Amiga 600 SD to IDE HDD LED Always on Explanation & Fix

[@JanBeta]

The first 1000 people who click the link will get 2 free months of Skillshare Premium: skl.sh/janbeta0820

[@kundenbetreuung4921]

I came across the problem with the LED myself a few weeks ago when I converted an A1200 to CF. And you are absolutely right: You don't find too much information about it on the net. In the end I modified the adapter with a 20K resistor. Thanks for covering this topic in a video :)

[@gertsy2000]

It's always good when you can fix something using something someone has built for the fix. Makes life simpler.

[@JanBeta]

The adapter also fixes a number of issues at once (like how to secure the SD to IDE adapter inside the Amiga). :)

[@MindFlareRetro]

Great info! I have my first A600 requiring attention. I was not aware of the KA-47. I will have to snag one of those, for sure.

[@bretttesdall2155]

Just bought 2 KA-47's to proactively correct this on the ReAmiga 1200 builds I'm working on! Thanks!

[@10MARC]

Jan Beta Confidently "That's our whole problem here... I think..." "If I got it right the first time, I wouldn't be me" This is why we love you, Jan Beta! Never change!

[@ArjanvanVught]

The most important here is the HCT version, the T; it runs at 5V and it accepts 3V3 logic. HCT (buffers) are typically known for driving 5V logic WS28xx chips (pixels) with the 3v3 logic SoC/micro-controllers.

[@JanBeta]

Makes sense! Thanks for sharing. :)

[@e5frog]

​@@JanBeta The nice holder is a big plus, it seems a 5V source, diode and resistor would have solved the level transition as well and you wouldn't have to buy and wait for a finished solution. HCT is CMOS but has the same voltage thresholds as TTL, about 2V for high input - and has output close to VCC (5V) out - so that solves a level difference, plain TTL could result in a lower output but may have worked as well. I'm not sure the hysteresis of a Schmidt-trigger is needed here, but why not? Using just CMOS you need about 3.7V for high level - so 3V3 doesn't do it - which is probably the source of the problem. I wonder if a simple pull-up resistor couldn't have solved it...?

[@infopackrat]

So wouldn't it be better to just use a 74HCT244 buffer?

[@TPau65]

The KA47 solution really is the best of them all! No ribbon cable, fixed position for the SD/IDE adapter, nice! 👍

[@brostenen]

I used it too, some time ago. Yet I am using an angled CF-IDE adaptor and running with an Microdrive.

[@alex76gr]

I have the same problem on my A1200 with this SD->IDE adapter. Thank you for the heads up!

[@brianhginc.2140]

Another authentic full LED off fix would be 3 diodes in series, something like a 1N914 or 1N4148 would do. This would allow an additional 2.1v above 3.3v, IE: the IO needs to drop below 2.2v, your new threshold before the led would begin to turn on. The LED wont begin to shine at all until that IO goes below 2v. No ICs needed. My listed diodes are available in axial wire, or smd variants exist.

[@glonch]

Well done. The IDE riser was very cool and a great solution. So much better than the cable and having the card float around.

[@JanBeta]

Yes, I think it's the best solution for a number of problems (including the LED). :)

[@arambp77]

Thanks for the free 2 months of skillshare!

[@TheBookaroo]

Hi, i think it works because the resistor will bring the 3V up to 5V as a pull up resistor but it will not prevent a ground to be ouputed. Thanks for the videos, now I have to find a C64 for myself...

[@8_Bit]

Interesting! Commodore's Datasette uses a Schmitt trigger to turn the analog tape signal into a digital signal.

[@EduArana]

The a600 is one of the most Amiga that I like apart from the A3000. Great video as always Jan. Keep it up.

[@JanBeta]

Thanks Edu! The A3000 is my favorite Amiga overall, I would say. Wish I had one. ;)

[@stephenbruce8320]

I never encountered that issue but when I did pick up a FURIA the KA-47 and IDE2SD Board was recommended so I went that route and when I got tired of the Furia not being quite compatible with 3.1.4 I changed it out with a Vampire and never looked back. So I never ran into the HD LED Light issue so I got lucky but the KA-47 is a nice little board and it allows air flow around the IDE2SD Board which is also nice. I do like the SD Solution better than the CF Cards which have been known to drive me crazy working great on some systems and not others vs some that work well no matter where you plug them in so whenever I can use and SD Card over CF its SD all the way.

