As I've said, there's nothing we can do with the hardware. This is an EOL product. There are no newer front board designs, nor will there be.

We either try to fix it in software - and I believe it *can* be fixed in software, or you do without your player. Whilst I'd like to try and do a thorough fix, like possibly change the PIC code on the display board or the oscillator, it ain't going to happen as it's not cost effective.

The brightness changing when at 100% is an indication of a problem with the comms between the main board and the button PIC - the button PIC is getting 100% commands from the main board but misinterpreting the byte and as such is setting the dimmer level to different values every time a byte is sent from the main board.

The fact that, for some people, temperature appears to have an effect, is not an indication of a dodgy component as far as I can see - and I designed the circuitry. I believe it's an indication of a problem with the main board -> display board comms protocol or loading of the display board PIC.

Hugo

Have you tried adjusting the brightness with the remote?

This is the only way that you can be sure that the button PIC is not busy. Using the buttons *or* rotary control will mean the PIC is busy with sending a fake-IR sequence to the main board whilst the main board is trying to send a new dimmer setting to the display.

Hugo

We don't have facilities to cool chips, etc (not even any freezer spray!) but as none of the components run hot, that isn't an issue.

As I keep saying, I believe it's the oscillator on the button PIC and the issue is simply down to comms timing.

You cannot verify it using any of the front panel controls, as all of these will interfere with correct reception of dimmer commands by the front board. Yes, this is a design flaw, but the dimmer was added very late in the design cycle using spare pins on the PIC, hence the nasty interactions between non-IR input and front board commands.

Hugo

Dimming is done by adjusting the HT supply to the VFD. This isn't the *best* way of doing dimming - the best way is to increase the blanking intervals, but this isn't possible with the LCD interface on the CPU (at least, not to the same extent). As the display gets dimmer and dimmer, there may well be non-linearities in the screen brightness.

Hugo

Yes, I've tried to change the brightness with the remote,
and No, it *didn't* fix the bug. If I set it to 100% and then, *using the remote* tried to go "beyond" 100% the brightness still varied randomly.

Let's step back and take stock of this. I think we are losing track of the situation.

There would seem to be FOUR unrelated dimmer related issues.

1. Player sometimes boots up in dim mode, until the player starts. Yes - it does - we can't do anything about it.

2. Screen flickers on/off bright/dim all over the place at random, or goes permanantly ultra dim (barely viewable on 100% brightness). This is a component (capacitor?) fault on the display board. It can be fixed under warranty, and I seem to recall that we've only seen two or three cases in total. So - support issue, don't ask for a fix here, contact [email protected].

3. Screen occassionally switches into dim mode, and then back to bright mode. This is believed to be a player software bug (of sorts). A single glitch on the dimmer input is interpreted as a PCM cycle causing the display to dim. A second or two later the player notices the lack of further PCM cycles, and un-dims. Solution - more thorough PCM detection in the player software. We'll look at this for a later release.

4. Screen brightness is erratic when adjusting the dimmer using the front panel controls. Sometimes (rarely) the incorrect brightness level is set by the auto dimmer. This is a shortcoming of the display board processor. This chip is not software upgradable. It is possible that this could be affected by manufacturing variance or temperature, as the PIC runs from a very simple oscillator - but the problem is within the protocol (which should not be so sensitive to small variations). We can't think of any way to fix this in the player software, and neither is there a hardware solution. The dimmer should mostly work fine, except when setting the level from the front panel. If you're not satisfied with this, email me.

Rob
[email protected]

This is a good summation of the problem, Rob, but Warp10's recent post seems to either indicate there's a #5 issue we haven't narrowed down yet, either that, or it refutes your "front panel" condition in your #4 issue.

Excactly! I've sent an email to rob with the following detailed description:

“The Bug”:
If I go to Settings->dimmer to adjust the brightness, The following happens:

Issue 1: Starting at 100%, down to 0%
The brighness varies RANDOMLY, which means If I go to maybe 60%, the display might be total dark.
Then, at 50%, the diplay might be as bright as 80% and so on.
Interesting thing is: If I am near 100% (90%, 80%) the display will be relativ bright, and if I am near 0%,
The diplay is relativ dim.

