happen with the unit you have.
The weird thing is that you DO hear a "storage disconnect beep." That tells me that the speaker must actually be OK.
I think you said you'd tried all of the "Repair and formatting tools." Is that true? That is... everything from "Clear temporary files and system cache" down to "full reinitialization," in sequence?
A "full reinitialization" will reset everything in the OS to "factory standard" default settings, and should eliminate any software "misconfigurations" which might have been retained after re-installing the OS (I DO think that the OS settings are retained when the OS is updated or reinstalled).
If you do that, after having already done a full flash-drive reformat (as you've clearly already done)... ig you're certain that the volume control is set to an appropriate level and is staying there, not dropping due to a switch problem... and the problem persists, it's almost certainly a hardware problem with the headphone jack. That's actually something you can find discussed in another thread on here: http://forum.archosfans.com/viewtopic.php?f=47&t=65270
A broken headphone jack might FOOL the unit into thinking that a headphone is inserted, even when one isn't... but would not permit sound to leave through the jack (again, due to the jack being broken). But you WOULD get the "shutdown beep."
This could be anything from a bit of conductive material being jammed into the headphone jack (a relatively simple fix, albeit one which requires some fineness to fix), to a jack which is broken away from the PC board (also relatively simple to fix, but requiring a bit more prep-work to manage)... to an actual BROKEN connector (ie, conductive elements inside the connector having been bent, broken, or deformed in some fashion).
If you can get access to a dock of some sort, test to see if the audio output through that works. If it does... you'll know you have a hardware problem, and almost certainly it's the headphone jack. If it doesn't... and if you've checked to ensure that your "volume" setting is not dropping down to the bottom of the setting range... then it's very, very likely that you have a problem with your headphone jack having junk in it, being broken away from the circuit board, or being broken internally.
If it's a software thing, the "full reinitialization" along with the drive reformat should clear it up. If it's not, it's certainly a hardware thing. If the volume won't stay up, it's related to the volume switch. If it's constant, and you get the "shutdown unmounting beep" but nothing else.. it's the headphone jack, no question.
Archos can repair things like this, but they'll charge a HUGE amount to do the repair. When my hard drive on my A5IMT started to fail, the told me that they could replace it... but the cost was more than the original cost of the device! I found a guy on Ebay who was able to help me out (he also, as I've learned, posts here... which is how I found this site!) . This cost me less than 1/3 of what Archos wanted to charge me for the same service. (Archos doesn't want you to keep your current equipment, they want to sell you NEW equipment, after all.)
You might be better off finding a local shop... or even, as I've done, repairing it yourself (if you feel competent to do so).
There are guides to disassembly of an Archos player... you can find some info here, and also on another site here: http://archos.g3nius.org
There may be others as well. Also, you'll want to search "Youtube" for some useful videos.
I'd take that approach, personally, but I have the right tools and skills. If you don't... or just don't have the inclination to try... you can take it to a local electronics repair shop, point out what I've just told you, and tell them what I've told you as well. Instead of the couple of hundred I suspect Archos would charge you, they can likely fix a headphone jack issue for less than $50 US (maybe a LOT less). The hardest bit is getting the case apart, honestly.
My unit is a hard drive unit, so I can't give you direct guidance on repair of a flash drive unit. Though, I'm sure that the internals (especially the circuit board) are likely identical in virtually every major way.
In the end, if none of the above work... and if you can't find a local electronics repair shop you trust... you'll want to try these guys.
http://archosrepairs.com/repair-archos/ ... /1509.html
While I have not personally done business with them, they seem knowledgeable and I have not heard anything negative about them. And they're quite a bit less pricey than sending something back to Archos is going to be.
I hope this helps.