Floppy drive disk detection repair - as not expected

A surprisingly simple repair to a microscopic, but essential problem with an Amiga 1200's floppy drive. 

This drive didn't work reliably, and at some point failed completely, not detecting disk media anymore. Only with a little bit of extra pushing on the disk, it would click and start reading, but immediately stop when released. A more thorough inspection was required.

The mechanism didn't feel very snappy when inserting the disk, so some dirt, lack of lubrication, or worn out spring was the first guess. But it turned out everything moves nicely. Next, the "disk inserted" switch was inspected, drenched in isopropyl alcohol, tested, even resoldered, it was fine, but the drive still didn't work. Suspecting a worn out disk "sledge", that prevents the switch from getting fully pressed down, a little bending was applied to some of the metal side pieces - with no success.

Amiga 1200 floppy drive without cover plate - the slightest touch would make it work.

Basically everything about this floppy drive was fine, only it still required some pressure on the top of the disk. With more inspection, cleaning, etc. it became a little bizarre: Only minimum pressure was required, the weight of a finger, creating microscopic movement.

The solution was found when looking at another, very similar floppy drive: The disk guides at the drive's front aren't supposed to be tilted to the inside. On the other drive, they're perfectly horizontal, parallel to the top edge.

That was a little unexpected. Amiga computers are old, this Amiga 1200's drive had the guides slightly bent, tilted towards the inside, for decades, and worked fine. But it makes sense, bent guides could prevent the disk "sledge" from fully touching down on the drive's base plate, thus not triggering the disk detection signal properly.

Bending the guides back to a (near) perfect horizontal position indeed fixed the problem.

Open drive, and disk "sledge" (top part), with straightened guides at the front.
A similar drive, used for comparison, on the left.

The lesson learned is that these guides wear out, and they were worn out on this drive. Who would've thought. They seem to hang in the air when no disk is inserted, and they're hard to see when a disk is in the drive. If you've never consciously looked at them, or even if you have, you assume they're built this way. And you probably don't expect that when they're bent down another 10th of a millimeter, they prevent the drive from working. 

It might have worked for decades, and it wasn't even expected to be wrong, but still: If it's bent, it's probably broken!

Missing screw on the backside - that's acceptable.

While at it, the casing of the drive was checked, so the sledge has no unnecessary action. This drive is missing a screw on the backside, but with a little straightening (bending... ;-) ) of the top piece, and making sure its sides fully snap into place on the drive's body, a tight fit can still be achieved.

Floppy drive immediately detects floppy disk again. Very good.

That was a very unexpectedly simple repair. The drive disassembly was unnecessary, it probably could've been done even without opening the Amiga computer. And it even was totally analog. Awesome.

AMIGA alive 04: Floppy drive repair (write-protection switch) (Video)

A little repair job on a faulty floppy disk drive.

https://www.youtube.com/watch?v=p9eVTkj3hlU

The awesomeness: Amiga hardware news - galore! (2/2)

Even more pure awesomeness. The Amiga community is without a doubt the most active and knowledgeable in the retro scene.

Paul Rezendes' Amiga 4000 replica mainboard

We've already reported about this project - and, yeah, it's done, thanks to Paul and the community!

The GoFundMe campaign has reached and even exceeded the amount of money required, and Paul Rezendes was pretty quick at getting the first boards produced and tested. By now the files created have been released to the public, and you can even order a board from Paul.

https://github.com/Acill/A4000RevB/blob/master/Images/20180804_091312.jpg?raw=true

Another fantastic addition to the range of newly available Amiga parts. Now there's no excuse not to resurrect your battery-leakage-damaged Amiga 4000 from the attic!

The fundraising campaign can still be found at:
https://www.gofundme.com/amiga-4000-replica-with-schematics/

The files required to build your A4000 replica mainboard can be found at:
https://github.com/Acill/A4000RevB

Take a look at Paul's website for some pictures of these beauties, and order a board if you like:
http://www.acill.com

...and arananet's Amiga 4000 daughterboard!

