Help me fix my DEQ2496 please...

[MikeHunt79]

It was working fine until recently, and now just the display backlight (and the optical out led) comes on and it does not boot...

I'm guessing the first thing to do is check the voltages from the PSU, but if these check out to be ok what would be the next thing to do?

EDIT: Also, what's the VR1 pot for? Display contrast?

EDIT2: The PSU seems to be putting out the correct voltages, what else can I check?

[rossl]

the connector from the power supply to the cpu board is bad on some of these units.

pull off the connector at the cpu board and make sure the crimps are good.

that's the first thing I would do.

[MikeHunt79]

Originally posted by rossl
the connector from the power supply to the cpu board is bad on some of these units.

pull off the connector at the cpu board and make sure the crimps are good.

that's the first thing I would do.

Ok, I've done that. I also measured the voltages again this time from the CPU board, and they check out OK. I'll see if I can check the regulators on the CPU board also....

[zanash]

contact tenson on zerogain.com ....he mods these units and must know all the bad things that can happen .....

I've a deq 2496 but have only mildly worked over the units psu and its always worked fine ...

[kepa1]

I know that the connectors from the Input/Output board to the mother board of the DCX2496 have flaws, so it might be the same on the DEQ.
To solve that, you could replace the flat cable or simply bend the male connectors to get a better contact.

[FrankWW]

DEQ 2496 not booting.

You may get lucky - simple fix.

The main circuit board can 'short' against the bottom of the case. I've seen two cases like this.

Before you do anything radical, turn on the machine, pick it up and twist it, see if it boots then.

Or, just slide a piece of thin cardboard - like used for greeting cards - between the board and the bottom. See what happens.

[MisterTwister]

I remember mine didn't work without top case cover touching power supply's top metal screen. If I remember correctly I just bent that screen, so it has better contact with top case cover. it fixed the problem.

[MikeHunt79]

Originally posted by zanash
contact tenson on zerogain.com ....he mods these units and must know all the bad things that can happen .....

I've a deq 2496 but have only mildly worked over the units psu and its always worked fine ...

Thanks, I'll get hold of him. Hopefully he will be able to tell me the most common things that stop the DEQ from booting up.

Originally posted by kepa1
I know that the connectors from the Input/Output board to the mother board of the DCX2496 have flaws, so it might be the same on the DEQ.
To solve that, you could replace the flat cable or simply bend the male connectors to get a better contact.

I've actually tried it with the IO board disconnected and it still doesn't boot. The cable it self seems ok tho.

Originally posted by FrankWW
DEQ 2496 not booting.

You may get lucky - simple fix.

The main circuit board can 'short' against the bottom of the case. I've seen two cases like this.

Before you do anything radical, turn on the machine, pick it up and twist it, see if it boots then.

Or, just slide a piece of thin cardboard - like used for greeting cards - between the board and the bottom. See what happens.

I removed all the PCB's and covered the case in tape, apart from under the SMPS, as you can see here:

Originally posted by MisterTwister
I remember mine didn't work without top case cover touching power supply's top metal screen. If I remember correctly I just bent that screen, so it has better contact with top case cover. it fixed the problem.

That's weird, because mine has a plastic sheet on the top cover around the PSU area which looks like it's designed to insulate the top cover from the screen. Did you remove this plastic cover or did your not have this cover at all?

[MisterTwister]

I don't remember exactly. I need to open my unit.
You may check if it will work by shorting power supply's cage to the case, with screw driver.

[MikeHunt79]

Originally posted by MisterTwister
I don't remember exactly. I need to open my unit.
You may check if it will work by shorting power supply's cage to the case, with screw driver.

I tried shorting it with a screwdriver, still no boot.

I think it may possibly be the BIOS chip, 39SF040, I actually have an EEPROM programmer so I'm going to see if I can get a blank 39SF040 chip and flash the firmware to it. The only problem with this is that I'm not sure where I can get a firmware file from, Behringer have the updates for the DCX (as it's updatable with the RS232 cable), but none for the DEQ.

EDIT: Found the files on the Behringer site after all... All I need to do now is get hold of the blank EEPROM.