DX7 IIFD issues [SOLVED]

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radek tymecki
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DX7 IIFD issues [SOLVED]

Post by radek tymecki » Mon Dec 29, 2014 8:52 am

Hey. I've bought used DX7 II FD with case and 3 cartridges from NL. previous owner told me that there were "chinese fonts" on lcd after removing dead battery. after picking it i've managed to exchange it to new one [cr2032]. the synth boots but i get no sound and still there are issues with lcd. i dont know how to check if everything else is ok as nothing changes on the screen, but i can use all the buttons etc. the synth also rememberts last program i've been using. what can be wrong?

ps. voltages are ok

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Last edited by radek tymecki on Tue Jan 13, 2015 9:19 pm, edited 1 time in total.

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Re: DX7 IIFD issues

Post by db0451 » Mon Dec 29, 2014 2:14 pm

Simplest thing is to check the cable connecting the LCD to the mainboard.
but i can use all the buttons etc. the synth also rememberts last program i've been using.
so you mean it is responsive, and the segmented LED numbers change, but just not the main screen?

Absence of sound might just be a settings problem – corrupted memory from the previous dead battery could have set master volume to 0, or applied a nonsensical key range limit, or anything. All settings should be reset, but obviously it is not easy to do that when you cannot see anything :/

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Re: DX7 IIFD issues

Post by ranzee » Mon Dec 29, 2014 3:45 pm

Did come with the Factory ROM Cartridge?

Perhaps you could run "blind" the factory restore procedure, see if that works.

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Re: DX7 IIFD issues

Post by radek tymecki » Mon Dec 29, 2014 4:25 pm

i have memory cartridge. when switching to it i can hear some sounds so LCD is the only problem now

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Re: DX7 IIFD issues

Post by radek tymecki » Mon Dec 29, 2014 9:29 pm

cables seem to be ok. deassembled synth, connected ribbons and still lcd is dead.

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Re: DX7 IIFD issues

Post by db0451 » Mon Dec 29, 2014 9:43 pm

Need to check solder joints etc too. Garbled characters would tend to indicate some sort of digital glitch, perhaps one or more dropped bits, which could occur for various physical reasons. Also check the schematic for any sundry buffers, etc that might be between the CPU and the LCD, as if present, they might be faulty and causing corruption in the data.

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Re: DX7 IIFD issues

Post by radek tymecki » Fri Jan 02, 2015 11:51 pm

ok i'll check that and keep ya updated

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Re: DX7 IIFD issues

Post by radek tymecki » Tue Jan 13, 2015 9:19 pm

fixed! lcd was faulty. bought new one and everything works

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Re: DX7 IIFD issues [SOLVED]

Post by amustsuccess » Tue Apr 07, 2015 11:20 pm

Hi Guys!

I have a DXIIFD, but at the moment it sounds horrible. For every chords and note played, there’s distortion and noise that accompanies the sound. Please, what can be done to rectify this problem? Cheers!

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Re: DX7 IIFD issues [SOLVED]

Post by Weirdofromouterspace » Wed Apr 08, 2015 10:56 am

Hi and welcome,
amustsuccess wrote:I have a DXIIFD, but at the moment it sounds horrible. For every chords and note played, there’s distortion and noise that accompanies the sound. Please, what can be done to rectify this problem?
First of all, it might've been a good idea to start a new thread for this instead of posting in two solved ones ;).

Anyway...

The least problematic situation is simply corrupted/damaged presets due to a dying battery. You can check that, of course, by loading some sample patches into the synth via a sysex dump. If it then sounds fine, replacing the battery will most probably solve the problem.

If not... take the synth to a tech :-?, since I reckon you wouldn't have asked if you'd be able to check the pcbs and find faulty components by yourself ;).
Don't forget to TURN ON THE SYNTHESIZER. Often this is the reason why you get no sound out of it. - ARP 2600 manual, 1971

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