Faulty Drumulator

[gertie]

Try putting it in SEGMENT mode, hold Erase and tap the Cassette key. When the display flashes "PooF" hit Enter and the sequencer should work (memory cleared)

dont know if this will help you as this is to reset it when you get the bAd message....ie memory backup battery inside is dead and the RAM is scrambled

[ambivalent]

None of the LEDs light up so I can't tell if I'm in segment mode. However, I've followed this procedure, then hit the segment button and tried it again just to be sure. Still nothing. Even if the LED display wasn't working would I still hear a beep to confirm the reset?

[ambivalent]

If the memory roms can be take away, shut the machine down, take them away, and restart the machine without them.

Hi Dr C

Just about to attempt this. Just to clarify, do I need to remove the memory chips around the CPU (13K, 15K, and the OS EPROM 12K) or the sound memories (1E, 3E, 4E, 5E)?

Thanks

[dr.c]

Take off the SUSTEM Eprom, start the machine, leave it for 5 dseconds, stop it, shut it down.
Refit the Eprom and see what it does.

The reason of this, because some are going to think I am nuts :
At startup, the sytem goes to see what is in your static ram. If the static ram sends the processor to hell, it will go and stay there.
Now, if the processor is "crazy" (without a system), its gonna scramble everything in the static ram, in a way, erase the bad ordezrs and then, since the processor is not going to understand, its gonna stop and send a "bad" message.
Then you will have to reset.
If this doesn't work, take the sound roms away and restart your machine, see what it does.
The reason : if a sound rom is bad, it will pollute the data or adress bus.

[ambivalent]

I just got round to doing this. Removed the system ROM, powered up for 5 seconds then switched the unit off and refitted the ROM. No improvement. Tried the same but removing the sound ROMs. No improvement. Tried with both system ROM and sound ROMs removed. Still no improvement.

[dr.c]

Now you need a scope and good knowledge in electronics. Sorry...

[ambivalent]

Well, I'll have to admit defeat. I think I'll be putting it in the classifieds section. Hopefully someone can get it up and running but it's cosmetically immaculate so at the very least it's a great donor for spare parts.

[dr.c]

where are you located ?

[ambivalent]

I'm in the UK.

[rtech]

hey gs3333,

  Did you ever get the Drumulator fixed? I got an Drumulator a while back from a friend and was trying to bring it back to life, the Sequencer does not work. When you power it up it shows the "bad" message. I was reading the Repair Manual and discovered the the capacitor next to the battery was open, so I replaced it but I am still receiving the bad message and can not record sequences. There are occasions when I power it up I can hear all the drums sound play rapidly on their own.

  Dr. C or any one know where I can get the Diagnostic ROM so that I can test it?  Or any suggestions on how to bring it back to a fully working Drumulator.

[rtech]

Thanks for all the help, I finally got it working. For any one having the same issues check the traces on the HM6116 Static Memory Chips. These traces are prone to corrode and open. I soldered a small jumper cable and everything is working now.

rtech

[valvusmusicus]

Hi All
I have one that wont power up too!
Rplaced all the regulators as a matter of course-and the CA3086 transistor array-all the tants and PSU electrolytics. All rails are up and running-but the -ve and =ve 15v get a little hot-any ideas what might de drawing too much, where to start-no display-nada

many thanks