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.

Amiga Video PCB

I decided it was time to make some kind of replacement for the bulky Amiga 500 RF modulator. This little thing has a nice composite output and a S-VIDEO output for great video quality. Unfortunately, the female DB-23 connectors are hard to find, so I wont be making many of these.


I figured the AD724 would do nicely.

A little about the AD724:

The AD724 is a low cost RGB to NTSC/PAL Encoder that converts red, green and blue color component signals into their corresponding luminance (baseband amplitude) and chrominance (subcarrier amplitude and phase) signals in accordance with either NTSC or PAL standards. These two outputs are also combined to provide composite video output. All three outputs can simultaneously drive 75 Ω, reverse-terminated cables. All logical inputs are TTL, 3V and 5V CMOS compatible.

I do have several PCBs and parts available, but since the DB-23 connectors are not easily available, I will only post the PCB for sale.

Parts list: (position, value, size)

C1 100n 0805
C2 100n 0805
C3 100n 0805
C4 220u
C5 220u
C6 220u
C7 15p 0805*
C8 100n 0805
C9 10u
C10 2-22pF*
Q1 X-tal 4.433619 MHz for PAL, 3.579545MHz for NTSC
R1 75 0805
R2 75 0805
R3 75 0805
R4 75 0805
R5 75 0805
R6 75 0805
U1 AD724 SOIC16W
DSUB 23 Female

*Only one of these to be used, eighter one 15pF at C7, or one adjustable one at C10

The PCB is default PAL (pin 1 low), but you can pull pin 1 on the AD724 high to select NTSC. (PAL is low and NTSC is high)
This PCB has not been tested in NTSC mode.

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

Gotek USB floppy emulator


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
E-mu ESI-32
General Music (GEM) Synthesizers
Sequential Circuits Prophet 3000
Tandy Color Computer

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 Amiga 500 Rev.5 Kickstart upgrade.

A friend came over with his beloved Amiga 500 and wanted me to help him get Kickstart v 3.1 installed. It turned out to be a rev.5 motherboard.

The kickstart is basically a part of the Amigas OS, and the software is stored on ROM chips. The Amiga 500 has only one ROM, but other models might have two. You replace it by taking out the original and replace it with a new one. I just programmed a 27c400 EPROM for this.  (See my other post about my Kickstart adapter and how to use it.) A legal license can be bought at Hyperion. After programming the EPROM, its usually only a matter of swapping chips, but not on the older A500s.
The rev5 and older motherboards has a small signal routing bug in it, that the user usually never get any problems with unless they want to upgrade the Kickstart. If you look at the schematics from Commodore, you will notice they actually put “oops” in there, and thats why we used to call it “the oops bug”

You can rectify this bug by bending up pin 31 on the new ROM and connect a wire from pin 1 and pin 31 on the ROM. It is important that the pin 31 does not touch the socket. Next you have to solder yet another wire to keep the EPROM in 16-bit mode. This time its from pin 21 (VCC) to pin 31. As usual, I hate to hack OTHER peoples hardware like this, so I decided it was time to finally make a PCB for this bug. (my own A500 had to endure me just hacking up a socket for this bugfix. Shame on me.)


This time I wanted to try using RED PCBs. Not bad at all. As you might have noticed there are more on this adapter board than only a socket. The old rev5 PCBs also has had a history of throwing out some random “guru meditation” errors and even some times they even refused to boot after upgrading the ROM. This was also true on mine. But what exactly was going on?

I decided to compare the schematics on a rev6 with the schematics on a rev5. I found that Commodore had added resistor nets on the data lines between the ROM socket and the CPU on the later revisions. So I decided to REALLY destroy the old socket solution on my own machine and added some pullups to the datalines. All the problems suddenly was gone. So I decided to put the “missing” pullups on the socket. After hours of testing  my friends and my own Amigas, both ran very stable.