[@arbutuswatcher]

Nice buffer circuit. Next week boolean algebra & logical truth tables? ;) I've seen similar solutions utilizing the MAX232 chip for serial (RS-232) applications. On analog projects I've had the occasion to use a discrete transistor, as a switch, when no logical inversion is required, to control a LED. Saturation for an on state, & Cutoff for an off state. Nice fix, to complete the project. :)

[@blackcountryme]

Yay Jan Beta has turned Into BigCliveDotCom!

[@neur303]

I think the resistor solution allows Vcc of the Amiga to pull the output high via the pull-up and the diode part of the transistor. A bit like with open collector outputs. I think 3 standard diodes in series instead of the resistor would also fix the issue with the dimly lit LED. Reasoning is you need to offset 1.7 volts .. 3 x 0.7 -> 2.1V Current will only flow when the difference is higher than that. Since it is fully lit with only 1.7 Volts already a 2.7V zener diode might also work perfectly.

[@philrod1]

This is what I was thinking. Just bump the voltage a little so low is ~1.7 and high is ~5. Does the job but seems a bit getto.

[@ianide2480]

At a 5v VCC the trigger is likely around 2.8(ish) volts. So at a 3.3v output, it'll trigger immediately. For the downslope it will trigger again at 2(ish) volts. Anyway they are great for outputting a nice clean square wave. It seems that I use these quite often for operating Logic Level MOSFETs, and I've also used them for logic conversions of 3.3v to 5v. Handy item to use and you get 6 triggers in a 14 pin package.

[@SianaGearz]

I don't think you need to necessarily beautifully signal-shape an LED drive signal. Just look yourself at the schematic you show at 4:32. There is a local pullup 10K to VCC, so that when nothing is connected, the LED is not lit. The circuit can also be driven open collector/ open drain. However when a modern 3.3V IC is connected, it will have on every IO, an ESD diode to 3.3V, so it hard clamps the voltage to 3.9V instead of the desired 5V on _IDE_LED line. Installing a resistor that is significantly higher than 10K allows the pullup to take over effectively and get much closer to 5V. However when the _IDE_LED line is pulled down to activate by the IDE device, and the desired voltage is 0, it will naturally be higher than that. However given that the issue is present to begin with, and e.g. 3.9V drive is sufficient to activate the LED, you have a huge range of inline resistor values where both states will work well, it's not actually a particularly fragile solution, at least for the given mainboard schematic. I think an open-drain drive with BSS138, 2N7000 or 2N7002 would be actually great and unconditionally robust.

[@SledgeFox]

So much to learn, thanks to your videos. Thank you very much!

[@barnabas5688]

For anyone who buys one of the little SD to IDE adapters I would advise you to check the soldering carefully on the IDE connector before you power it on. On one that I bought, there were 2 pins bridged with solder and a burned out IDE cable and lots of smoke resulted. Ironically, this happened the first time I attempted to boot a new Terrible Fire card that I recently built, so I actually had a terrible fire...

[@briangoldberg4439]

Looking good! When are you going to retrobright that mouse?

[@perhansson6718]

11:50 megaburken is Swedish slang: burken in the context of computers literally means "the computer" and mega has the same meaning in English, so megaburken is the server that runs the website you visit :)

[@xyzconceptsYT]

Thanks Jan, keep up the great work. :)

[@douro20]

What is the game you were running in the beginning of the video? Metrix used to make these nice hybrid oscilloscopes which had both analog and digital modes. Mine is an OX 8020 which is a 20MHz scope with a 40MS/s real-time digital mode. It will store the last waveform to be viewed in memory and you can even print the waveform and its characteristics on a parallel printer or plotter.

[@JanBeta]

The game is Speedball 2. My Hameg has some storage capability but nothing like a one-shot trigger and other useful things that the more modern DSOs have. I'll have to get a more modern scope sometime I guess. :)

[@pvc988]

TLDR: Some series diode(s) would shift both levels up by a drop voltage on said diodes. Enough to make it work. Current is probably geting from Amiga VCC through transistor E-B junction through adapters internal voltage clamping diode to 3.3V supply. One diode drop from 5V to 3.3V is still 1.1V which is enough to turn the transistor on. Extra diode in series with _IDE_LED signal should lower E-B voltage of the transistor to about 0.5 which should be enough to turn it off. If not, add 2 series diodes, which should drop the E-B voltage near 0V. All that at the expense of setting low level output voltage from the adapter to about 0.6V (or 1.2 in case of 2 diodes).

