NEC Firmware upgrade error

**Leo Enticknap** · 05-21-2026, 07:00 PM

We are totally sure that this is a CPU board, part 81T19C03, that has been replaced? I ask, because the ICP (7N951811) and motherboard (81X15M01) are unique to the NC900, and cannot be taken from other Series 2 NECs. This is because is a physical line, for the lamp sync signal going from the ICP to the ballasts, is present on the NC900 variants of these boards, that is not on the variants intended for all other Series 2 NECs.

Assuming that it is the CPU board we're talking about, did you do the serial number maintenance step before trying to update it?

image.png

The last time I replaced a CPU board in an NC900 was on September 15, 2022: I've just checked my service report from my call, which notes that, per instructions from NEC, I had to do two things: that serial number maintenance step to enable the tamper to clear, and then setting the option slot setting to "no board," booting the projector fully, back into standby, changing the setting to IMB, then boot up again, to enable the IMB (a GDC SX-3000) to marry.

If I remember correctly, when you press check, it will tell you that the serial number of the new CPU board does not match that of the projector, and ask you if you want to sync the two. After you've done so, you can clear the tamper and then do the software/firmware update via DCC in the normal way rather than have to mess around with USB sticks.

**Armand Daiguillon** · 05-21-2026, 08:19 PM

I was told by Strong that the update can only be done by USB - which seems to be correct since the DCC can not even log in. After the unit detects that the board is not working, it shuts down to a point that dcc can not communicate.

The process to update the board is to turn on main power switch while holding the "exit": button. Then release and press "exit" again. then press up arrow - that forces it to load the first update. When doing this it does "try" to update then we get the error. The second step repeats everything same as first except instead of the "up" arrow - you press menu - this loads the second update from usb.
Both however fail with similar errors ....
Also i'm pretty sure it's the correct board - I tried to get from MIT first but they did not have stock and no ETA on availability, so then I found it locally (used) but when it didn't work assumed it was incorrect board, then contacted Strong that then sent the exact same board (had a used one in stock) and they said it was not working because it needed the firmware and software upgrades specific to the 900C since this particular board is same in several projectors.

It's all very frustrating - it should simply be taking the updates ....i'm missing probably some minor 1st step ....

**Leo Enticknap** · 05-21-2026, 08:31 PM

Will DCC communicate with the board at all? The factory default IP address is 192.168.10.10 / 24, but if it's previously been in another projector, it may have another address, and you'd need to find it manually (e.g. using Wireshark).

I've just checked the service manual and the slides from the NC900 service training. The only USB procedure mentioned is downloading a log onto a USB stick: I can't find any info about the update via USB procedure you describe - sorry.

**Armand Daiguillon** · 05-21-2026, 08:46 PM

Originally posted by Leo Enticknap

Will DCC communicate with the board at all? The factory default IP address is 192.168.10.10 / 24, but if it's previously been in another projector, it may have another address, and you'd need to find it manually (e.g. using Wireshark).

I've just checked the service manual and the slides from the NC900 service training. The only USB procedure mentioned is downloading a log onto a USB stick: I can't find any info about the update via USB procedure you describe - sorry.

The dcc can not connect if there is no board or if the board is not set up with correct firmware.
Its this firmware update on the cpu pwb thats the issue.
And i looked at service manual too - there is nothing there about the firmware updates to this specific board.

So frustrating...... I appreciate your trying !!

**Tj Hopland** · 05-22-2026, 06:48 AM

I don't recall reading about or doing USB updates on the S2's but on the 1's there was a stick size limit. I don't recall what that size was but remember even back in say 2012 I had to search to find one small enough. I think file format was specific and there were specific file names in the root directory.

I just dug through by computer bag and found the one I used for S1's Its a 1GB, Fat32. And the only files in the root directory are _pjfirm! and _pjdat!.

Series 2 could have been different and as noted the 900 had its quirks that were different than the rest of its family but it was all the same family so those older rules could still apply especially since this was more of a recovery procedure so maybe they didn't bother to 'update' it to support newer at the time sizes and formats.

**Armand Daiguillon** · 05-22-2026, 03:52 PM

Originally posted by Tj Hopland

I don't recall reading about or doing USB updates on the S2's but on the 1's there was a stick size limit. I don't recall what that size was but remember even back in say 2012 I had to search to find one small enough. I think file format was specific and there were specific file names in the root directory.