These are the parts needed. The correct resistor nets was really hard and expensive to source. I made a star on the PCB to match the “dot” printed on the resistor net so I wont forget the orientation.  The dot and star indicates the VCC pin, by the way. I printed SOCKET and Chip to remember where to put the “turned” pins (socket) and where to put the ROM (chip). In hindsight it would probably be better if I used the words Pins and Socket instead…

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


I decided to make a fresh batch of my old Retro4fun PCBs. This time in RED color. Its basically just an adaptor that plugs into the Parallel Printer port of any Amiga and gives you 2 extra joystick ports, for a total of 4 joystick ports.


Some of the Amiga games compatible with 4 player:

Air Taxi
Ballistic Diplomacy
Base Jumpers
Blast Squad
Blitz Bombers
Blitz Tennis
Blob 1.1
BOMB 1.21
Bruce Lee
Bug Bomber
Burn Out
Carnage (Zeppelin Games)
Blooded Murder
Crossfire II
Dogfight Simulator 1.5
Dynamite Warriors 2.0
Flyin’ High
Gauntlet 2
Great Courts 2
Hired Guns
Hot Rod
International Soccer (MicroDeal)
James Bond
Kick Off 2
KnockOut 2
Laser Bikes
Manchester United Europe
Master Blaster
Max Rally
Monsters of Terror
Moochies, The
Over The Net
Rally Cross Challenge
Smash T.V.
Space Power
Space Taxi 3
Speed (Demo)
Street Racer
Super Gem’z
Super Skidmarks
Super Tennis Champs
Tank Attack
Tank Wars
The Race
Tie Break
Tip Off
Turbo Hockey 2
TV Sports Basketball
Ultimate Super Skidmarks
Wheelchair Gladiators
Worm Wars
Wormsigns (Preview)
Xtreme Racing

This Adapter is compatible with the PPjoy freeware program. PPjoy let you use compatible adapters on a regular PC so you can get joystick ports to use with your favourite Amiga, C64 and other emulators like Sega etc. It let you set up your printer port as joystick ports.

The list is taken from a list posted on Aminet.

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

DIY Amiga 500 memorycard

Its always fun to make your own things. This time I decided to make some memorycards for me and a couple of friends. I now have 2 A500 without trapdoor memorycards, because they had battery damage. So instead of buying another old more or less battery acid damaged unstable card, why not make brand new PCBs and solder them for yourself?


For a regular 512k trapdoor memorycard, all you need is:

  • 1x 100nF decoupling capasitor
  • 1x SOJ42 ram chip.
  • 1x 2.54mm 80 pin connector.
  • 1x PCB

This particular PCB has been designed to be quite versatile. Besides of being used as a replacement for a simple 512k trapdoor memorycard, for A500 and A500 +, it also can be extended by simply adding one extra capacitor and one extra SOJ42 ram chip, to become a memorycard also for the Amiga 500+, giving the 500+ a total of 2MB chip ram. A few jumpers needs to be connected to hook up the RAS + CAS signals to the other memory bank and to the motherboard connector for this, since the PCB is set as default for being a 512k ram card.

But it does not stop there. The card also can be fitted with a few more parts to also have a working RTC, or real time clock with a modern battery.

On newer revision A500 you can also add a Gary Adapter for upgrading a regular A500 to a total of 2 MB RAM! This however, require some hacking on the Amiga mainboard. When ordering the PCBs I ordered the Gary adapters, but I dont think I will ever use any of them, but they had to be made, right?


The Amiga 500 + Has its own RTC. (real Time Clock) on the mainboard. This is to remember time and date. However, the regular A500 usually had this embedded on the memory expansion board. All the pads for this is embedded in the PCB, but it is totally optional to add the components. This is what you would need to add this feature.

  • Parts list for RTC:
  • U5 or U6: RTC62421/RTC72421/RTC62423/RTC72423
  • R7: 47K-100K 0805 resistor
  • C12: 100nF 0805 capacitor
  • C13 or C19: >=2.2μF >=10V 0805 or 1206 tantalum
  • R1, R2, R3: 10K 0805 resistor
  • R4, R5: 220-470 0805 resistor
  • D1: BAT721C or BAT54C diode
  • Battery Holder

The memorycard with RTC:


I put a sticker on it after it was tested to remind myself that it’s tested and working.