[@eDoc2020]

I was also going to suggest using two series diodes on the line, with the cathodes pointing to the drive. This will work on the Amiga's circuitry but with other computers may disable the indication entirely.

[@jaycee1980]

I think it is actually that the adapter violates the ATA standard for this (i could be wrong!). Ordinarily, the LED output on a drive is open collector, so it's either low (connected to GND), or high impedance (open circuit). The base of Q631 is normally kept high by R631, and that means no emitter-base current (because it's a PNP transistor) can flow, so the transistor remains off. With _IDE_LED at 3.3V, there is enough emitter-base current flowing to light the LED. The MOSFET fixes it because it is effectively making the _IDE_LED output "open drain", so R631 can now do its job and pull the base of Q631 to 5V. A PC probably passes the signal through a CMOS gate of some kind, so even if the gate was supplied by 5V, 3.3v would be a valid logic "high".

[@jaycee1980]

I found a description here www.ele.uri.edu/courses/ele408/s2001/projects/roland_ide/ide.html - the signal is called "DASP-" there. It is specified as an open collector output with a 10K pullup to VCC. If the SD adapter had implemented it like this, the 3.3V output would be less likely to switch Q631 on.. it may still do, but the LED would light weakly. An easy fix for that would be to reduce R631 to say 4K7, so it can source more current and keep Q631 biased off

[@jaycee1980]

Now I have watched the video properly ;) The resistor solution is simply allowing less emitter-base current to flow while the output is high, and it drops this current flow "enough" that the LED appears to be off.. but as you noticed, it is not completely off. The MOSFET version is using the MOSFET as a level shifter. This is actually quite commonly used in 5V/3V3 mixed systems. The gate is held at 3.3V, the source connected to the lower voltage, and the drain connected to the higher voltage. If you google "mosfet level shifter" you will see lots of examples of this. The pullup resistors are already present on both the SD adapter and the Amiga itself, so only the MOSFET is needed. 2N7000 or BSS138 are very typical parts for this task RastPort's solution is using the inverting input schmitt trigger works exactly as you suggest... it's fairly overkill, but because 3.3V is not available at the ATA connector, it's probably the best way to do it. a Picogate would have been neater, but the 74HCT14 is probably the cheaper part!

[@SianaGearz]

@@jaycee1980 The spec suggesting open collector output somewhat conflicts with the desire of modern IC makers to have ESD protection on every IO pin, less trouble for them and their customers that way. So if there is no 5V anywhere on the IC, there would be a clamping diode to the chip's corresponding VCC being 3.3V from every IO pin, limiting the voltage effectively to about 3.9V.

[@danielson9579]

An amiga 600 was my first amiga 🙂👍

[@geofftottenperthcoys9944]

Same.

[@psteier]

That resistor trick was exactly the first one I've done to my A600... still running it.

[@JanBeta]

Does it turn off the LED fully for you? I read some people had problems with that (probably depending on the resistance you choose).

[@psteier]

@@JanBeta as far as I remember (A600 is not attached/stored right now) it does.

[@AngelFernandezA]

@@JanBeta I think you correctly guessed the way that new resistor fix works. Pin 39 is an open collector output, so adding a resistor and joining to the other end to the _IDE_LED_PIN makes effectively a voltage divider. Assuming no current flows from the transistor base: - R631 (10k) is tied to Vcc (+5V) - Pin 39 (3.3 V) is tied to the other end of R631 via that new resistor - 5 V - 3.3 V should drop in the "voltage divider" (R631 + new resistor), such the new joining pint must be at least at 5 V - 0.7 V (Vcc - Vbe) for the transistor Q631 to be OFF - New Resistor should be, at least, around 20k ohms. So, when PIN 39 is low (led should be on) from Vcc = 5V the voltages are: 0.6 V (or less) drops on R631, 1.2 V drops on the new resistor and pin 39 is at 3.3 V Low values for the new resistor make the join point to have a low voltage, so transistor Q631 is ON and led is ON too

[@bigandyt-man3010]

Im so glad you explainded it... (Thumbnail spelling) lol

[@martinclark1411]

i have an ide to msata adapter which had similar issue (hdd light dimly lit constantly) stuck in an old eide99 adapter i had laying around, worked perfectly and in addition is now buffered i believe

[@heidirichter]

This is wonderful, thank you so very much! I'm going to have to get one of these!

