Tuesday, 27 June 2017


As mentioned in a previous post http://exxosnews.blogspot.co.uk/2017/06/falcon-buffer-patch.html
I have now finished a second batch of the Falcon Clock Buffer Boards.

I have done about 30 of these in this batch.

I tested them all with a 16MHz Oscillator on breadboard and scoped out everything was working as expected :)



Monday, 26 June 2017


I had a motherboard sent to me from a chap in the USA. Apparently he was fitting a CT60 and managed to kill the motherboard while swapping PSU's about :(

Which PSU exactly caused the issue is unknown as there was ATX and PICO PSU's involved. Though it was one reason I was motivated to do some reviews on PICO PSU's  to test the regulation out. I have already seen a lot of PSU's spiking up to several volts even with new PSU's. So be warned!

The machine came to me with a whole host of mini nightmares to go through.  One of which was a  failed NVRAM replacement.  It seems the guy tried to cut the pins as close to the motherboard as possible to remove the old NVRAM. Though doing that means the pins are stuck in the PCB holes and nothing to really get any heat onto them with, and nothing to pull to get the pins out! This turned into a nightmare to fix.

Normally you cut the pins as high up as possible, heat the pin up,  pull it out. Simple stuff. Though with the pin basically being chewed up, in the hole, top and bottom. well, lets just say it took "some time" to correct it.  I also found a track had been ripped up at some point (wasn't me!) so had to repair that also.

In the end a socket was fitted and the track repaired.

I also had to remove a bodged clock patch install and do some repairs to the motherboard to get it back to "stock".

On power up...

Total chaos!  Oddly though, the machine did actually seem to be running as I could near the floppy drive loading stuff up off my boot floppy! So the machine was running, just no video on RGB or RF :(

After some scoping about I suspected the Videl was chucking out data, but there was nothing on the output of the video DAC.  So.. Out it came..

..and in with the new..

On power up...

Nothing had changed! crap!!

Much pondering later it seemed Videl was suspect in the data it was feeding the Video DAC. I did a lot of comparisons between my spare Falcon and this machine and while it was hard to compare as the faulty machine had basically a black screen, I did suspect the Videl wasn't outputting what it should be.

I also back tracked to COMBEL and traced all the video load/select lines were triggering, and they was.  So COMBEL was telling the Videl to load data, just it wasn't getting the the Video DAC :(  So this means the only likely cause is the Videl chip is dead.

So, Sometime later.. A new Videl IC turned up... So out with the old...

 .. and in with the new..

 I had never attempted to change a IC of that size before, so wasn't really expecting anything "good" to come out of it.

I did ponder about using a stencil to apply solder paste, but decided to paste it by hand and add some extra flux to the pads.  Its a technique I developed over time as I never liked the apparent "easy" methods of "flux and drag" with a soldering iron.  It looks easy, but dragging the iron oven pins can bend them. It can damage "cheap" PCB pads. The problem I always had was solder would always end up behind a couple of pins and you could hardly ever see it.  More to the point, its pretty impossible to get the solder "un-stuck" regardless of the amount of flux or heat used.  The only option was to remove the IC and clean it up and start again.

So what I did , which is what I do mostly now, is to run SMT paste around the edges of the IC pads and add flux on the middle areas of the pads. Then plonk the IC on top and heat the sucker up. The flux melts and covers the PCB pads and the IC legs, then the SMT paste melts and  have a easy flow between the IC legs and pads and it gets "sucked" into place by capillary action.

The good thing here, SMT paste only gets on the bottom of the IC pins and there is practically no risk of solder creeping up the legs and shorting them out.  Probably the worst case here is the need to add a little more paste and re-heat if the SMT paste was applied to thin on some pads.  Its better to add solder later than try and get excess off!

So power up we shall...and..

"Another successful repair" as we used to say in my old workplace :)

Of course its going to have my clock buffer patch added soon along with a new  AXIAL CAP to replace the aged one.

With the PSU being the likely cause of killing this falcon, a quality input capacitor will help smooth out all the nasty spikes in those "cheap PSU's" and help protect the motherboard from them.

