Enhanced Gotek: The Brutek!

Brutek PCB imageFor a long time, I have worked on recreating the Gotek and in the process adding extra features and several bugfixes from the original Gotek. v1.0 was just a prototype replica of the original Gotek with some of the pinheaders moved for easier flashing. I just wanted to see if I could get one to work. Summer 2019, I gifted v1.0 to everyone that showed up to a local Amiga game night and requested they would perform extensive testing. They all still work, but they had some design flaws like the screw holes was not at the correct location, regulator needed more cooling area, the PCB was about 4mm too short, the tactile switches was placed too close. So I modified my “Bruktmoped” Amiga 500 internal frame to fit the replica with wrong screwhole placement, so my testers could place the prototype internally to their A500 machines.
v1.1 had these issues rectified and I decided to implement the mods that the awesome FlashFloppy firmware supports, plus some things I wanted changed myself, including more SMT friendly layout compared to v1.0.

These are the things I have changed/added:

  • Added a power LED
  • Removed R10
  • Moved and added pinholes for more jumperfriendly layout.
  • Replaced the cheap electrolytics with SMD capacitors. (from v1.2 and up)
  • Used genuine ARM® Cortex®-M3 processor. (instead of those fake ones often found on Goteks from China.
  • Replaced STM32 output buffer with more suitable chip for that application. (From 74HC04 to 74HCT04)
  • Added 3pcs SMD LEDs (from v1.2 and up)
  • Replaced R13 with higher value resistor for more stable programming. (From v1.2 and up)
  • Added pulldown resistor to Boot1.
  • Made holes for optional header to pullup Boot1 with a jumper.
  • Board identifier set to support Enhanced Gotek mode with FlashFloppy.
  • Added support for the upcoming FlashFloppy feature “Second drive support” (PA3 pulled up.)
  • Added jumper friendly pinholes for the upcoming FlashFloppy feature “Second drive support”
  • Added LED for the upcoming FlashFloppy feature “Second drive support”
  • Added motor ON feature. (For future FlashFloppy features)
  • Holes to connect Rotary encoder, with extra pin for drive eject/insert
  • Onboard speaker holes for passive buzzer. (for drive sound emulation)
  • Transistor circuit so even 5V active buzzer or magnetic speaker can be used, and higher volume is possible.
  • Added pullups to SCL and SDA so there is no need for modification when using a two- or four-row LCD with I2C backpack board
    instead of the usual 7-segment original Gotek type display, or a OLED screen. (From v1.0 and up)
  • Added pullups to several floating datalines.
  • Moved and changed Crystal to high accuracy SMD version. (from v1.2 and up)
  • Made fiducials for factory SMT option.
  • Changed values on several passives.
  • Did a google for other enhanced Goteks, and borrowed some great component placement ideas from other
    PCB designers smarter than me! (from v1.2 and up)
  • Correct pullups for SCL and SDA so the 4.7k resistors mentioned in flashfloppy OSD guide is already in place.

Gotek USB floppy emulator

gotek

This is a great solution for replacing a old floppy drive. It works like this:
The gotek has built in 999 locations where you can place a floppydisk image. This image contains the contents of one floppy disk. These pre made images are usually easy to find on the Internet, but you can easily make a image of a real floppy disk you own.

All you have to do to use the gotek, is to put the images on a USB pen drive, and assign each disk a number. The gotek has 2 buttons in the front, where you can select the disks. One for up and one for down. Lets say you want to boot from a game or program that you assigned to slot 5. All you have to do, is to press the buttons untill the display shows 005, and the disk will load. You can press the buttons back and forth to select images, and your computer will behave as if you inserted that floppy disk. Its a great way to get rid of those old worn out floppy disks, and great to save space.

Available upgrades:
-Speaker that emulates floppy loading sounds!
-OLED screen that replaces the original display, so that the name of the disk is shown in letters instead of numbers, meaning you dont have to keep track of where you assigned your images.

The drive itself: The drive comes new with a really bad firmware that hardly can be used to anything. So you need to circomvent the protection of the drive, and flash it with a new firmware. I use FlashFloppy. If I sell one of these, they are already flashed with FlashFloppy.

Once the protection has been broken, future updates is as easy as to put the updated firmware in the root of the USB stick, and power on the gotek with both buttons in the front pressed in at once. The drive will now update itself. Be careful not to disconnect the power during this process.

This drive can be connected to any computer that has the same Shugart 34-pin header, such as

Acorn Archimedes
Acorn BBC Micro
Akai Synthesizers
Amstrad CPC
Atari ST
Commodore Amiga
DEC
Dragon
E-mu ESI-32
Ensoniq
General Music (GEM) Synthesizers
IBM PC
Korg
Memotech
MSX
NEC PC-98
Roland
Sequential Circuits Prophet 3000
Spectrum
Tandy Color Computer
TI-99/4A
UKNC, DVK

The FlashFloppy firmware ensures that they all work.

WARNING! If you connect the power cable in the back wrong, IT WILL KILL THE DRIVE.

Some computers require different jumper settings on the drive. Usually all you have to do, is to move jumper S1 to S0. If that dont work, try these options:

Jumper at S1 only
Jumpers at JC and S0
Jumpers at JC and S1

These files must reside in the root of the USB stick for it to work

This project with PCB and parts can be purchased on ebay:  https://www.ebay.com/usr/kirsti_73
or from Sellmyretro.com

The Atari SF314 Floppy

Today I decided to look at the external floppy drive that I got from a bundle of so called working retro stuff.

The floppy had this problem, it would just keep spinning whenever I put a floppy disk inside it. So I decided to have a go at it, so I opened it up, gave it a full cleanup and decided to just change the capacitors on it, since this is usually the fix on retro floppy drives like these. It turned out that this drive did not have any SMD electrolytics. Instead it had 3pcs 22uF @ 16v, and 1pcs 1uF @ 50v shown below

DSCF8829.JPG

I decided to pop them out, Insert new ones, and presto! The disk drive worked again. I made sure to clean the stepper motor mechanism while in there and added a small amount of oil on all moving parts.

Usually these kind of caps dont need to be changed, but in this case one of them did. Because I often repair old stuff, I decided to buy a quality instrument to diagnose caps. My choice was the PEAK atlas ESR+ model ESR70 and it is just a dream to work with, but its kinda expensive for the hobbyist like me. But the Atlas did its job and found the culprit. Since one of the caps had way too high ESR, I figured I found the one causing problems.

Of course, when you buy used stuff that dont work, it has often previously been opened by someone. This was also true when it comes to this device. It was aparent by the 3 lacking screws in the bottom, but fortunately, I have a nice stock of replacement screws, so now it is both clean inside and out, and it has all the screws again. …and new caps. I tried it on my Atari 520 ST. It works great, and is also surprisingly quiet. Now to play some Atari games!