DM4800 CF card unit

Thank you so much for the quick reply! I understand you are just being helpful and not a technician.

It sounds like maybe I should start by pulling and replacing the Main Board and then hope maybe my CF card unit is not permanently damaged. If it is, I will have to start searching out a third board for that...

Is there a source for getting a main board replacement unit? I'm pretty handy inside the machine so is this a rather simple card swap installation or is it a major headache to do oneself? I should also ask, how much does a Main Board cost?

Thanks!
 
See my eBay link above
 
Thanks for sharing that! It's just what I needed.
 
We purchased the replacement Main board from Ebay (thanks for the link). Today, I opened the DM48 to remove the old main board and replace it. I used the photo instructions from the full dismantle link above. This was very straightforward. There's lots of room inside the DM4800 so it was pretty simple to disconnect everything and pull out the main board. The 32-pin socket and connector for the CF card board were clean and fine.

All went smoothly except one pair of ribbon cable connectors from the MIDI board and the Sync Board. Both of these 26-pin connectors had corroded and glued themselves to the pin socket on the main board. After much careful work I was able to remove the connectors but with each of them, one of the pins had adhered between the connector and the socket and in each that one pin broke off inside the connector flush with the edge. Impossible to get the pin out. I have attached photos to clarify this.

It's easy to get new connectors for these two ribbon cables (FC 26P female connectors) and the pin sockets (P7 and P8) on the replacement main board are clean and shiny so I think it should be OK for the rebuild. But I am wondering if anyone knows why these two connectors, and only these two on the main board, had gotten into this condition? Also, could this be the reason for my original problems with the CF card and the MIDI input errors (see my questions above)?

Below is the view in from the back of the mixer looking down at the main board showing the pair of connectors from the MIDI and Sync PC boards. These are the two that gave me trouble.
IMG_3302.jpg


When attempting to pull out the connector at first, the top piece broke off and revealed a pretty messed up connection.IMG_3312.jpg

Here are the two 26-pin sockets on the old main board after prying out the connectors. Note that in each of them there are missing pins, which broke off inside the connector when it was pulled off. Note also the red and green grunge in the sockets. The replacement main board has clean and shiny sockets and pins here.IMG_3317.jpg
 
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Just my two cents. Looks like someone may have already tried securing those connectors at some point.
 
We bought it new seven years ago. Do you mean a factory kludge, P. Batah?
 
If you are the original owner then perhaps an adhesive was used to keep the connectors snug. Similar to lock nut. It may have been a process that was used at the manufacturing / assembly level. Someone on the forum who has disassembled the unit may be in a better position to provide you with a more accurate assessment. Best of luck I hope that everything works out in the end
 
Thanks for your good wishes! Is it because of that red or green stuff you say it was secured in the assembly?
 
It's a possibility.
 
Does the CF reader work now??
 
OK. I have installed the replacement Main Board.

Good news first:

The mixer boots up and the CF card is now working correctly.

Bad news:

The mixer now thinks it's a DM3200 instead of 4800 and many functions (output assigns) fader-associated SEL-SOLO-MUTE buttons for 1-48, and the encoder mode buttons) do not respond and the buttons are dark (lights not responding when pressed) even though on startup all the LEDS flash in the startup routine. SEL buttons for 9-48 cause the faders to move to unity gain position but do not allow for output assignment, etc. I have not programmed any i/o yet so perhaps it's because routing is not programmed yet but I need the mixer to think it's a DM4800 in order to set the i/o assignments.

It's a DM4800 main board. The Main Board silkscreen printing shows this for the ID:

TEAC
E902855-00B
PCB,
MAIN DM4800 G
sn • Ag • Cu

The original board ID that I removed is:

TEAC
E902855-00C
PCB,
MAIN DM4800 G
sn • Ag • Cu

The only difference is the "00B on the new one as opposed to "00C" on the original.

I looked carefully for any jumpers labeled "make this a DM4800" on the board but couldn't find anything that simple. :)

Because the output assign buttons don't work, I can't do the factory reset Shift + Out 1 + Out2 technique to reset to factory.

I thought perhaps all I needed to do was update the firmware but when I tried it the Mac DM Companion software sees the mixer as a DM3200 so it won't install the DM4800 firmware.

I am really hoping someone on the forum knows a way to teach this main board that it's installed in a DM4800 so I can make it work again. All help is greatly appreciated!

Bill
 
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Did you try the "forced system update mode" ? Not sure this will solve it, but worth giving a try.
The procedure is discussed in the dm3200 service manual part 2
 
I haven't tried that yet. Thank you, Olietyven. I will give it a try.
 
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Procedure 1. Switch off the DM-3200. 2. Hold down the right-arrow cursor and ENTER keys and switch on the DM-3200 and "SYSTEM UPDATE MODE" is displayed in the upper center in addition to the normal startup screen. 3. When the TASCAM Logo scrolls to the end, the screen is switched to show a screen in the center of which "SYSTEM UPDATE" is displayed wide. 4. Now update the firmware from the TMC by following the steps discussed under "1. Firmware Upadate".

Not sure if that addresses the problem as he said the firmware won’t take because it thinks it’s a 3200. This procedure seems to be for failed or interrupted firmware updates
 
I studied the motherboard closely, and there seems to me no swappable eproms, witch lead me to the fact, that the dm4800 firmware/systemsoftware needs to be flashed somehow.
 
May need to be sent to Tascam HQ to perform flash. I would just call them. Maybe RedBus will see this post before then and confirm.
 
I tried to do the SYSTEM UPDATE procedure but the Tascam Companion software still sees the mixer as a DM3200 so the DM4800 1.7 firmware file can't be uploaded to the mixer. I did update to DM3200 v.1.7 but that didn't help. I have a request in to Tascam Service to ask how to address this but in the mean time if anyone has any ideas for flashing DM4800 data to the ROM, I'd really appreciate it.
 
Never write to Tascam!!!! Call!
 
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