Considering the Videl is right next to the PSU connector, there is no great surprise that it was killed first. Of course the owner of this board really, got away lightly as the PSU could have blown a lot more IC's and the board would have been a total write-off!

Friday, 23 June 2017


While working on the new 30 pins simms for the STE. I had the thought to solder some header strips onto a few sets for those people who do not have simm sockets on their STE.

These have round header pins (0.5mm dia) and can plug into round header sockets or be soldered directly to the PCB.

Likely these SIPP simms will fit other machines needing them also. 


Wednesday, 21 June 2017

40x 1MB 30pin simms RESALE PACK

I have been asked  a few times about selling in bulk for people to re-sell them. I don't have a problem with that. Though resellers have to be aware that they themselves have to offer support to their customers not myself.  I will only offer support to the reseller directly.

Now the "terms" are out of the way.. All the simms are tested for at least a hour before I sell them. So resellers  are not buying "untested" stock from me.  They are all tested in my Atari STE machine (which is boosted to 32mhz to speed up testing somewhat) and are all manufactured by myself personally. 

I am offering a pack of 40 simms for £230 (at the time of typing) Which is a saving of £5 per set of 4. (Currently one set retails for £28).  It is the best value I can do as these do cost a lot to produce and test at least in such low production volumes.

As I manufacture these myself, it will take some time to build up a stock of them, but I hope there will be a lot more in stock over the next few weeks.


Tuesday, 20 June 2017


Not a huge update. Though I noticed that after about loop 60 GB6 would crash :(  It took ages to track down this issue!

Turns out the HiSoft Basic "WINDOW READ" function somehow crashed after 1,000 calls.  This was a function to convert a Window ID, to a AES ID.  I have no idea why, but something screws up after 1,000 calls and causes GB6 to bomb out to the desktop

Thankfully after some investigation, I found a OS call which did the same (and more in fact) so the problem was finally fixed :)

I had to test using STEEM on fast forward (which was going for some hours!) Though rather than crashing at loop 60, I got it to well over the figure.  This probably equates to running all week on a stock ST, so good enough for me :)


Monday, 19 June 2017


I mentioned in THIS post about my new production of 30 pin simms. Now I am finally getting to build them up and test them on the machine above.

I hacked up my previous test machine to test the SIPP version of the simms. Which means I was a machine down for testing actual simms.. Anyway..

As my prototype booster machine wasn't doing anything lately, I decided to use that one. This STE had a bodged in V1.5 booster and clocked at 32MHz.  Later this developed into the V1 STE booster.

This machine also has the new black DUAL TOS boards in case anyone is wondering what that board is (as mostly they have been blue). 

Quick eye people will wonder whats going on with the blitter. Well , I brought a huge stock of blitters a couple years ago and tested them all on that machine.  I had to hack in a ZIF test socket as the normal PLCC sockets would have likely broken. The ZIF socket was actually a couple mm to larger for the STE pads, so was some serious bending and bodgery to get it to fit. Though it works, and I tested like 200 blitters on that machine :)

The SIPP's are already on sale in my store. I hope these normal simms will start to appear over the coming days :)


The "BAD DMA" - The Myth , The Legend, The lies.

The "Bad DMA" has been circulating around the Internet since the dawn of time.  Where the -38 is apparently the route of all evil and every STE that has one will have hard drive problems.  Well, that may be so, but the chip is far from faulty as many sites lead you into falsely believing.

I personally have spent near on 25 years debugging and fault finding equipment, not just Atari ST's. I can tell you that you should be reading my current research into the issues, not grandma's good old tech doc's from the 1950's.  If you happen to stumble on such a site, I urge you to not go there again and burn it into the eternal fires of hell for all eternity.

For those who are not technically minded, or just too darn lazy to read my research on it, let me explain it as simply as possible.  Designing a motherboard working in MHz ranges is very difficult.  Atari could only do so much with a 2 layer PCB and regardless of how well routed it may or may not be, there is going to be issues with noise on signals.  This is a very common problem in all electronics equipment.

