ssp

picked up an old mb_lc

13 posts in this topic

Picked up an old midibox lc off ebay cheap, it powers on fine and seems ok.

Its not a unit that I am familiar with but its something for me to tinker with in these winter evenings.

Couple of questions,

1: the core's are old home made cores , I still have a couple of smash tv's core 8 pcbs here, can i replace the others with those, I am assuming i can

2: the MF was replaced with the MF_NG so I am going to buy one of those to replace the old MF pcb  I see this can be linked to the pc directly rather than the cores. Anything else i should know on this replacement?

Plan is the put one of my old GM5 midi interface boards in there and have the MF_NG and the cores midi route into that then out via usb as i have done on previous projects.

This one boots up with the message logic control emulation, is this the same protocol for use in Mackie HUI mode or is it a different set of settings i cant for the life of me remember if the logic protocol is the mackie protocol or if its a different settings hex file that needs to be uploaded for it to be a mackie HUI configuration.

If anyone still has an old LC kicking around or has modified theirs to a better setup I would love to chat about it and pick some tips up while i tinker with this. The wiring needs re-newing and the casework is going to be media blasted and powdercoated in the meantime.

 

Thanks

 

SSP

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All is good i have managed to dig up all the old information scattered over the forum pages and other places.

There are two professionally produced pcbs in this thing that i still have not found out any information about yet, i will put up some pics incase someone may be able to help, other than that im fine, it all came flooding back and im already working on the casework and upgrades.

 

Thanks

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bit of a head pickle here,  i have one of the 40x2 lcds connected to a good core that i use for build tests.

With my usual lcd attached all is fine in backlight and contrast.

I have connected the 40x2 and the backlight is good however the lettering is very very faint, contrast seems to have no effect when i turn the pot other than it dissapears.

my core has the 7805 vreg on, i am just wondering if its not getting enough voltage, it displayed good on the old core board from the unit, but it was covered in really bad soldering.

there are new connection pins on the lcd and i have measured the voltage from both pots p1 and p2 and i get the correct voltages.

checked the link cables which are pushon with the multimeter and all is good.

 

bit strange this one.

 

The lcds are the TM402cd from tianma   https://www.beyondinfinite.com/lcd/Library/Tianma/TM402CBCWVBYA.pdf

 

connection is standard.

 

any ideas?

thanks

 

 

Edited by ssp

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OK this is weird if I turn the core on and off I randomly get the display graphics come up for a fraction of a second then go back to being really faint. Contrast makes everything dissappear still. 

Screenshot_20191117_201521_com.huawei.himovie.overseas.jpg

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there is no datasheet for this model anywhere however, looking at close variants the v0 needs 0.3v negative feed.  Seeing as these are old lcds anyway I am going to change them out for a pair of new winstars

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What LCD driver is set in the Core bootloader? Maybe check that?

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I used the original core from the mblc it's the v0 pin it wants a neg 0.3v link. This old lc had a separate power link board that gave it that. Had a dig around it last night. They are very old displays now, much better options are available now. Replacements arrive tomorrow I am just playing with this until my other parts arrive from modular addict. Making a newer controller with the new mf board etc. I just wanted to have a fudge with this old mblc 

 

Edited by ssp

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The new displays turned up today, all is good. Working first time, the old ones will be used for something else. I have a load of stuff on order from modular addict.  Need to build a few controller's for the studio.  

IMG_20191119_175232.jpg

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i picked up a pickit 3 programmer and made a pic socket link pcb in work. uploaded the bootloader to the pic then mios and all was good ;)  its been a while since i was here and its all coming back!! hurrah!

just have to wait for my bits to arrive from modular addict which is always the bit that is annoying, i remember waiting for kits from smashtv!!

the picture above was from an old core and wasnt displaying properly on the new lcd, a quick bit of code and all is well again, no spaces etc.

I am trying to find out the details on the pcbs that were inside the unit and also details on the layout on the Holt case that it came in.

If anyone has any details on the boards let me know!.

 

 

 

 

Screenshot_20191119_201014.jpg

Edited by ssp

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Fancy! If these are custom PCBs they would've been very expensive back in the day!

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the boards are well made, plenty of connection identifiers in the silkscreen, some led connections are missing and they are soldered to pads under the pcb and wired around it which i will sort out in work by adding some connect pins.

 

There is no info on these boards on the server, i did notice that Dan D2K used them in his mblc units but there is no info there in the forum thread, its old and any links are long gone, they are easy to understand the circuit paths etc but more info would be good as well as placement and position etc from a new front panel, I am hoping the Holt who did the original case still have some details.

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Just got my 2x40 link pcbs that I had made. These allow me to connect the two lcds I got to the one board and link via ribbon. E2 has a jumper to allow the second enable line to link through or be separated. 

IMG_20191130_144134.jpg

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