With the Amiga 4000 replica mainboard done (see above), and John Hertell's A3660 Amiga 4000 CPU board done, you might be wondering "cool, but I still can't build my Amiga 4000 without a ..."

Daughterboard. Wonder no more.

Eduardo Luis Arana has published the files required to build a updated daughterboard. The ISA ports has been removed, and it now includes a 15KHz VGA display connector to use with a breakout / backplate bracket. And it has some nice fiery design on the backside.

https://github.com/arananet/A4000db/blob/master/img/1.png?raw=true

You can grab the files required build your new Amiga 4000 daughterboard from GitHub at:
https://github.com/arananet/A4000db

Amiga S-video board

The Amiga's video connectivity features, while being highly convenient about 25 years ago, have turned out to be somewhat problematic today, and every update to them is warmly received.

http://electronics.chroma.se/svideo2.jpg

This board connects the any Amiga's 23-pin display output, and has a composite video, an S-video, and a 15KHz VGA output connector. Picture quality is claimed to be higher than Amiga-built-in outputs, especially using the S-video output.

Here we have another little success story regarding teamwork among Amigans: this circuitry is the one being used in John Hertell's ReAmiga 1200 for video output - nice! (see part 1 of this article)

Go to this website for more information about the Chroma Amiga S-video board:
http://electronics.chroma.se/svideo.php

K1208 and A1200 SDE+ 8MB FastRAM, SPI (SD, Ethernet) boards for Amiga 1200

Derived from Stephen Leary's TF328 project by Kipper2k, and further developed by Solidcore and Mike Stirling, these are two similar expansion boards for the Amiga 1200.

The specifications read as follows:

• 4MB/8MB FastRAM jumper (4MB for PCMCIA support)
• microSD card slot, up to 4GB FAT95 (FAT/FAT32) formatted cards (SPI 8MHz)
• Ethernet ENC28J60 SPI module support (SPI 8MHz)
• Real-time clock
• 2800+ dhrystones on stock Amiga 1200 (14MHz 68EC020)

The situation with these boards is a bit unclear, no conclusive information about final development and availability could be found. It looks as if currently only the software for the cards (drivers and firmware) has been released to the public.

If you want to know more, check these links:http://eab.abime.net/showthread.php?p=1212721
http://www.amibay.com/showthread.php?100275-A1208-8MB-Fastmem-SPI-(SD-Ethernet)-Board-for-A1200
https://www.mike-stirling.com/2018/05/sd-card-and-ethernet-on-the-amiga-1200/
https://github.com/mikestir/k1208-drivers
https://github.com/mikestir/k1208-cpld

(If you can clarify about the situation please leave a comment, thanks!)

Inexpensive A500 hard disk interface

A nice little addition for your quick harddrive needs might be this straightforward Amiga 500 harddisk interface. It requires a floppy disk to boot from and has been successfully tested with Kickstart 1.3 and 2.0.

Now this one has a feature that cannot be praised highly enough:
As you can see in the picture below, it has two expansion port connectors, one after another - the front one is an adapter to standard 2.54mm pin grid connector, and the other one is the pin grid connector mounted to the PCB. As the author says in the README file: "[...] future expansions will be developed with pin headers as their main connector." Huge sigh of relief. Finally someone starts to get rid of proprietary, hard-to-obtain connectors, and replaces them with widely available, future-safe solutions. One small step for an expansion board, hopefully one giant leap for Amiga-kind.

https://github.com/AmigaPorts/a500hdd/blob/master/doc/nib.jpg?raw=true

As of now the latest commit to the GitHub repository happened just 11 days ago, so this is apparently under active development.

The projects website is located at:
https://github.com/AmigaPorts/a500hdd




BONUS HARDWARE:

GRETA FastRAM/microSD/ethernet expansion board for Amiga 500

A couple of years ago, Martin "endofexclusive" Åberg from Sweden created GRETA, a Xilinx Spartan FPGA-based expansion board for Amiga 500. It's build to add 8MB SRAM, a microSD slot, and 10/100MBit ethernet controller to the Amiga. The project files have last been updated on August 1st 2016, and hardware programming is still incomplete - currently only RAM expansion is supported.