Unfortunately the DMA chip is about as far away from the CPU as it could get. This means the noise on the address and databus is rather bad.  So our poor old DMA chip sees signals which are not really there and basically goes a bit mental.

Take an easy analogy of this. Take a bumpy road with a F1 car which has very little suspension. You are going to feel every little bump in the road.  Now go on the same road in an off-roader which has huge shock-absorbers and you will never feel the bumps at all.  So are we going to blame the F1 car or the bumpy road or the off-roader for being awesome in covering up the bumpy road?  Not easy is it! This is exactly the same with the DMA revision numbers.

Some DMA chips react to the bumpy roads more than others. So while we can blame the F1 car for being the worst car in the world.. well, its actually the road to blame.  Simply changing the car isn't really fixing the problem, just "bypassing it".  This is known by electronics engineers as a total bodge.

But "it works" I hear you cry... yes it does, for now.. a bodge is still a bodge regardless if it works or not.  An expensive bodge at that I might add with replacement DMA chips being hard to find costing £40+.  Of course swapping the -38 with another -38 will likely work as well.  Just grab one from an STF and you may find that works.  But there really isn't any point in changing the DMA unless it is actually faulty, in which case , screwing around trying to fix your hard drive problems likely blew it up.  In which case this article won't help you in the slightest :)

We can however try something simple which research by my readers has had very good results. This is simply change the CPU to a 68HC000 type.  This reduces the current pulled by the CPU and reduces all this "road noise" and increases stability a great deal.  Oh how simple awesome and easy that was!

But I hear you cry "It still hasn't solved my problem".. Well, I never said it would.  I said it solves this particular issue. I mean if your hard drive is faulty causing data corruption (it happens!) then changing the CPU and/or DMA isn't going to do a darn thing is it.

Even so, we can't blame every data corruption on a "bad DMA" as there can be multiple causes and all need to be ruled out.  Swapping the CPU is a very easy cheap fix to try and I would personally change the CPU regardless if you have "DMA issues" or not.

One thing which is still WIP, is that STE's with Motorola CPU's are likely to have "DMA issues". Whereas machines with a SGS / ST CPU may not.  I only have a limited number of STE's here, but that so far seems to be the pattern!

DMA research page.


Please considering buying the CPU from my store. As said in another post, while things might be cheaper "elsewhere", such places/people are not investing huge amounts of time into Atari ST projects.

Sunday, 18 June 2017


I have been having a lot of thoughts lately about various design issues with the STE booster. For the first part, a few months back I designed a GAL to Atmel adapter board. It never got built (just not had time). Though while the Atmel is just a huge GAL anyway (basically loads more IO ports) I was designing the next gen STE booster to have fast-ram. Though the best SRAM to use for this project was 3.3V.  So I was adding in IO translators to adapt 3.3V <> 5V.  Nothing really wrong there. Though it does add more cost in PCB space, IC's, soldering, testing etc, and I just didn't want to do that.

I know Xilinx is popular and a lot of people use it. It has inbuilt translators which make it ideal. So I installed the free webpack (all 20GB of it!!) and fiddled with the diagram editor. It was pretty straight forward. Actually looked like the Altera software I am using. Though I couldn't for the life of me work out how to assign pinouts to the diagram to actual IC.

After watching god knows how many videos, looking at various webpages I basically gave up.  Turns it it was hidden in a bunch of places and when I finally got the pin editor up, I couldn't work out how to assign pins.  Where later it turned out they are drag and drop.   It actually seems like nobody has even used the diagram part of the IDE so finding help to use it seems impossible. That is pretty much the problem with coding on the Atmel chip, just impossible to figure out easily how to do anything. In the end, I basically gave up with Xlinx IDE.  I just find it very annoying and frustrating to use :(

I also remember when I was programming  my CT60 a while ago, I couldn't get the Xlinx software to work on my main PC. I ended up installing the software on my old laptop which barely decides to boot up these days.  It seemed to work ok on that, really old hardware I guess. Though my main PC isn't that new either, but still a quadcore based machine. I can't remember what the issues were. I think the software couldn't find the programmer.