I just dug through by computer bag and found the one I used for S1's Its a 1GB, Fat32. And the only files in the root directory are _pjfirm! and _pjdat!.

Series 2 could have been different and as noted the 900 had its quirks that were different than the rest of its family but it was all the same family so those older rules could still apply especially since this was more of a recovery procedure so maybe they didn't bother to 'update' it to support newer at the time sizes and formats.

I was given a more complete set of instructions on the whole process by someone else in this forum, what Strong sent me was incomplete .....the directories you note are the same as in the instructions I just received - the spelling of the directories Strong gave is slightly off and could also be why updates failed. (they left out the underscore character) - we'll be trying it again later tonight, i'll update with results.

Thanks

**Armand Daiguillon** · 05-25-2026, 03:44 AM

I'm happy to report that thanks to assistance received here, everything is back up.
The instructions Strong's support sent me were wrong .... they misnamed the directories that needed to be on the usb stick for the updates to be recognized. Once they were corrected the updates went through no problem ....Strong also neglected to mention the backup process that should have been done first and also failed to mention the issue Leo brought up about the serial # mismatch. Luckily in the end it all worked out.

Thanks all !

Armand

**Leo Enticknap** · 05-25-2026, 11:20 AM

Good to hear that you got it back up.

If you get a moment, is there any chance that you could write up a precise, step-by-step set of instructions on this thread (including the exact filenames and directory structure needed, and the USB stick partition and volume format that is known to work) in case anyone else has to troubleshoot the same problem, as I did here? Google and ChatNFG will then likely ingest it and guide anyone who searches the net. This would be especially helpful, because this procedure is not documented in either the service manual or the slides from the service training class (which, in my experience, is a known issue with NEC and GDC especially). I would guess that this is why the Strong tech who advised you misremembered the procedure and wasn't able to give a complete and accurate description of it.

I'm guessing that at that call in 2022, I didn't have to update a CPU board via USB, because the replacement board I installed was new and intended for a 900, and therefore shipped from NEC with the correct firmware already in it. But given the part availability situation for older Series 2 NECs now, I think it's quite likely that people will need to take boards from other models of projector to keep a 900 on life support (or vice versa) in the future.

**Armand Daiguillon** · 05-25-2026, 05:01 PM

Here is the documentation that was shared with me .....

CPU replacement procedure.pdf

**Marco Giustini** · 05-26-2026, 11:57 AM

OT

Now that AI is getting common, do you think NEC will be able to improve on the quality of their documents?

The attached is the PDF Armand attached, passed through Claude to be reformat and rewritten. I haven't compared it 100% but it looks like a good starting point!

Attached Files

CPU_replacement_procedure_revised.pdf (287.8 KB, 10 views)

**Tj Hopland** · 05-26-2026, 08:17 PM

Maybe AI was how some critical information got dropped from the earlier version of the procedure mentioned here?

**Marco Giustini** · 05-27-2026, 03:27 AM

I doubt any AI would write

During push 'Exit' button, turn on the projector.

**Fraser Falconer** · 05-27-2026, 05:58 AM

Hi Everyone,
Interesting, That Document was included the information covered by the NEC NDA when I went to NC900 school. Pleased it's all go.

Cheers Fraser

**Leo Enticknap** · 05-27-2026, 09:28 AM

Thanks to Armand for posting the cheat sheet; filed for future reference. I'm starting to feel strongly that it's important for us to gather and keep hold of info like this. There are lots of theaters out there with older Series 2 projectors and no financial option other than to try to keep them alive for as long as possible. Procedures like this that aren't documented in the main service manual and training documentation are in danger of getting lost, especially as manufacturers discontinue formal support offerings for model ranges. At that point we're down to informal help from those companies' veterans, and whatever reference material we've gathered ourselves.

Originally posted by Marco Guistini

Now that AI is getting common, do you think NEC will be able to improve on the quality of their documents?

IMHO, the Claude version is a classic demonstration of both the strengths and weaknesses of AI. It gets it 99% right, and is definitely easier to follow. However, I did see at least one glitch:

image.png

Claude also preserved my favorite entry in the NEC Jinglish dictionary - the infamous "service man mode." One female tech I know jokes that she's afraid that DCC will reject the passcode unless she cross-dresses before trying to log on.

NEC Firmware upgrade error

NEC Firmware upgrade error

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment