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[MrMOUSE]

Does anyone have a clue as to how to reset the factory presets on the drumulator 7000 series?  Thanks

[Gordonjcp]

Load them in from tape.

[MrMOUSE]

Does anyone have a clue as to how to reset the factory presets on the drumulator 7000 series?  Thanks

thanks but there IS a secret command on that board to load them plus where would one get the tape?  Thanks!

[Ciderfeks]

Did you make any progress with your search MrMouse? I am also trying to revive a seemingly dead Drumulator and making slow progress. I have learnt a few things though which might be useful to you...

If you are getting the BAd error message at start-up you can try clearing all memory using the following button push sequence, but remember this will wipe any patterns you may have stored:

Switch on.

Press the song/segment button so that the segment mode is selected.

Hold down the Insert/Erase button and press the Cassette button once, do not release the Insert/Erase button.

The message "poof" appears in the screen (no, really).

Whilst still holding down Insert/Erase press the Enter button.

Switch off and on again - all memory should now be cleared and the BAd message should be gone and the Drumulator should work normally.

It's also worth changing the internal battery as they were only meant to last for 5 years or so - you need a 2/3 AA, 3v Lithium battery with solder tags (2 tags not 3).

Unfortunately I have gone through the above procedures and got the machine to function as expected just with no sound other than the metronome. I've adjusted all the levels so now I'm thinking that maybe the eprom has been wiped or something and they're gonna need re-loading from tape and as you said - where do you find that?

[Gordonjcp]

You can get the drumulator service manual from here:
http://manuals.fdiskc.com/flat/

Page 35 has what appears to be the audio DAC, which is passed to another DAC which acts as a gain control.  You could try listening at the output of the 6072 DAC and seeing if any sound comes out, then trace it forwards through the gain control, multiplexer and output buffers.

[Ciderfeks]

Hi Gordon, thanks for your reply, I'll certainly take a look into that. I've only just seen your reply actually - for some reason it wasn't picked up in the "show replies to your previous posts" section that I usually go to first when I log on here, so I just chanced upon it now.

When I opened up the Drumulator, there was some dodgy looking repairs and mods that had been carried out buy a previous owner which I have been slowly going through and returning to normal but still no go, but I have some suspicions....

I am wondering if the problem may be with IC 9B (LM 3086N a transistor array?) which had a diode added, bridging pin 7 and 8. There are signs of heat damage to the surface of the IC where the diode had been.

There was also a repair to pin 1 of IC 12A (CP8251) but as yet I cant find any info on that one. Hopefully the service manual will help. The pin had been pulled from the board and hard-wired to one leg of 3 nearby components, but with no obvious trace damage between those components and the IC, I don't know why this would have been done.

I'm waiting for the service manual to download now...

[Gordonjcp]

When I opened up the Drumulator, there was some dodgy looking repairs and mods that had been carried out buy a previous owner which I have been slowly going through and returning to normal but still no go, but I have some suspicions....

Are you certain these were "dodgy-looking repairs"?  There were *masses* of ECOs for the Drumulator, which consist of cut tracks and bridging wires, and extra components tacked on here and there.  Without these, you haven't a hope in hell of getting it running!

[Ciderfeks]

Yes, indeed - a quick glance at the service manual when it arrived showed that two of the "repairs" were in fact ECO's (namely the diode added to IC 9b and a bridged cap at C75). These will be going back in, but looking at what they do in the notes, they shouldn't be critical even with them reversed? The machine didn't work with them in place either  Interestingly the service manual showed up an ECO for my revision that hadn't been carried out, but first things first...

This project is currently beyond my capabilities really but I've been meaning to learn about fault finding and how to read service manuals  so this could be the place to start, but it will probably be slow going. One thing that does look somewhat worrying is that the traces look like they've crinkled and raised in places - a bit like wrinkled tin foil. Its difficult to tell whether its the trace or just the blue masking layer. The continuity doesn't seem to be affected but the machine has been stored in a shed for years apparently, which has got to hurt...

[Gordonjcp]

You do get that wrinkly effect, as an artifact of wave soldering.  Don't worry about it, but be careful soldering near it.  It should really only be an issue on large areas of copper.

[Ciderfeks]

Ok good, thats one less thing to worry about then!

[Gordonjcp]

Be really careful around the thin traces going to chip pins, particularly if you need to remove something - it's really easy to damage the through-hole plating that connects tracks on the top and bottom of the board.  Hope you've got a steady hand and a good temperature-controlled iron ;-)

[Ciderfeks]

A steady hand and a reasonable amount of patience, yes. A decent iron is on the Christmas list! Actually, as someone who works with this gear regularly, if not every day, is there a particular brand or model of iron that you'd recommend? I'm looking for something to do fairly standard stuff, making up simple circuits and circuit bending duties with an eye on the budget.

[Gordonjcp]

The Aoyue temperature-controlled irons are actually pretty good, and use fairly ordinary tips and elements so they're easy to get spares for.  I'm planning on getting myself one so I don't have to keep borrowing one of the ridiculously high-end Wellers from work.