So I decided to go with the Altera MAX7000 series for the moment.  I already designed the IDE prototype with it. Though I would also like to try to get the STE booster powered by a Altera PLD. This means my Atmel code on all my previous boosters becomes useless as I will be working with logic chips in the Altera software.  So I am having to basically re-invent my own stuff again.

Why would I do that ? Well, as said in blog post somewhere, I am tired of trying to code stuff where I don't know if what I am doing is right, or my "design" simply doesn't work.  I mean don't get me wrong, I really like WinCupl and the Atmel PLD's. Though anything past basic IO stuff becomes a nightmare to figure out.  Atmel have been helpful in answering my questions. Though often its waiting a day or 2 for a reply. Then the "conversation" can go on for months.. Its just not practical to continue like that. I also have the same feeling with the xlinx stuff.

Though the Altera software, I just started using and got along with it just fine.  I mean, I wanted to assign my pins, so I select pin assignments from then menu, what could be easier ?! Saved me 2+ hours of looking on various sites for answers on how to do basic things.

People may think I am mad, though I just prefer to draw circuits than code stuff.  I mean its like trying to write a book in ancient Egyptian when you don't have any sort of reference book on it all. Its just madness to try.

Of course, I never used Altera before, but I could just start designing easily and generally just get on with it.  Also the circuits I can design in my logic simulator software which I have been using for years. Design and debug, then just copy the circuit over to Altera and program the chip.  I mean its a lot easier than fighting with code and syntax of it all.   I just feel the Altera is the right move for me to make. So this new PCB is the first step in that direction.

I should be able to translate my previous booster code back over to a schematic in the Altera software. Then see how it behaves in the STE booster board.  Once I am happy, then I will continue work on the fast-ram side of things as I can route everything though the Altera chip :)

Saturday, 17 June 2017


UBE ( Universal Bad-ass Equipment ) Video Switch by Urban Jonsson.

While my blog was aimed at my own personal progress on various hardware items, I felt this video adapter deserved some love on my blog as it is somewhat unknown still and I feel a lot of people will find this adapter very useful.

This well built compact PCB plugs into the ST/F/E video port and outputs to a VGA connector so you can plug it into monitors which will accept the ST's video resolutions.

It has 2 selector switches on the side. One to select HIGH RES mode on/off. The other switch to select audio/video on the yellow RCA jack.

My TV did not much like the ST's videos mode much so I wasn't able to test low res modes. Though high res worked resonbally well and gave a nice monocrome output.  My digicam for some reason made the grey background look blue, but its actually grey! So neither my TV or digicam really does the UBE Switch much justice :(

The board also holds 3 trimmer resistors to alter the RGB levels. One thing which annoys most people is the lack of adjustment for overall "brightness". Where people normally end up in the situation of "to dim" or "to bright". Well this kit has the option for everyone to set it themselves! So win-win everyone is happy!

Overall the board is very neat and mine came assembled, and the soldering is really good quality as well. I really like the compact design and also the connects are ancored into the PCB properly to provide strain releif. So none of this risk of connectors comming loose and ripping tracks off like most boards seems to trend as these days. So geek points there for quality and attention to detial!

Urban has published the board under Github as a open source project. Though if he gets enough interest them he may consider selling kits or fully assembled boards.



Thursday, 15 June 2017

SR98 PSU gets more love

These SR98 PSU's are the most common that I have seen in the UK, the "trusty" SR98.  Well these PSU's from my observations have been failing for over 10 years now and I have a stack of about 50 of them which fail to power a STE for very long before they "die" totally.  

The electrolytics used were really cheap-ass ones and probably were not very good from new either. Problem for one is the heatsink on the right side being reaching 60c and above. Those electrolytics are being cooked by it reducing their life. People probably remember the "pea rectifier" being bad for overheating and bulging and basically exploding.  Its was well known back in the day, ST format might have even mentioned it in a guide, can't remember now.