Issue 2: Starting at 100% trying to increase to ‘110%’
The brightness varies, but stays relative bright

Issue 3: AFTER showing the boot logo, the original brightness is not restored.
In the setting->dimmer menu the correct value was saved, but the actual brightness of
The display is just in the scale of the menu value.
And thats the issue why I cannot live with this, sometimes it just starts to dim! I then always
Have to go to settings and so on...

Note:
1. It doesn’t matter HOW I change the brightness (Knob, buttons, Remote), “the bug” is always the same
2. There is no temperature dependence.

Maybe it's a combination of the problems???

Well, in reference to #4 on your list. I am not just complaining that the dimmer doesnt adjust correctly. I am complaining because when my player is COLD and I start my truck (without me adjusting any dimmer settings) it picks a random brightness level to power up at. Then if I turn my headlights on, it will pick another random brightness level. Then I go in and adjust the dimmer setting and it is still picking random brightness levels until it warms up. I guess the biggest proble is when I start my truck up, I never know what brightness level the player will start out on.

Now, if the player starts up with my initial settions of 100% dimmer brightness and the player still isn't going to 100% even if I AM NOT ADJUSTING anything, doens't that mean there isn't a PIC argument going on. I don't see how you cant cool components individually. All you have to do is buy a can of cooling spray. Then you take a unit and go component by component and see which one is effected. At that point, a very small and cheap TEC could accompany that part. Also, they sell little tiny electronic warming "blankets" that could sourrond the part that doesnt like the cold.

You know what I just realized, I don't think anyone cares about this as much as I do. I am going to stop posting messages about this. If I try to investigate this myself I void my warranty. I guess if I buy an EOL product, I should just shut my mouth and be happy that I was able to get one of them while they were still available. Good luck to everyone! It was nice posting with you guys!

This is the most accurate description yet of my symptoms. The real issue is that in the car, at start up in daylight, the display sometimes is so dim that you can only adjust by feel (down, 4 lefts, down...). This is pretty messy. Frequently it will boot on AC at full brightness and then dim itself with no external inputs.

I do not see any temperature dependence but often I do see 60% brightness dimmer than 50% (just an example of "randomness"), in the car or in the house, regardless of which way I try to change it (buttons, remote, knob).

I have a Mk2A, 10 GB, 04010.... date code.

Has anyone brought out the VFD bias to a DVM to watch this signal during changes?

Lynn

Just to clear things up, I've got the problem which Rez and Warp10 describe. The annoyance is when I get in the car my dimmer will seemingly be at a random level, and when I toggle the headlights, it changes to another random level.

After the player has been on for 10 mins or so (and something has fixed itself due to temperature rising, I'm assuming) the dimmer works without fault, without exception.

My problem is definitely temperature related. I've tested this time after time now. It's possible that the other guys here with the problem aren’t affected by temperature, I could just be "lucky" and the component in question is affected between the 20-24 degree range. Theirs might start working at 60 degrees, who knows.

I noticed an IC on the display board, an AD8400 which is a digital pot. I'm guessing this is used for dimming, and it would be my guess as the suspect component. Tell me if this is crap, I’m no expert.

Anybody care to comment on the fact the dates of all the faulty players are all within a fairly short time period (6 weeks?)

Anybody care to comment on the fact the dates of all the faulty players are all within a fairly short time period (6 weeks?)

I would guess that about 2000 players were assembled in that period. The boards for almost all Mk.2A players were SMT manufactured within a few days of each other, and almost all components were sourced at exactly the same time.

I don't think that's an issue.

Rob

I've been looking at this on the scope and *may* have found the issue.

There is no separate chip-select line to the AD8400 dimmer chip, as we ran out of pins on the PIC. So, the CS is driven by an unused monostable from the clock line of the dimmer - when there is a clock, CS goes low and when the clock is absent for a while it goes high again.

There appears to be an issue that the R/C timing circuit for this is a bit close to the edge - ie, if the PIC is running slightly slow there will be a phantom rising edge on CS halfway through the dimmer setting byte - this is only ~20ns wide, but the dimmer chip is very fast and catches it.

The solution appears to be either to change the R/C circuit (hard, as it's under the display) or to add capacitance to the CS line to hide the glitch. On *most* mk2a players, the single chip on the back of the display board is a DIP 8400 (we couldn't source SMT ones for love nor money - they were used in some mobile phones, allegedly).

