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Hi, would also take one cart. Thanx, Jurgen

- I´m just a hobby tinkerer. My goal was not to earn my monthly costs though some hardware offers. The only requirement - demanded by my wife - is that the whole Atari hobby doesn´t had to have influence on the family budget. So all prices are calculated of material costs, Paypal costs, tooling costs (solder tin, desoldering wick, some tools needed etc.pp.). And when there are some Euros left, they are invested in the family or new ideas

Didn´t understand the intention of this. The price for V4.3 is 3 Euros higher, because I must order two PCBs and a little bit more mechanical stuff. Because the older V4.2 works only well in the XE series, I lower the price down to 20 Euros for that version. If the actual stock of V4.2 is empty, I wouldn´t make V4.2 any longer.

As long somebody wants to have sometime one of them three, I will offer them. Maybe not in stock at all times, but the lead times are mostly less than one month. Dependent on my wife when she grants spare time for Atari

Hi! Due some feedback to one of my oldest projects "Sys-Check V2.2" I create two new versions of Sys-Check. They´re simply called Sys-Check V2.2 XL and Sys-Check V2.2 XE Technically there´s no difference to the standard version. The standard version is also offered furthermore. All new versions of the firmware will work on all Sys-Check versions and revisions like ever promised. While Sys-Check V2.2 "Standard" remains usable for all Atari XL computers (except 1200XL) and all XE computers with ECI-Port, the new versions are specialised for XL or XE models only. Both new solutions have distance bolts to have the PCB secured for continuous usage - a lot of users of Sys-Check reported me they never use it for diagnostics, but main time for external memory expansion or a different O.S. like for SIO2BT and others. The reasons for these new versions are: Some XL owner wished to have a Sys-Check version which is not upright assembled to easier access the switches Some XL users want to have the possibility to add a second PBI device, for example a harddisk-interface Some XE users need the possibility to connect a PBI device to your XE computer Here are the pictures of Sys-Check V2.2 XL The PBI connector at the end of the PCB is a 1:1 connection to the computer´s PBI. You can plug, for example, the Turbo Freezer 2011 behind Sys-Check XL and it will work. Of course you got problems when you enable OLD-OS or the memory expansion at the Turbo Freezer device AND also enable OS-ROM external support by Sys-Check and/or the memory expansion by Sys-Check. Only one external OS or one external memory expansion should be enabled. And some pictures of Sys-Check V2.2 XE The XE version has a PBI connector, which is mostly 1:1 compatible to the XL PBI. There are four signals, which aren´t existing at the XE ECI connector: RAS, CAS, EXTENB and RDY (Ready). These signals have a 6k8 pull-up resistor each to gain maximum compatibility. The most actual PBI devices don´t need one of these four signals and run fine. I found only the older Turbo Freezer II with DRAM memory expansion, which won´t run, because it needs RAS for the memory expansion part. But maybe more old PBI devices won´t run. This limitation always exists on any XE ECI to PBI adapters. I will assemble a few units of each version in the next 2-3 weeks. Watch out my most time each week updated info PDF found in this post Jurgen

Good news I´ve made a new version (V4.3) of my 512 KB memory expansion composed of two PCBs like the way VBXE XL does it - thanks again to FlashJazzCart for the hint! I´ve tested this version successfully in all 600XL and 800XL versions I own. All five keyboard variants shown in the thread here fits well. Only two, or better, three things must be observed: When used with the UAV plugin version (Atari 800 XL mainboard), then the UAV must be put onto two sockets instead of one to give space for the memory expansion. Of course I´ve tested this combination with all keyboards mentioned above and it fits well When installed in an Atari 600XL, the modulator must be removed At some keyboards black stripes of rubber are glued on the keyboard´s PCB. In some variants they must be removed. Some pictures installed in an Atari 800XL: And installed in an Atari 600XL: I will made some pieces of the new version ready in the next weeks. Watch out my info PDF as mentioned in this thread (see post #1, at the end of the post) Jurgen

Hmm, when there´s a trace damaged or broken the issues should happen immediately. When there´s bad RAM after 10-30 seconds, but the DRAM chips theirself work fine, any part of the DRAM timing circuit must be defect. Both address decoder 74LS158, the 74LS375 and 74LS51 would be the first parts I would keep an eye to it.