Of course its unfair to slate Mitsumi for their cheap work. I mean the Atari ST was "built to a price" and "cheap as possible" to get as many machines into the publics hands as possible.  So thumbs up from that point.  There is only so much you can do "to a price" and they have lasted around 20 years, so can't really complain. Don't get me wrong, I really like the SR98. It was likely pretty awesome when it was new! I don't think anyone could have seen these machines being used 30+ years later and these PSU's are mostly still chugging away out there somewhere.

But it doesn't stop there.  While regulation can be made a lot better by using quality capacitors, I have also found changing the output diode also helps with regulation and also efficiency slightly!  I chose the lowest voltage drop diodes I could find under a 2amp load to try and keep the "heat" down on the heatsink.  As the heat warms up the capacitors a lot and one of the reasons the capacitors fail on these PSU's than maybe other brands of PSU.

I also went for a fast diode in terms of efficiency and regulation. I did not expect such a huge increase in regulation, though p-p was 0.5volts and dropped to 0.2volts after the new diode was fitted.  So this cheap-ass PSU can be restored better than new and with the mods can be made into a pretty awesome bit of kit!

The SR98 can be brought back to better than new with one of my SR98 RECAP KITS. I Also sell complete refurbished SR98's (and sometimes DVE PSU's) in my store which will include the new diode in later batches.

There are other mods on my website to improve regulation and general service tips.  For one, most of the PSU switches have horrid cracking, arcing, sparking sounds after a lot of use. I would recommend changing the switch if thats the case.




Tuesday, 13 June 2017


Myself being a hardware developer, I have always been sceptical about programs like the "Marpet RAM test" software along with the Atari diagnostic cartridge in finding faults.  I always have suspected faults (bad RAM) where no software would ever seem to report such errors.  These errors were basically impossible to track down and bugged me for a long long time.

I made a plea for someone to write a good fast RAM tester program and  Christian Zietz of CHZ-Soft came to the rescue and created YAART aka  "Yet Another Atari RAM Test".

Don't let this innocent sounding name fool you! It is by far the best RAM test software I have used and really gets down to business in tracing faults!  These days I couldn't live without it!

A quote from the website..

"The storage test programs available so far for the ST disrupt that they are usually very simple knitted. Obviously, you will find obvious problems with the RAM, but not subtle errors that occur only after many passages or with certain test patterns. For the PC, there are Memtest86 software, whose test algorithms have been specially optimized to find such errors.

I have now decided to implement some of these algorithms in a test program for the Atari. YAART ( Yet Another Atari RAM Test ) was developed. From the test depth I think it is already better than many other RAM test programs for Atari TOS.

YAART is available in two versions: YAART.TOS is intended exclusively for (mega-) ST (E) computers, but it can also test memory that is already occupied by the operating system or other programs. YAARTTT.TOS, on the other hand, tests only unoccupied memory, but runs on all Atari-compatible computers (eg TT and Falcon) and tests TT-RAM as well as ST-RAM."

I have being using it for some months now and it really does find errors which no other RAM tester program has even been able to find.  It's not often I get excited about such things, but YAART has to be one of the top software essentials to have!  

So HUGE THANKS to Christian for creating this fantastic program!


Monday, 12 June 2017

PSU batch completed

PSU's finally in my store.  There are about 5 PCB's left which are only half populated, but I basically ran out of bits :)  I do plan to finish these but I have spent so much time building these up over the past months that I need a break now from them. 

I also have a lot of other kits which need re-stocking in my store. SoI will be concentrating on those over the next months.

I dare say this PSU batch will be the last one for a while and likley won't be another batch until mid-next year sometime. 



Sunday, 11 June 2017


This board was designed last year. A couple was sent out to some beta testers, but I never heard back from them :(  So while I had a falcon to hand with a socketed RTC IC, I decided to try the module out myself. After soldering and a bodge edit, it worked just fine :)

This RTC IC is basically the same as the Falcon one, only this uses a external battery.  This way, it is easy to change the battery than having to worry about de-soldering the NVRAM in a few years time.