This is what I do when I build one of these:

I start with soldering the ram chip to U1 using solder paste and a heat gun. I use my multimeter afterwards to verify that all the pins are connected and not shorted. Then I solder the 100nF decoupling capasitor to C1 using solder paste and heat gun. If I want to add the RTC feature, I do those parts before the connector, since there are plastic parts on it. The connector needs to be cut. It is important to use something sharp. I use my sharpest sidecutter for this. I cut on top of the first pin not in use. This is because the connector tend to break into small parts at the cutting point when cutting this way. If I cut between the last pin and the next, It tends to damage the plastic holding the last pins. Cutting on top the next pins avoids this. I will be discarding the rest of the connector anyways. Im sure using a professional saw or Dremel would cut this much nicer, but I dont have one of those handy.

BOM and instructions:

For 512K:
For 512K:* 1 x 1Mx16bit SOJ42 DRAM
* 1 x 56pin (2×28) 2.54mm double row right-angle header (or 2x40pin and cut it)

For A500+ 1MB:
* one more DRAM

For Gary Adapter:
* more DRAMs (any number you want)
* 1 x 74F139 or 74HCT139 (surface mount)
* 3 x 74F00 (surface mount)
* 1 x 74F74 (surface mount)
* 3 x 3-pin jumper headers
* 3 x jumpers
* 2 x 24-pin DIP sockets
* 2 x round pin strips
* Wires and some 2 and 3-pin 2.54mm connectors of your choice

Jumper changes from default 512k:
1MB Chip (A500+):
XRAM: Open
RASU2 to RAS0 closed


512k Chip + 1.0/1.5 Slow with GARY adapter:
XCAS: all open.

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


Amiga External Floppy controller

This project was initially made for the purpose of using an internal Amiga floppy as a secondary drive for copying disks. But later, I added jumpers so that PC floppies can be used too, since these are easy to find. I later also found it useful to have a jumper selector for selecting DF1:, DF2: and DF3:


It turns out that the DB-23 connector that goes in one end of this adapter has gone out of production several years ago. There are still connectors available, but at a price that is not realistic and it smells like speculation. After experimenting a bit, I found that using a regular DB-25 connector work just as good. These are still in production, and to my surprise they work great. Better than great. All you have to do is to snip off the extra pins with a sidecutter.

I was afraid they would be awkward to fit, and easy to put in wrong, but instead they slip right on without any issue everytime. At this point Im convinced its a real waste of money to buy DB-23s when the DB-25 work so great. I have actually made a couple of these to people insisting to have the correct connector, but I had to up the price considerably to recoup the extra cost.


The PCB was made in a way that you can eighter solder in a floppy connector, or just use pin headers like in the first picture. The Floppy connector would ensure that it is not possible to put the cable the wrong way around. Look at the image for default setting when used with a Amiga floppy drive or a Gotek with hacked firmware.

Jumper settings:


Old version.

This is the latest version PCB I made. I added a Ready jumper so that PC floppies without ready (rdy) jumper can be used too.

DS0/DS1 jumper.
The jumper to the left in the picture is drive select. I made this because many PC floppies has no jumper for drive select. (DS0 or DS1) on a PC, floppies was usually hardwire as DS1, and then they used a twist in the end of the IDC cable to swap the pins back to DS0 for the computer to read it as A: if you connected a second floppy drive to the IDC cable, there was no twist on the connector and the computer would read it with the hardwired setting DS1, and assign it as B: You can safely try both.

Amiga/PC jumper
The Amiga/PC jumper is to tell the adapter if you connected a PC compatible floppy, or a Amiga floppy. Its what forces a PC floppy to be compatible with your Amiga. Default would be Amiga. Set to PC for PC floppy.