Just to clarify, I already email´d with Jon regarding this... my stereo enhancement can be connected to the U1MB "M1" pin and then Jon´s BIOS will detect a stereo solution and enable/disable it using the BIOS. But this is only possible with performing a RESET. My idea was, if I made a new version, to switch the stereo/mono mode by keyboard using a special, until today unused combination of keys like CTRL, SHIFT and "S" together (for example).

I made a lot of thoughts about this idea already in 2011, when I create the first version of the stereo enhancement (this time with THT parts and twice as big PCB..). But until today I didn´t found a working solution. To realize this feature, any kind of logic must be able to differ between stereo- and non-stereo applications. My first idea was to use a flip-flop circuit for the mono/stereo switch-input. As long no access to $D21x happens (where the 2nd POKEY is located), the "mono-mode" is active. With the first write access to $D210-$D21F the stereo-mode will be activated. Sounds goods! But... the O.S. writes zeros in the initialization reset subroutine to all I/O addresses over the complete page ($D2xx), so this idea was nice, but useless. So I add another TTL chip (74_123) and use the RESET line for a delay. When RESET goes low, a few milliseconds are waited and a flag was set. Only when this flag was true, the detection of a write access to $D21x is valid. Works fine for the O.S. coldstart, but only for this - or the RESET key is pressed. After trying out how it works I found out, that a lot of games, demos and other stuff just use the mirror addresses for POKEY, too! Even the mono-only, old software. Several games (I didn´t wrote down their names, it was a lot of years ago) access the standard POKEY not using the primary origin at $D200-$D20F, they write to or read from $D280-$D28F or $D230-$D23F or other. This works fine, because the MMU and the 74LS138 I/O selector only splits in pages (256 bytes each) and the whole address space of each I/O chip is mirrored, but makes such a detection much harder that needed. Regarding the need of more chips (ok.. today I would combine them all in one GAL) I dropped this idea, the result wasn´t very satisfying. If anybody has more ideas, you´re welcome! Maybe my next version of the stereo enhancement will be also have an acceptable solution, I planned to simply use the keyboard to switch mono/stereo mode. Any special combination like CONTROL, SHIFT and CAPS for example toggles the mode. Or two different combinations for on/off, ... Jurgen

Absolutely right. But when talking about an Atari 400 or 800, it´s more important to replace the 7805 regulator. This one is only specified for 1A max. und typically loaded (Atari 800 with 3x 16 KB RAM cartridges) with approx 800 mA. The 7812 won´t get very warm, but the 7805 gets hot. The TRACO ones are good, but very expensive. Some chinese seller at eBay have step-down converters with 1,5A max. load and something like the LM2576 series on a little small PCB, which has compatible pins for direct replacement of a 7805.

By default no issues should be happen. But I can imagine, some rare programs for example expect that the screen´s memory or display list at the 48K memtop ($BCxx up to $BFFF). When such a program don´t use a XIO call (as spoken in Atari-Basic: GRAPHICS x) it will nothing happens on the screen. But I think this chance is less than winning in a lotto game... on the other hand, I personally don´t know about software specially use this 4K more of RAM.

Hmm, when you want to go ahead with this, it´s better to remove the ANTIC´s socket and solder the ANTIC directly in. In the U.S. a new ANTIC - if ever needed - is easy and cheap to get. I must say, I think I´ve miscalculated the fit. I´ve tested it in three different 800XL of my personal stock, it works fine (with closed cases). Only the one type of keyboard I already mentioned makes trouble. Maybe the PAL cases are mostly the ones which my expansion fits well in and NTSC not (only a suggestion). There are over 7 different case & mainboard & keyboard variants I know of, of course I can´t test them all. So I make a new version last week, PCBs are already on their way to me. I use the way FJC suggested and like the VBXE "XL version" does it, too. This new model should fit really better in all 800XL and the 600XL, too. I will test it next week and report. If the new solution works better, I will offer the 3 people reporting problems a solution we all can accept. The actual version works and fits fine in all XE variants and the XEGS, too. Jurgen

The picture you show is from the AtariMax APE package, when I´m right. APE itself runs only good with the SIO2PC-USB (which is also a SIO-2-1050 etc.). When I´m informed right, APE works in the actual version 3.0.13 with other SIO2PC-USB solutions, but not at full speed and some other issues. The ProSystem utility only supports the SIO2PC-USB made by AtariMax.