The module itself is a tiny fraction higher than the original NVRAM chip and should fit under the metal shielding as normal (though I have not tested that it will).

I have fixed some issues with the PCB and currently the next prototype is on order :)

Saturday, 10 June 2017


These are one of my original upgrades to upgrade STFM's to 4MB via a 72pin simm.

This upgrade is on sale for £25 (from £35) as it is now discontinued. The replacement is the MMU style upgrade my 4MB MMU KIT. This one is more expensive, but is smaller and fits probably all ST/F/M machines. It made no sense to stock both upgrades anymore. 

The 4MB simm kit as shown also only fits  C070789 Style motherboards. Where there is normally 2 or 4 banks of DRAM under the PSU.  This is what I call the best revision board to have and most of my kits were designed to fit it. unfortunately, with so many motherboard revisions it's mostly other types people have :-\

So while this kit is very cheap and one of my classic upgrades, There is no use in stocking them anymore.  Of course, if anyone has the "good style" of the board as I call it, then this upgrade is a steal for anyone wanting a cheap 4MB RAM upgrade for their STFM!



Friday, 9 June 2017


I have put in a order for the next batch of these Falcon Buffer Boards.  The first batch of 10 I did sold faster than I thought!  So its left them out of stock for a while now.  Several people have emailed me over the past weeks wanting to know when they will be back in stock, and they will be soon! check my store every week , they will appear sometime over the next few weeks!

My buffer board replaces any other/older boards/hacks which may be in the Falcon already.  There are so many "versions" of this mod its unreal. Though I designed this board to clean the clock lines up and buffer them while reducing ringing in the signals.

The problem with the Falcon is the source of the 16MHz clock came from a single source which wasn't really strong enough to drive everything which was connected to it.  Atari split this clock line 3 ways and added some small resistors (which is a good idea). Though unfortunately, this resulted in "back ringing" on the signals where noise on one line would couple to noise from another. With such low resistor values and various lengths of tracks running all over the place, it basically turned into a mess.  All buffer boards aim to buffer these 3 signals but in multiple ways, where some could actually make things worse!  

Some (or most) buffer the signals with a small buffer IC.  This is great, but the signals still had bad ringing and only "better" buffer mods aimed to reduce this,  mostly C-lab and Steinberg etc.  I had not heard of any Falcons having this mod, so not sure what the outcome was. 

In anycase, I started with a buffer IC and added in resistors to reducing the ringing on the inputs and outputs of the clock lines.  Each resistor was chosen for the best "compromise" between voltage levels and noise levels (both are conflicting requirements unfortunately) on each signal patch. This way all 3 clock lines are driven separately and have the buffer resistors to reduce the ringing which could cause "double clock pulses" and cause glitches in some parts of the Falcons DMA circuit.

These boards offer a low cost compact solution to solving the noise on the clock lines and have solved a lot of various issues people have been having. 




These small boards help to reduce the "noise" on the STE's DAC IC's by improving stability and regulation to the internal "ladder" network. 

I originally made a small batch of these a while ago and people came back saying it improved or eliminated their audio problems.  While the audio path can suffer from noise in various parts of the circuit, this board only solves the noise generated in the DAC IC itself. 

Also please note if you are looking for the best audio output then you should use one of my low noise PSUs which have much better regulation than the original ST PSU.




Thursday, 8 June 2017


The next run of the STE DUAL TOS boards is in motion.  These will replace the previous blue boards.  These are a fraction smaller but as basically the same as the previous blue boards.

These boards hold TOS1.62 and TOS2.06 and are available in most languages. Selection is done by a simply jumper link or a toggle switch (not supplied).

The only real change is the TOS select jumpers have gone from 3 pins to 2 pins. Also now there is a pull up resistor. So when the jumper is "missing" it will default to the upper TOS bank in the ROM. Connecting the 2 pads will select the lower bank of the ROM.