[@jorgecristianhenriqueztolh3999]

I think the simplest solution is the resistor. In the adapter’s high output voltage it shoud provide enough voltage drop to Lower the PNP base polarization voltage to shut it down. And if the resistor value is proper, at low output it shoud provide enough base polarization to saturate the transistor.

[@brostenen]

I love my 600 as well. They are awesomme small machines.

[@stephencothran3702]

Nice Shirt, love that band.

[@akkudakkupl]

That output on IDE should be open collector (or drain), all needed for a fix is diodes in series with that line ;-) Could have cut the wire that controls the led on the ribbon and just solder 2x 1N4148 pointing towards the SD2IDE interface in it.

[@vix_in_japan]

The blinky light was always part of my Amiga 600's charm....although 8850km away from me right now, she's not so blinky, but she's missed.... As is my squeak zipstick....

[@JanBeta]

Hope you two are going to be reunited soon! ;)

[@derre98]

You explained what a comparator is, but a Schmitt trigger is a bit more so the way you drew and explained the thresholds is a bit incorrect. Schmitt trigger has hysteresis so unlike a comparator, it needs to go way back to return to the previous state and not just cross the same threshold again. Schmitt trigger has two different thresholds depending on from which state the change is happening from so 0->1 threshold is different from 1->0 threshold and due to this, a Schmitt trigger offers more immunity to noise when compared to a comparator (no pun intended). Of course for driving an indicator led, this is pretty much irrelevant, but for other circuits it can be significant.

[@JanBeta]

Yes, true that. I oversimplified things quite a bit. Thanks for the explanation!

[@spudhead169]

The added resistor may be paralleling another resistor on the board maybe? That would lower the overall resistance.

[@marcinnowak7811]

I used MOSFET method on my A600 and it worked for me. There is also a picture showing how MOSFET should be soldered. megaburken.net/~patrik/Amiga%20SD%20Adapter%20HD%20LED%20Fix/example.jpg

[@JanBeta]

Ah, I'm going to add the link to the video description. Thanks!

[@Xoferif]

A really nice bit of freeforming! =)

[@kriswillems5661]

A schmitt-trigger normally has an hysteresis. What you show is your drawing is a comperator.

[@benbaselet2026]

Your trigger explanation missed the fairly important fact that the high and low triggers are separate and there is a rather large gap between them so if you have a noisier or weak signal it will not oscillate the output between high and low because of the hysteresis in the middle. So it just picks the "real highs" and the "real lows" and not anything in between.

[@temporarilyoffline]

That yellow mouse looks like its lit up from inside. Its so bright its glowing.

[@guyh3403]

I feel sooo sorry for tossing my (working) A1000 in the bin after storaging it for decades. I should have sent it to you :( If only it was for parts.

[@twocvbloke]

Much like with the Amiga issue, my Toshiba Libretto 50CT has the same "always on" issue with a CF card adaptor, though in this case I think it's the CF card itself not outputting activity, as I'm sure I've had CF cards in there that did work (or I'm thinking of my Fujitsu netbook (wherever that is!) which got used for CF experiments before settling on an SD-IDE), computer works fine, it's just annoying having the HDD LED always on... :\

[@JanBeta]

Yeah, I think some CF cards don't output that signal (probably because most CF adapters don't make use of it anyway). It's a bit of hit and miss to find compatible cards these days. :/

[@holleholl3057]

Seems to depend which SD-Card converter you actually use , maybe it has got something to do with the revision of the Amiga-mainboard you use as well. Both my Amiga 1200 and Amiga 600 work with a SD-Card to IDE-converter without any LED-issue at all ;)

[@JanBeta]

I read somewhere that some older SD adapters output higher voltage so they work without any modifications. Probably you got lucky and have those versions. :)

[@francoisrevol7926]

Well yes Schmitt triggers have two thresholds, else they wouldn't be Schmitt triggers :-D I'm not entirely sure it's really required here, it's just used for the voltage adaptation between the 3.3V and the 5V circuits. As for the resistor fix, it raises the voltage on the transistor's base by just enough to make it not active, instead of 3.3V, it would be 3.3 + R*I with I the current from the base and the pull-up resistor. Another possibility would be to use a diode in series instead, which would add its own threshold voltage, but it would need some calculations to make sure it'd be enough.

