Monitor board issues - dm4800

[warpdriveprod]

Seems like my talkback dimmer function on the monitor board is going haywire. The LEDs will randomly flash and/or stay lit for DIM, TO SLATE & TO STUDIO. I've gone into the monitor screen and set the dimmer to zero as a temporary workaround so I can mix, but I'd really like to get this resolved. Tascam says I could try a factory reset and if that doesn't work, bring the board in for repair.

I did the factory reset from the diagnostics screen (powering up while holding down shift, and output assigns 1 & 2). It seems all that did was wipe out all my settings that were in system memory. Did I do this correctly? It did not resolve the problem. Perhaps I didn’t do it correctly? Anyone?

Is there a history of this issue? Is this something I can repair myself?

Any input would be greatly appreciated. Thanks!

 

[captdan]

First I've heard of this problem. My first thought would be that there's something affecting the DIM/Slate switch; perhaps some dirt or crud that somehow got in there causing intermitent contact. Long shot, but if you can put a strong light and magnifying glass to bear, it might be worth a look. And, if something is stuck inside, maybe a small shop vac with hose could suck it out.

The next step would be to open the console lid and check the switch and cabling. There's a likelyhood something could be loose on the switch board.

PS: Welcome to the Forum. Is Aliso Viejo somewhere east, south, or in the vicinity of Orange County?

CaptDan

 

[warpdriveprod]

Hey captdan, thanks for your insight. Yes Aliso Viejo is a new city in Orange County between Laguna Beach, Laguna Hills and Laguna Niguel.
My take is that the problem is not likely due to a mechanical switch as my board is in pristine condition and the events occur when doing nothing, so I suspect it is caused by something electronic. I will be cracking the thing open soon to have a look. At first I suspected some MIDI events, but after filtering MIDI controller data and/or just disconnecting MIDI cables, there was no change. The tech at Tascam also told me there is no MIDI implimentation of the monitor board. So I suspect a bad capacitor, solder connection, connector or something like that. We'll see.

Oh, and I used to be a member of the old messageboard until it disappeared for awhile, so I'm just returning. Glad to see it's back up and running!

Marc

 

[Arjan P]

If your Talkback function is also assigned to the footswitch input (whether one is present or not) this may also be worth looking at..

 

[philrl9]

Hi,

Did you ever get this issue resolved? I picked up a used DM-4800 in what appears to be pristine condition, but am experiencing the exact same issue. I've also done a factory reset without issue.

I was hoping to not have to crack the board open.

Thanks!

 

[warpdriveprod]

Yes it has been resolved. I did not crack it open until I first spoke with Tascam. They were very good about it by honoring the warrantee even though it was almost 2 years old. This is because I explained to them that the unit has never been moved since it was first set up, nothing changed.

I drove it out to the service center in El Monte, CA. They determined it was a loose ribbon cable and took care of it, no charge!

There you go!

 

[cmaffia]

Great ending to this story and great to see Tascam going above and beyond yet again.

Long live Tascam!

 

[welchwelch]

I am also having the same problem, it took me a while to figure it out, I would be listening to a something then the volume would drop, I look and dim studio and slate lights would be on I would turn it off and everything would be alrite, then a few minutes later it would do it again. I guess I have to see if there is a loose cable on mine.

 

[warpdriveprod]

Yup, that's it!

 

[darthfader93]

I also have this same issue except for my audio will drop in level after I playback for awhile and it will sometime distort. I have it cracked open but I don't see anything loose. I guess I will have to take off the monitor pcb itself and see what's wrong

 

[Russ Nixon]

I stumbled upon this old thread while looking for help with this same problem. My pristine 2 year old DM4800 just started doing this today! I'm most thankful to user warpdriveprod for the quick workaround solution, and for sharing the long term fix. I guess I'll open it up and see if I happen to find a loose cable. I live in the middle of nowhere, so getting it serviced is a fairly major undertaking. Thanks once again to this community for the support. Here goes nothing...

 

[rtteter]

I'm having this problem! What's the quick workaround you mention? Mine was bought used so tascam won't help me

 

[cmaffia]

Check the ribbon and disconnect/reconnect to the monitor PCB board. He says the temp solution is to set the dimmer dB to zero so that when it spontaneously triggers, you won't hear the volume fluctuation. If it's not the ribbon then you'll have to send it in for service if you want it repaired properly.

 

[Hiaddiction]

My dm4800 has just started to do the same thing. How do you open up the console to find the ribbon? Also where do I find the dimmer you were talking about. Is it a digital dimmer or the monitor dimmer? Thanks please help

 

[Hiaddiction]

Any idea which ribbon cable it was, I opened it tried a couple same issue happening.

 

[demon_beats]

Reviving this old thread as my DM4800 has just started experiencing output problems: using Large monitor outputs for playback, right side will increase/decrease volume, left side will sound distorted even at quiet levels; no output from Small monitor outputs; headphone outputs have reduced output, increased distortion, and intermittent playback. Haven’t noticed any blinking lights, yet.

Does anyone have pictures/video of what it takes to repair this output problem? Can anyone confirm part #’s (pcb board, ribbon cable) for the fix? Are there other parts that would effectively “upgrade” the output pcb?

I’ll create a video to document the repair process, as other users are sure to experience similar problems with their 4800s in the future.

Thanks in advance!

 

[demon_beats]

Update:

After removing the requisite screws, I flipped the upper section of the DM4800 open to get a closer look at monitor output section.

The multi-coloured ribbon cable that connects into the bottom of the monitor output PCB was sitting on an angle, rather than flush, with the board itself. Upon closer inspection, one side of the ribbon terminal end had started to disconnect from the PCB board receptacle. Simply re-seating the ribbon cable terminal end to the PCB board fixed the problem. While I had everything open, I sprayed the cable terminal end with control cleaner (Nutrol by MG Chemicals). I am happy to report that all monitor outputs are working good as new!

It is very likely that physical vibrations from studio monitors can shake that ribbon cable loose over time. In operation, gravity is also working against that connection because the ribbon connects to the bottom of that monitor PCB. If the cable comes loose again, I’ll use a hot glue gun to fasten the ribbon cable terminal more directly to the PCB receptacle.