Ready jumper (New on later revisions)
The Ready jumper is to tell the adapter if you connected a PC compatible floppy, or a Amiga floppy. Its what forces a PC floppy to be compatible with your Amiga by forcing the ready setting to match the Amiga requirement. Default would be Amiga. Set to PC for PC floppy.

DF1 to DF3 jumper
The last one, is the jumper set that has 6 pins. It selects between DF1:, DF2: and DF3:. Default would be DF1. I made this because sometimes you have already 2 floppies connected. My Amiga 2000 had 2 floppies inside, so to use this external adapter on that machine, I had to be able to wire this as DF2: to avoid problems. DF3: is when you have 3 connected drives and this is number 4.

Fortunately, this adapter works great with the Gotek, which is one of the most popular addon in Amigas these days, due to its availability, and that it is so easy to use.

The old floppydisks are getting harder to find, and the drives are getting old and worn out. My personal preference is to have both. I still like to have original disks, but having the .adf files on a SD-card is so convenient and tidy.


C1 100nF Decoupling Capacitor
C2 100nF Decoupling Capacitor
DB-25 Connector to be modified to DB-23
IDC FDD Connector
4X Jumpers
R1 2.2k resistor
R2 2.2k resistor
R3 2.2k resistor
U1 74LS74N DIL14
U2 74LS38N DIL14
Power Cable with connector to Floppy drive


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

PS/2 to Amiga/Atari adapter

I really wanted a PS/2 to Amiga adapter, so I ended up making this PCB in Eagle CAD based on information freely available on the Internet. I ended up making one that can use both USB and PS/2 connector, and the option to change between Amiga and Atari ST mode with jumpers. It also works on Commodore 64 in certain applications.


This thing work on a lot of USB mouses, but not all. It requires the mouse have the PS/2 protocol to work. A lot of mouses with PS/2 plug also included a PS/2 to USB adapter. Thats a good indicator to see if it works.


This is plug and play. No need to install drivers.



It does fit the Atari too. I had to make it super slim, because of the way they designed the case.

This is how I assemble these.


From the left, you can see I start with the Microchip. Then I move on to solder the DB-9 connector. Third, I do the capacitor, then the jumper pins. Lastly, I decide wether to install a USB or PS/2 socket. I do it like this because it is easier to install the smallest components first, moving over to the bigger last.

The modes:


This image shows the two different modes. To the Left its set to Amiga mode, and to the right its set to Atari mode.

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

CDTV Joyport Adapter

After finally getting hold of a Commodore CDTV, first thing I noticed was that it did not have the usual DB-9 connectors that the other Commodore models have. The machine did have a mouse port, but it turns out it is not a standard one, and I did not get one with the machine, so I had to find another solution for using mouse and joystick, because the remote controller was a weak subtitute for a real joystick and mouse in my opinion. I also wanted to use a modern optical mouse together with my already made PS/2 to Amiga adapter.

Looking at the CDTV service manual, at page 17 there is a chip marked 252609-02 at location U75. Turns out it has all the pins for both the joystick port and mouse port. My first plan was to solder wires directly from the chip and onto 9-pin connectors with solder cups. But then I decided to draw a PCB in Eagle CAD instead.


I opened my CDTV and it turns out there are a few components blocking a big PCB, plus that the distance between the mainboard and the lid is quite narrow. So I had to make the size and placement of the connector as shown above. The idea was to use the same principle they use when they make adapters for EEPROM programmers. There is a socket for the original chip, and then there is legs on the underside to insert into the socket on the motherboard. Now we can just route some traces from the pins on the chip that has the needed signals for left, right, up, down, fire and ground without soldering on the chip itself.