[@JanBeta]

Yes, I've seen people using diodes, too. Seems to work fine but the Schmitt Trigger fix is a bit more elegant obviously. :)

[@markdjdeenix6846]

Very interesting jan thanks 😎

[@JanBeta]

Glad you found it interesting. :)

[@markdjdeenix6846]

The ide pcb looks like a good work round .and how the chip works I found interesting and it seems a better way to hold the sd card pcb in place

[@Lee_Adamson_OCF]

Huh. I think a plain ol buffer or inverter ought to work. A 3.3v signal from the cf card ought to be well above the TTL threshold and switch the output appropriately. Maybe the 7414 was cheaper. :3

[@richardblack5710]

What is the blue card in the KA47? Looks too big to be an SD card.

[@maksimivanov5516]

The new home of keyboard virus xD

[@JanBeta]

Yes! The Amiga schematics are full of funny lines like that. Actually put there by the engineers.

[@EllipticDawid25]

Hi can you shut case proper with this adapter ?

[@larsenmats]

I think that's the adapter card I ended up with to fix this problem.

[@HelloKittyFanMan.]

Hey, am I dreaming, or is this your first video with your full-face reveal? Or did you do that a long time ago?

[@charleseslick3336]

Voltage is directly proportional to resistance is the reason for the voltage gain .

[@Cassandra_Johnson]

Looks like your system's 5v line is sitting a little low, closer to 4.5 volts.

[@JanBeta]

Ah, I think the scope was not perfectly set to zero. The voltage is closer to 5V than it looks I guess.

[@mrfrog8502]

Another way of fixing this is by placing a small signal diode in reverse polarity directly on the flex cable on pin 39.

[@jensschroder8214]

two inverts give the same 0 = 0 and 3V => 5V . all other inverts have no funktion and are tite to 5V

[@doktork3406]

Oh thanks i really needed this to fix mine wait.. thanks algorithm for bombarding me with this HAPPY?

[@HelloKittyFanMan.]

"Floppy" and "disk"? Whoops, they screwed that pooch, didn't they?

[@Spiderelectron]

The scmidtt trigger normally has two thresholds - a high threshold to come 'on" and a lower threshold before going 'off' again.

[@JanBeta]

Yes, you are right. I oversimplified things a bit in my head.

[@Spiderelectron]

@@JanBeta No worries! Thanks for the reply! I enjoy your videos very much. I am old enough to remember all these machines from my teenage years. I could not afford anything as exotic as an Amiga or ST, or even a C32 - I had a Mattel Aquarius - in fact I still have it. :-)

[@UberAlphaSirus]

Would this ide-sd work on a A500?

[@e5frog]

An A500 usually has no IDE interface unless it was added (there are for example a version that connects over the CPU). You will need some kind of external or internal IDE-interface to be able to use one of these.

[@UberAlphaSirus]

@@e5frog so I would need that side loading hd module then. I was hoping there was a modern interface module al ready to go with a CF or SD card. Also hoping to be all internal to keep the footprint down. I spose I will have to continue with my gotek.

[@e5frog]

@@UberAlphaSirus You don't have to, you can get one similar to the IDE68K module that is placed between CPU socket and CPU. Then you'll get an internal IDE port - but you also need to change the Kickstart as the original v1.2 or v1.3 won't handle it. I've got one in my A2000, works perfectly fine.

[@UberAlphaSirus]

@@e5frog well I have all the gear to make roms. I have modded my c64 as a near stand alone console. I would be really interested if you know any guides or modules available to get the 500 or 500+ solid state hard drive. Soldering and skills are not a problem. Knowing whats about is. Thanks for your help.