Wednesday, 7 June 2017


Just a quick update on the Falcon Clock Buffer Patch boards.  I have started building up another 20 of these and will be in my store once assembled and tested.


Monday, 5 June 2017

ST/F/M V1.5 16MHz booster

This simple booster can fit in just about any ST/F/M machine and gives a 16MHz boost and can even work with Fast-ROMs giving 16MHz Fast-ROM access.

Results are impressive from such as small booster.

While its big brother the V2 BOOSTER offers the addition of TOS206 as well, it is at the end of its production life now and the V1.5 is almost identical speed wise and fits a lot more machines.

The V1.5 booster also is compatible with the blitter and gives a huge speed boost again when running in 16MHz modes.

The V1.5 BOOSTER is supplied assembled and tested.  It also needs Fast-roms (100ns or faster) to make use of the Fast-TOS feature.

I offer various ROM kits in my store to fit various ST/F/M machines.  The stock ROM's in the Atari ST's are generally not fast enough (normally 120ns - 250ns ) and are too slow.  Of course, the V1.5 BOOSTER will also work without the Fast-Roms , but performance will be degraded.




Some time ago in my DMA pages I wrote about a hard drive testing program that I used to test the DMA chips with drives such as ultrasatan.This program was custom wrote for me by ultrasatan's creator Jookie!

The program wasn't intended to be released into the wild, but with Jookies permission, he is fine with my releasing it as it may well help others.  This has only been tested on a STE with ultrasatan!

The program can do a loop test, which will loop though write-read-verify constantly. It will also allow each sector to be written to up to 255 times each pass.  Note that for "flash storage" 255 writes per sector is a lot, so be warned.   Generally if nothing flags up as a error, then likely everything is fine.

I also requested a second test which will write a known string to each sector. The idea here is that the SD card will be written to with known data, then the SD card can be placed into a SD reader on the PC, and using a suitable sector viewer program, you can read each sector and see if it looks like this..

The first few bytes of the sector will list the sector number in this case 00 00. The same data will be repeated but will show 00 01  etc etc.  The ACSI pattern repeats over and over each sector.

My findings (in a nut shell) were that as above, there was no WRITE READ failures at all. Believe me when I say I tried for hours to see if anything would break. It never did.  The only time I saw a error was when  my scope probe slipped and shorted out 2 datalines on the DMA, causing errors. So I know the software works as intended ;)

Interesting thing is, as soon as I go to desktop and save desktop.inf, or creator a couple of folders, the drive gets trashed totally which is the fault most people see with drive corruption.  So is the DMA faulty or not ? well actually not. DMA "failure" is nothing more than "combinational noise" on the bus which is what I have been saying over and over for the past few years now.

You can literally "break" the DMA circuit many ways, bad PSU causing noise on everything, To unstable RAM or even the brand of ROM's used.   My findings also show that machines with a Motorola CPU are almost guaranteed to fail, and while more testing needs doing with the ST brand CPU, machines don't seem to fail at all.

With so many brands of RAM, ROM, CPU, PSU, motherboard revisions etc, it has created a huge mash up of hardware to debug over many many machines involving several people who have also confirmed my findings already.

I have said for a long time that there have been many ways to solve this issue, though one single solution has never worked for everyone as literally everyone's machine has different hardware combos.  Just basic stuff such as RAM and ROM is enough to break the DMA on some machines. The list is endless.  Everything contributes to noise on the bus. Some machines suffer more than others. So while swapping the PSU may work for someone, it may not work for someone else.

So far my research has found the CPU itself is one of the root causes.  Simply changing the CPU with a 68HC000 has generally proven to solve problems on all the machines tested so far.

Of course there may be machines which have really bad noise where further action may be needed to solve the issues.  Or the DMA IC might genuinely be busted. Though this program by jookie will easily let people know if there is a actual DMA issue or not.  Of course this is assuming the hard drive is known good to start with as the drive itself could be at fault, not the STE.

So HUGE THANKS to Jookie for creating this really useful diagnostic tool for me!

For more information see my website below.


68HC000 CPU

Jookies website