I found out that on Ebay they still had IDC DB9 connectors that was perfect for his project. Turns out 20 pins IDC sockets were much cheaper than 18 pin, so I decided to design the board for a 20 pin connector, but to only connect 18 pins (2pcs 9pin connectors) So the board consist of these parts:

1PCB, 1pcs 20pin IDC, 2pcs IDC d-sub 9 pin male, Turned pin header for inserting into the U75 socket, 1pc 40pin DIP socket for the 252609-02 chip, Double 2.54mm header for the 20pin IDC, 45-50cm IDC cable.

It turned out that the distance between the lid and the PCB was so narrow, that I had to use angled pin headers for the 20pin IDC connector. Below, in the picture to the right, you can see that the connector take a lot of room, so I had to desolder the pin header and replace it with one with angled pins as shown on the left picture.


Because the CDTV remote uses the pins from Joystick port 1, there might be a problem using both at the same time with a mouse or joystick. The solution is to try and press RIGHT on the CDTV remote once the CDTV is switched on with your program or game loaded. If this wont work, you can disable the CDTV remote like this: remove U75, bend up pins 6, 7, 8, and 9, and replace it back in the adaptor’s socket. I might make a jumper or DIP switch solution on my next revision of the PCB, so that those pins can be disabled without disturbing the chip. They will fit perfectly on the side of the 20 pin IDC connector. If you look closely on the picture, you will se that the pins are bent to the side. I dont recommend anyone to bend them several times. A different approach to solve this would be to cut the traces on the adapter instead, to avoid bending the pins. The traces to cut would be the ones leading from the socket on top of the adapter that lead out from the 4 pins I bent in the picture.


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

Home made Amiga Boot Selector

Have you ever wanted to use a Gotek on your Amiga without having to make changes to the Amiga itself? I think too many Amigas are being “mutilated” to fit a Gotek these days. Instead you could use the internals of an external floppy, and change out the floppy with the Gotek. problem is, many games require to boot from DF0: This is where this selector is being handy. Models with SMD CIA, like A600 and A1200 can not use this device. Since they have internal HDD interface, they can just use WHDload games instead.

Background: The CIA chip (Complex Interface Adapter) inside the Amiga is used for communication like the Serial Port and the Parallel Port. But thats not all it does.

The Amiga Computer uses the CIA chip to determine the floppy drive ID (DF0: or DF1:) This is done by pulling select lines low. There are several select lines, D0, D1, D2, D3. If you for instance swap pin 13 and pin 14 on the chip marked Even CIA (U8) on the Amiga 500, you will make DF1: to be DF0: and vice versa. Normally, the internal drive is DF0: and any external drives is DF1:, DF2: and so on. But what if we want the external drive to be DF0:? That can be done by simply swapping pin 13 and pin 14 on the CIA chip. This is where this switcher comes in. I browsed the net for ready made solutions, but the ones  I found, was mostly 2 sockets soldered together and a switch and usually sold out,  so I decided to make my own switcher, but with a PCB. The design I chose uses a flip flop logic chip instead of just a normal switch to swap the pins. I would hate to damage my CIA with just a manual switch. With this selector, the CIA is a lot safer.

DSCF9072.JPGDSCF9067I decided to make one with normal dual wipe socket and normal pins, (right) and one with “turned pins” (round pins) The idea is to remove the CIA from its socket, and put this there instead of the chip, and then put the CIA in this socket.  You can use this by simply leaving a jumper in or out. One can easily use a switch where the jumper resides to change the setting without opening the computer. Personally, I wont be changing the switch often, so Ill go with a jumper, since I dont want to make a hole for the switch. These days I mostly start my games from a Gotek, so I dont need the internal drive for other than copying disks. Since many games require boot from DF0:, its good to be able to boot from an external Gotek and make it DF0: Now I can leave my Amiga intact instead of hacking it up to install a Gotek internally. With this, the internal disk is now DF1: and the Gotek is DF0:

You can use this image to identify where to put the parts. The cap is hidden under the socket in the left, and the 330 resistor (marked 331) goes to the left, and the 10k resistor (marked 103) goes to the right in this image.


I sent my gerber files to a PCB factory, original design by Jussi Kilpelainen.

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