[@awilliams1701]

My C64 PSU is 5V DC 5amps. But for some reason with the U2+ cartridge installed I was only getting 3.5V. Without it I was getting 4.5V. As far as I can tell I'm still getting 5V at the point where it enters the C64. So I have no idea why it drops that much. Once I realized it was running at 3.5V, I'm like no wonder why it's glitching. I HAVE NO IDEA HOW THAT C64 was working at all. It shouldn't have worked, but it was working well for everything except video. Ironically the same PSU powering the C64 is now separately powering the U2+ and the retrotink. So I have no idea what could cause that. But yeah no more video glitches!!! It's odd it actually got worse. It started with just impossible mission and giana sisters glitching. Eventually it was everything including sam's journey. Anyway now I have the VIC-II² mod installed so I have both NTSC and PAL modes. I think I actually found a game that doesn't like PAL. I'll have to double check.

[@e5frog]

Could be voltage drop over the power switch or a shorted cap drawing current. Did you measure the current drawn?

[@awilliams1701]

@@e5frog no but the caps are new and the switch is new. The old switch definitely had issues.

[@HelloKittyFanMan.]

Hmm, it's ironic that one thing's "on" condition depends on an "off" signal, instead of, say, a light being turned on by a high signal.

[@HelloKittyFanMan.]

Or you could just lengthen (if necessary) and redirect the wires from the Amiga LED to a parallel connection on the little board.... if you could solder it fine, that is.

[@eDoc2020]

Unfortunately you can't do this because all three LEDs on the Amiga share a single common negative wire. You would need to modify the LED board in the keyboard. At that point the resistor mod would be much easier (and not require modifying the Amiga)

[@HelloKittyFanMan.]

@@eDoc2020: Yes, you can, because: 1. I wasn't talking about modding the LED board in the keyboard. I was talking about simply removing that LED from there and soldering it via wires to that other board, and 2. you just contradicted yourself by saying "and not require modifying the Amiga" when you said "the resistor mod." And I wouldn't recommend the resistor mod anyway, because this modification that he settled on is even better than that, as he stated. But you could do my suggestion if you just didn't feel like ordering one of these.

[@eDoc2020]

​@@HelloKittyFanMan. I thought you couldn't disconnect the LED from the keyboard without modifying the board, but I'm not an Amiga expert so I could be mistaken. Also, I thought the resistor mod was done on the SD2IDE and did not modify the computer itself. Either way there are lots of ways to get a working LED but they all have their own pros and cons. Assuming your method works it's a great option, probably the best that doesn't require additional parts.

[@HelloKittyFanMan.]

@@eDoc2020: You can desolder something from a board without changing the board, LOL! Also, just plugging the other card onto that circuitry inside the Amiga is something you already called a mod. My method would work because the only thing it is is paralleling it with the LED that's already on that board. But if that other little board is easy to get and install, then I might like it better.

[@conradtrout]

That Amiga mouse has yellowed so much I think it's turned radioactive.

[@DaveMcAnulty]

I think you just needed a not gate.... 3.3v is enough "on" for ttl or cmos.

[@SianaGearz]

What you're thinking of, basically every well-specified 5V IC has a logical threshold voltage that is well below 3.3V, so you can just communicate in that direction reliably directly. But this signal from 3.3V device doesn't go into an IC, it goes into an discrete drive circuit for an LED, which has been designed sloppily to work just well enough with the 5V output chips that they had at the time. It's a base current limit resistor and a transistor, and the resistor value is low enough to just always leak enough current to light the LED when there's 3.3V on the other side. You can see the schematic at 4:32

[@zero0ryn]

You could have put 3 diodes in series giving you 2.1v drop. It would be enough to trigger that LED.

[@hotlavatube]

So you're saying the adapter is full of Schmitt... ;-)

[@djbase_]

Gibt auch Open Source Lösungen für solche Adapter www.amigaworld.de/hardware/amiga-600-1200-ide-adapter/

[@thegreatjonzini]

Bikini kill! Nice 👍

[@JanBeta]

Yes!

[@retrokaszubfan]

@UCftUpOO4h9EgH0eDOZtjzcA​ Amiga 600 weißer Bildschirm Was könnte es sein

[@retrokaszubfan]

Amiga 600 weißer Bildschirm Was könnte es sein