GRETA seems to be some kind of forgotten gem among Amiga hardware expansions - the specifications look fantastic, it contains all of the features one would like to have on a single PCB. As it seems, there's only some programming required to make things work.

https://github.com/endofexclusive/greta/blob/master/doc/mounted_components2.jpg?raw=true

Wouldn't that be a nice project to pick up and give it some love?

Looking at the other amazing expansion boards that have come out in recent years, probably even an unexperienced programmer would be able to add ethernet and microSD mass storage support to the device, there's plenty of material out there to study and learn from.

If you're interested, go to GitHub, and start building your GRETA:https://github.com/endofexclusive/greta

You may find more information about GRETA in this forum thread on a1k.org:
http://www.a1k.org/forum/showthread.php?t=54707
(currently a1k.org doesn't accept new member registrations)

* * *

Thanks for reading!

Support Amiga hardware development!

Donate!

Buy stuff!

* * *

This part 2 of this article - have you read part 1?

Click here to do so!

* * *

If you spot an error please report by leaving a comment below.

If you don't, your comment is still appreciated. ;-)

Sources:
http://www.acill.com
https://github.com/arananet/A4000db 
https://github.com/endofexclusive/greta
http://www.amiga-news.de/en/news/AN-2016-04-00050-EN.html 
http://www.nemesiz4ever.de/board/thread.php?board=1&thema=11

The awesomeness: Amiga hardware news - galore! (1/2)

It sounds too good to be true, but in these cases it isn't a hoax. There is a lot, and may I repeat, A LOT going on in Amiga hardware world... In fact it's so much I've split this into two parts.

7-bit's SPI controller for the clockport

On April 24th 2018, 7-bit Retro Electronics announced a new product: The "SPI MasterBus CP" controller for the clockport.

SPI is a simple, flexible, fast serial data interface that allows multiple devices to be connected. It's used by numerous types of devices across all computer platforms, e.g. as an interface to memory card readers (SD, SDHC, CompactFlash, ...), ethernet controllers, flash memory, for CPLD programming, and many more applications.

That makes a fantastic addition to the Amiga's capabilities!

Here are some "SPI MasterBus CP" specifications:

Designed for Amiga A1200’s clock port
SPI bus clock speed: 25 to 195 kHz
Full-duplex data transmission
Up to 4 devices with Slave Select lines

Built-in software will allow you to manage several characteristics of the controller.

Here's an early video showing SD-card access in action:

https://www.youtube.com/watch?v=j7HeQqHj56o

Keep an eye on their website for full specifications, project progress, and availability:
https://retro.7-bit.pl/?lang=en&go=projekty&name=SPICP

Jeroen Vandezande's Amiga 1200+ mainboard

With increasing age, Amiga 1200 mainboards (among others) run the risk of taking damage from leaking capacitors, and of course over a timespan of about 30 years there are a lot of other factors that may shorten - or quickly end - a mainboards life.

Wouldn't it be nice to just have the opportunity to purchase or make a new one?

This is one of two projects (see below for the other one) recreating the Amiga 1200 mainboard, Jeroen's "Amiga 1200+" is an updated version with some changes.

The project is covered by Creative Commons license, and you are free to build your own mainboard!

Here's a list of changes compared to the original Amiga 1200 1D4 mainboard, taken from the project website:

• Gayle, Budgie and the DRAM have been removed and the functionality has been moved to a daughterboard. This board can also contain a CPU.
• Video output has been moved to a seperate output board. This board get all Lisa output signals and also all the typical Zorro signals. This means that an RTG card can be developed.
• The PCMCIA slot has been removed and in the free space a power switch, boot selector switch (DF0:/DF1:) and a uSD card slot have been added. 
• A single supply universal power input has been added. (15V - 36V)
  From this the following voltages are created:
  * 5 Volts: main power rail 5 Amp capable
  * 12 Volts: 1 Amp capable
  * 3.3 Volts: 0.5 Amp capable (for daughter boards)* 1.2 Volts: 0.5 Amp capable (for daughter boards)
• Two PC standard 3 Pin fan headers are added to the board. 
• Terrible Fire compatible SPI port for network chip 
• Extension board connector for mouse/joystick. (One is in development that has USB Mouse and two classic DB-9 connectors and autoswitches when fire button is pressed.)

