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Updated: Mar 21

Some months ago I picked up an EMU SYSTEMS E64. This was model two out of the first pair of samplers released in the Emulator IV range. Every release had two models, a flagship with many expansion ports, and a version with less expansion capability (the E64)

What interested me most about the E64 was the amount of modulation capability that these machines have. They are extremely well featured in this area. Also, I really like the sound of the E64. It is warm and large without being overly coloured. The Ultra models have a cleaner sound. This is largely due to the more efficient DAC (digital to analogue converter) used in the ultra models.

This E64 was in nice visual condition, though it needed some work to make it more useful and useable.

E64 partially dismantled

Upgrade OS (two part process)

Replace Tact switches (these were failing, double triggering and non-triggering)

Replace encoder (failing, inaccurate value/turns presented to OS.

Replace LCD screen (this was actually ok, however during the other upgrades, it became unstable and needed replacing anyway)

Fan upgrade (original fan is small and very noisy)

Remove floppy Drive and replace with SCSI2SD drive. (Emulates 7 SCSI hard drives on an SD card)

Replace Power Switch

PSU recap and recalibration

I set about upgrading the OS via floppy from 2.0 to 3.0b. I learned a lot about floppy disks and drives during this period!

I used a virtual windows machine, a USB floppy drive and some 3rd party software to copy the .img file to the disk. This was fairly easy, though it took a while to achieve. As this version of EOS is 1.44mb standard formatting, a USB floppy drive will work to transfer the file although finding the right software to perform the transfer is more difficult. Rawwrite should work in most cases.

EMU ROM for the early models was a max size of 1mb. All EOS versions after and including 4.10 are 2mb. In order to run these (I wanted to have the bit reduction option in software) you need to replace the ROM card.

When I was updating the EOS I contacted a German engineer who has reverse engineered the OS ROM for the E64. He sells 2mb ROM sticks ready to go, with EOS 4.6.2 pre-installed. This is a hobby for him, not a full time operation. (I don't have contact details for him, I'm sorry)

Eventually the new ROM arrived on the 2mb stick and I was able to install it without issue:

EOS 4.6.2 on 2mb ROM

The fan mod involved a new large fan, removal of the old fan, and installing the new one against the power supply cover, depressurizing the case and ejecting the hot air from the rear. I eventually found a cheap enough fan (I have had so many ewaste fans it was difficult to spend money on this part!). The fan was a lovely garish red, and looks great inside the case! The fan takes 7v power by connecting 5v + 12v together (instead of 5 or 12 +GND)

Super bling fan installed

Tact switch replacement was tricky, although a simple task. The tacts have a very long plunger and there is zero margin for error: the tacts must sit absolutely flush with the PCB. Any tiny deviation from totally level means that the switch is difficult to trigger when installed into the case. Especially around the numeric keypad where many buttons reside together.

I was happy I ordered spares for this because I needed them! I had to cut a couple off and start again. It took a long time to desolder and resolder all these switches on the double sided board, even using a desolder station.


Tact switches removed

SCSI2SD V6. I had a friend print me a bracket for this, so it could be installed in the place of the old floppy drive. Only white thread was available to print. I thought this could look great against the mostly black of the sampler, so I was happy with that. I sanded the front panel down with wet/dry paper, it is as smooth as glass. It does look the business installed. And a bonus: the yellow activity LED on the SCSI drive shines through the white plastic!

Thingverse printed bracket shining yellow with activity

The Emulator IVs will only boot normally if a floppy drive is connected. After removing the FDD, a jumper must be placed on two floppy bus pins. The jumper appears to be a connected FDD to the system. The jumper sits on the opposite end of the bus pins in ultra and classic models! Mine took a long time to boot, so I swapped the position of the jumper, then it booted normally:

Jumper placement E64

The power switch must have taken a knock at some point; the cables just fell off during work on the PSU. Happily I'd just bought a load of switches, and an exact spare was found amongst the job lot! I was able to continue work immediately instead of having to spend ages finding and ordering a new one.

Power switch mid install

PSU recap and calibration. After removing the old capacitors (one which was about to burst) the new ones were installed, and the trimpot adjusted to give the correct voltages at the output.

emulator psu with new capacitors
PSU Recapped

Screen replacement. I had some help choosing the screen and tips for installing it so that contrast would be adjustable in software. One of the tips did not work well with this screen though, the backlight LED was temporarily disabled! After about half an hour it came back to light, though, I think it's a bit dimmer than it should be. Anyway it looks amazing with the new screen, and contrast is adjustable on the sampler screen: thanks for your help Ray!

Install a trimpot in line with pin 4. Do not connect pin 1 to GND!

Screen PN: ERM24064SBS-1

Replacing the encoder was easy. Simple desoldering and resoldering of the new part. The metal surround (the tubular part with the bearings) unscrews easily from the old encoder and screws onto the shaft of the new one. The encoder board in my E64 had been modified with some 1uf SMT capacitors. I was able to work around these to leave them in place. They add smoothing to the response of the encoder pulse outputs = smoother more accurate readings from the EOS when turning the encoder.

So, now the E64 is completely refurbished and has a modern storage SD card system. I will probably get some more RAM in the future. At the moment, the E64 is in storage (sadness many) I would like to start using it - later days!

I plan to make a midi controller using a Doepfer Pocket electronics midi utility, so I can control the modulation parameters. I could use some faderbox, that would be less fun though.

If this post has helped you work on your EMU, please consider a donation - ta boss

Here she is finished up at night to better display the screen:

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