Yes! I´m not a really good gamer, some games I don´t understand and haven´t the effort to find it out by myself. So some manuals will bring back some old gems I hope

Thanks for correction - but my statement is also valid for these type of caps. When charged at the typical 5 or 12 volt low-voltages found in the computer of the 80s the aging effect on poly film, ceramic, MKS/MKP etc.pp. capacitors are extreme small.

No. This monitors have PAL-only TDAxxx chips for beam control etc. Also there are fixed oscillators onboard, so no variable frequencies possible.

This is a ceramic capacitor. At normal circumstances you don´t need to change ceramic caps. Most times they´re working fine or simply cause a short-circuit

Please use machine-head precision sockets. This will make Sophia fit perfect. Some of the XE mainboards have a really bad quality. My personal rule of thumb: Darker green color = better quality, more light = bad quality. Maybe other people have other experiences of course Desoldering is something special, even if you have skills in soldering, you should train on some other old PC cards for example. A good practice for Atari related stuff is desoldering sockets or ROM/EPROMs from old network cards (boot-ROM / socket for this) and VGA cards. Or any other old PCBs. If you haven´t a desoldering station or desoldering gun, take a good desoldering handpump or desoldering needles (something like this: https://www.ebay.co.uk/itm/192512943471). Also - maybe not everyone´s cup of tea - you can take a plier and cut off every pin, what will make the old GTIA unusable, but it´s defect. Then remove the rest of the pins, clear the holes with any simple desoldering pump easily and that´s it. Using this way it´s nearly impossible to make failure and damages to the PCB.

Hmm. Theoretically it should be possible to replace that IC with an ATMEL ATtiny or PIC micro-CPU. When running at 10 or 20 MHz with internal oscillator, no other external parts should be needed. A SOIC or SOP or TSOP package should fit fine on a DIL-14 adapter PCB. I´m full of projects... maybe anybody else has the time to figure out this... and actually BEST Electronics have them in stock for 5 USD.

48 KByte will be seen. This is because the ROM is always mirrored in $C000-$FFFF (with exception of the I/O area), not dependent if the ROM image needs 16K (XL/XE OS) or 10K (400/800 OS). A replacement GAL16V8 with different code would make this possible without changing any other parts or traces on the mainboard, but then no XL/XE OS can run with such a modified MMU. So it´s only an academic thing I think...

This switch is for selecting a different operating system. The chip above is the genuine XL O.S. ROM, but under these there´s an EPROM with any other operating system. The switch will toggle between them. Start the computer with switch in one of the both positions. If you got "MEMO PAD" without disk drive attached, then it´s an OLD-OS from thge 400/800 series. Maybe you got a special color or any other info... try it and sent a picture - the standard O.S. will show "READY" with blue background.

Hi, can anybody sent some pictures using this mylars with the screws for the Mitsumi keyboard? Actually I have no plan how to do it, maybe I´m brain-blocked only... Thanks!

Hi, reveiced also today my order. Thanks, Simius! Good quality, good fit, fine work. Jurgen

Such a solution can also end up in instability issues. The complete buss is connected to the ANTIC and some important clock signals, too. I would no recommend this, when you want a stable running system

Hmm, I test both 800XL mainboard variants ("standard" 5 chip and "rose" with freddie) and using all cases and mainboards I have the case will fit (with screws fasten on, of course). There´s one keyboard (I don´t know which version yet) with a metal beading - this combination is very tight and I personally used a file to remove the beading at the point where it touches the ANTIC (on the memory expansion PCB). Maybe there´s a combination I didn´t know of