The "Terrible Fire compatible SPI port" is an especially nice addition: it shows that Amigans work together - way to go!

Now head over to Jeroen's website, and start building your enhanced Amiga 1200:
https://bitbucket.org/jvandezande/amiga-1200

John Hertell's Amiga 1200 replica and ReAmiga 1200 mainboards

The other project recreating the Amiga 1200 mainboard comes from John "Chucky" Hertell, well known Amiga hardware guru.

He had already created the A3660 Amiga 4000 replacement CPU module (see http://wordpress.hertell.nu/?p=537 and http://eab.abime.net/showthread.php?t=89200 if you want to know more), and asked the community for his next reverse-engineering project, which turned out to be the Amiga 1200 mainboard. Well, about two months later, and with the help of other members of the Amiga community, Mr. Hertell had a clone of the original 1D4 version mainboard in Gerber file format!

But he didn't stop there, adding some modifications to the board - here's a list of changes:

• Supports round and square powerconnector
• New reworked composite video logic, with additional S-Video support
• RF-Modulator removed and replaced with optional buffered VGA connector
• Selectable SEL signals for floppy
• Optional NMI (IRQ7) possibility
• Resetheader
• A500 compatible keyboard connector (currently untested)
• Support for the Ratteswitch with solderoles for required signals so no need of a socket on CIA
• Extra powerconnectors for +12 and +5V fans, and extra powerconnector close to CPU slot
• PCMCIA reset fix
• Optional onboard LEDs where LED and +5V are separated also optional “opt” led, with jumperwire for PCMCIA activity LED

 

http://wordpress.hertell.nu/wp-content/uploads/2018/08/A1200pcb.jpg

Well, what can you say - another awesome job by Mr. Hertell.

Check his website for complete first-hand information, and files required to build your own Amiga 1200 or ReAmiga 1200 mainboard:
http://wordpress.hertell.nu/?p=587

Note that you can also buy ReAmiga 1200 PCBs from Mr. Hertell - income from these sales will partly be donated to Swedish children cancer fund. See link above.

 

Commodore Amiga AA3000 / A3000+ recreated

Both Matthias 'Matze' Heinrichs' and Christian 'Scrat' Euler have recreated a legend: an AGA-chipset equipped Amiga 3000!

Sadly, there's no open source re-creation (yet?) of the mainboard, probably due to technical difficulties (8-layer board) - but nontheless, this is another great example of the capabilities of the Amiga community. Who would've thought we'd see these ultra-rare machines outside of Commodore's laboratories one day?

Read the full story with pictures and files over at amiga-news.de:
http://amiga-news.de/en/news/AN-2018-08-00030-EN.html

* * *

That's it for today - 

click here to read part 2 with more amazing Amiga hardware news!

* * *

If you spot an error please report by leaving a comment below.

If you don't, your comment is still appreciated. ;-)

Sources:
https://retro.7-bit.pl/?lang=en&go=projekty&name=SPICP
https://retro.7-bit.pl/?lang=en&go=aktualnosci&view=132
https://bitbucket.org/jvandezande/amiga-1200
http://wordpress.hertell.nu/?p=587
http://eab.abime.net/showthread.php?t=93015
http://amiga-news.de/de/news/AN-2018-08-00030-DE.html
http://www.bigbookofamigahardware.com/bboah/product.aspx?id=23

Amiga 4000 mainboard goes opensource!

Amiga 4000 mainboards are becoming rare these days, and are difficult to repair. But there's hope in sight. A lot of hope. In fact so much hope that you can almost grab a new one! Yes, we can make this happen!

Paul Rezendes from California, USA, has started a funding campaign to have PCB data files professionally recreated from an Amiga 4000 mainboard, and publish these under open-source license.