Anyway, if someone with this problem, a 10nF capacitor (SMT is ideal, very neat) and electronics knowledge/a soldering iron can try fitting it between pins 2 & 3 (ground and CS) of the AD8400 - ie, the middle 2 pins of the chip closest to the top of the display board, and see if this helps them. The one unit we've had returned which would repeatedly show this problem was fixed by this capacitor addition.

We're awaiting some more confirmation that this does address the issue before we do any warranty work.

Hugo

Thanks for taking the time to investigate.

Here's a pic of the (unverified) fix.



Hugo

My Player has an annoying bug and I should fix it myself?
Will I loose my warranty if I begin soldering? My player
arrived just a week ago!

I didn't suggest everyone fix it themselves; if you read my post I asked if someone with electronics knowledge wanted to help us verify the fix helped their player then this was what they should do.

When we have verified that the fix detailed above *does* cure the problem on as many units as we can verify it against, then we will start offering the fix to people who want to return their players for it. At the moment though, we have a very limited sample size and would like to check that we have actually nailed the problem.

Hugo

Again: Will I loose my warranty?

If you are competent to do this patch - and I do mean that, not "I own a soldering iron" then take this message as an authorisation to do it. Obviously, power off the player and check when you've finished that there aren't any shorts anywhere.

You will need to remove the drive cradle to get at the area with enough room to move. Ideally, remove the display board to reduce the possibility of dropping solder on the main board as the CPU is pretty close by.

Hugo

You guys are AWESOME. I'm really excited to get my player back. Thanks for fixing it!

Thanks for the heads up. I will make the mod to my unit. For anyone else willing to make this mod I would suggest using a thermostatically controlled iron with an isolated tip. Just my 2 cents.

I have performed the mod, and I can confirm it does seem to have fixed the problem! I will do more testing and report back later. I don't have SMT technology at home (who does!) but this cap went on just fine. Sorry the picture is so blurred.

I have also completed the mod with positive results. The Dimmer works great! BTW a .01uf is the same as a 10nf, for us State siders out there.

Of course, others have beaten me to it. So I'll just chime in: 10nF is the majic word! Works great!

Thanks for the suggestion!

It's easy, too: I didn't remove the drive sled. (Just don't burn the ribbon cable 8-)

Armin

Just to confirm my further testing, in-car this time. All working great, even headlight toggle works flawlessly

Thanks to the empeg guys for investigating (and providing a fix!) It will be interesting how many others are affected and either perform this fix themselves or get support to perform the mod (assuming they will accept this as a warranty repair)

My final question is though, what component(s) affect the timing enough to cause the problem in a small number of players, and be temperature dependant in some cases?

Additional: The fix also seems to have resolved the start-up dimmer level problem.

I suspect it's a combination of the R/C network and the ceramic oscillator - if the PIC runs slightly slow, and/or the R/C time constant is slightly too small the problem is seen. If *either* the PIC oscillator runs a bit quicker or the R/C constant is larger (bigger R and/or bigger C) then the problem is not seen.

The capacitor fix attacks the output of the monostable as opposed to the actual timing - the glitches still happen but the capacitor hides them. But... the fix can be done without removing the display.

I'm glad that the fix appears to have worked for everyone, pity I didn't find the glitch about a year earlier! One issue was having a unit which exhibited the problem 100% of the time (hot or not) in my hands - when I had this it became a lot easier!

Hugo

Add me to the count also! MK2a sn# 040104150 running 2.0b11. I've had the player for almost 2 months and just noticed the problem earlier this week after running 2.0b11 for several weeks.

Without making ANY adjustments to the unit, sometimes display is very bright (100%) when I dock the player in my car after work and sometimes the display looks around 80% ish.

After discovering this thread I decided to dock my player in the car and have a look at it (I've been listening to the player for a couple of hours in my office) and the dimmer seemed to be VERY dim. I checked the dimmer setting and it was at 0%!

Perhaps it is a temperature issue?

-Chris

Just posted earlier regarding this but this post caught my eye.

I ALSO have a 30GIG inspected by EP with a serial number of 0401.

Interesting if nothing else.

-Chris

I checked the dimmer setting and it was at 0%!

I do not believe that this specific exact precise problem (dimmer set to zero in the menu) is the same thing as what's being discussed in this thread. That would be a different unrelated problem caused by the player's flash RAM getting hosed (I think).

The problem being discussed in this thread would result in the dimmer setting in the menu showing 100 percent, but the actual brightness of the display being random.

At least I think that's the case. I could be wrong. Anyone?