(This does not include any boards actually being produced - it's only about the data files required to do so.)

Now let's think about this for a second. First thing that comes to mind is that some hardcore Amigans will produce a few new mainboard from the data files, for repairs, or maybe build an A4000. But the really exciting stuff starts when people start modifying the PCB. Just imagine the possibilities... PCI onboard, a new low-cost CPU card connector, streamlined design getting rid of old/unused components, scandoubler onboard, (Mini)ATX formfactor, ...this has the potential to become a quantum-leap forward in Amiga hardware development like the Vampire boards are!

Here's Paul's GoFundMe campaign page:

https://www.gofundme.com/amiga-4000-replica-with-schematics/

Note that GoFundMe does not accept PayPal - if you want to donate using PayPal, the guys from Amiga On The Lake are watching this campaign, too, and are happy to receive your donation and forward it to Paul Rezendes' GoFundMe account!

http://amigaonthelake.com/aotl-donations/

Now head over to GoFundMe or Amiga On The Lake, and make your donation!

We're almost there! Yes, we CAN make this happen!

https://d2g8igdw686xgo.cloudfront.net/28730374_15223301610_r.jpeg

Help! Microbotics / Paravision M1230XA accelerator board repair

*****************
UPDATE 2018-02-17:
Yesss, it works again. Another gem saved. Microbotics' "MBRTest-2" tool from the M1230XA install disk does an excellent job of testing (any) RAM. FastRAM installed on the M1230XA can be tested even without adding it to the system. That way I was able to diagnose the problem, and fix it (see picture below: green wire fixes some broken address- or data line). The board also got some new capacitors.

Thanks to everyone who helped me! :-)

*****************


I have an old Microbotics / Paravision M1230XA accelerator board, and it's not working properly. Can you help me debugging it?

For starters, a few screenshots would help: SetXA utility window / running, Early Startup Menu boards listing, "showconfig" output, SysInfo screen with speed test results (each of course with a working M1230XA installed).

I mostly test my board with Kickstart 3.0 - are you aware of any issues regarding KS3.0 and the M1230XA?
(apart from the fact that RAM has to be added "manually" / software-wise)


Please leave a comment in the comments section below, if you think you can help.

Or contact me via amiga.org

Or via amigaworld.net


If you want to keep track of my efforts debugging/repairing the M1230XA it's maybe best to watch my "Microbotics / Paravision M1230XA accelerator board information" page.


Thanks!

- - -

Situation / Error description:

The Microbotics M1230XA seems to work fine without memory installed.

With memory installed, adding the memory to the system doesnt work.

This is the situation with a Kickstart 3.0 Amiga 1200:
In the picture below you can see the previous settings ("RAM Speed: 100nsec", ...), new settings("setxa ramspeed 70", ...), and the state after adding the board's memory. After "setxa addmem", it takes maybe half a second to activate the memory. During this short timespan the Amiga remains usable - e.g. a mouseclick on the workbench. But once the memory has been added, it looks like any memory access fails. That includes (re)focussing the shell-window, clicking an icon. When keeping the shell window active (no workbench click), keyboard input is still possible, but entering a valid command and hitting <Return> crashes the machine.

Behaviour is almost the same with different RAM SIMMs/speeds/cycles, only the type of system crash differs: sometimes screen graphics corruption, sometimes black screen, sometimes Guru Meditation.

With a Kickstart 3.1 (=autoconfiguring) Amiga 1200 the screen stays black on powerup.

AMIGA alive 01: Amiga 500 keyboard membrane repair (Video)

"AMIGA alive 01 - Amiga 500 keyboard membrane repair" is out. We're doing a little repair job to the A500's keyboard membrane, and show you some of the individual parts the keyboard is made of. Hope you enjoy it - comments welcome!

https://www.youtube.com/watch?v=48B2bSaZPpI

 

New page: Using PC floppy disc drives with the Amiga

As you can see on the right side, there's a new page about PC floppy disc drives and the Amiga. If you have some information (links, experience, ...) on the subject please share by leaving a comment. Thank you!