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Hmm, this should not work. I don´t know the exact technology behind the PBI bios, Jon can answer this, I´m sure. But Sys-Check actually can only emulate OS-ROMs in the address space $C000-$FFFF. More and/or other things are possible, but require change of the logic and/or PCB. Jurgen

Just de-install all additional parts and connect the pin 1 of each 41256 chip together and then to ground or +5V, whatever you like. Then it´s a standard 130 XE again. Watch out, some methods of making a 320 XE includes trace cutting of PB7, mostly below the PIA. After de-installation of all additional parts check pass from pin 17 (PIA) to pin 6 (MMU). Jurgen

No, this wouldn´t work. The ATR function of the SiDE only works in junction with the PBI BIOS of the Ultimate 1MB. The U1MB is mandatory for using these special mode of SiDE devices. Standard usage is possible like with any other memory expansion. Jurgen

Thanks for the screenshots. I will try to setup an identical 600XL to analyze this behavior. Could take some time, please be patient. Jurgen

This issue couldn´t be verified by me. I´ve tested an ABBUC-member owned 600XL (with 64 KB base memory) and a selfmade SRAM 512K expansion with Hias´ GAL code and it works with Sys-Check V2.1 (the older version w/o memory expansion) without any issue. Can´t imagine or explain why this souldn´t work together. Your description sounds like an issue with PB7. Try it out using Satantronic´s XRAM V0.21 memory test program and sent a screenshot, please. Jurgen

Hi folks, I got a hint about the Sys-Check V2.2 manual I want to share. On page 12 (german and english version) I suggest not to use the external Sys-Check memory expansion when the computer is a XE model and has already a memory-expansion built-in. This information is outdated. During tests with the beta-testers there were some problems at the XE machines due to the typical bad XE timing, but I could fix that. All shipped versions have already the actual logics in their GALs programmed. So this info will be deleted from the manual. Everybody could use Sys-Check also without any issue if the computer has already an internal memory expansion. The only combination not working is Sys-Check together with the TurboFreezer AND both memory-expansions enabled. This will produce memory failures (in the extended memory area). Reason is simple: Both expansions uses the same way to get access to the addressbus: Draining REF (refresh signal) to low. Jurgen

Unfortunately there´s no way to realize that in a safe way. The only way working with all carts is power-cycling, but this could have side-effects I don´t want to be liable for. The cartridge connector doesn´t have a RESET signal nor any other signal which may be used for a defined RESET. Of course something like a protocol-driven access could be perform a RESET, but using this way all carts must support this. Independent from Lenore´s fine work I suggest a different way. I patched the standard XL OS (rev.2) in such way, that holding down SELECT performs a coldstart. When holding down OPTION, not only BASIC is disabled, additional a LDA #0 STA $D500 is performed. This enables (if disabled) and set bank 0 from nearly all switchable carts and works fine for the AtariMax and similar - not depending if the cart is addressline or dataline driven (in bankwitching). Such a patched OS should work fine. I never published that, because it´s only a silly simple patch. Most users like to use the Hias´ Highspeed-SIO patch, this one enables cold-start with holding SHIFT. Maybe I can convince Hias to add this little feature in his HS-patch. Jurgen

Cool... happy end

Just for clarification... it´s not really only a simple switch - This wouldn´t be secure for modern carts. A GAL16V8 is used, the switch only toggles one input of the GAL. The logic realizes complete invisibility for the cart which is not active. All cartridge controlling signals (RD4, RD5, S4, S5 and CCTL) are switched by logic. Output RD4 and RD5 is buffered using transistors. So it´s a safe thing.

Sure, it will work. This type of track display uses STEP and DIR signal of FDC and resets if TRACK0 is active low. It will work with any drive at any system and can count up to 99

Hi Wilheim, I have one version "B" board left. New boards (both versions) are ready in 3-4 weeks. Please PN me, if you want one. Jurgen

Hi all, the archive in the attachment of this post includes the installation instructions in polish language. Many, many thanks to Voy for the translation! Jurgen BitWriter Replica 1050.zip

A lot of good tips are already written, here my 2 cents ... when the drive makes to typical initialization (drive motor starts spinning, head will be move for- and backward, after a few seconds the drive motors stops and the drive activity LED will go off) then CPU, RAM and ROM at the mainboard seems to be O.K. An error 138 indicates that the computer can´t communicate with the 1050. Did you try all drive numbers from D1: to D4: to access your 1050? Maybe the drive select switches at the rear are defect of the 6532 RIOT. This chip is something like "glue" for the whole drive, it controls the whole SIO part, drive motor on/off, step motor enable one step and direction and a lot of other things. Make sure during test that no other SIO device is responding to D1: ... D4: ! Check pin 8 and 9 of the 6532 with a meter. The drive select switch with the white tab is connected to pin 8, the black one to pin 9 (when I´m remember right, otherwise the opposite...). When you change the position, voltage must be change from high (something by +5 volt) to low (0v) and vice versa. If this works for both switches, the switches are not an issue. From my experience repairing the 1050s it´s mostly the darlington transistor array 3086 (U1). This array will go defect sometimes when SIO cables are plugged during the computer and/or other SIO peripherals are switched on. If you can, first check the 6532, it´s easy to change because it´s in a socket. Then, if this doesn´t help, exchange U1 (3086). Sometimes it´s hard to get this one, at least Best Electronics have this chip. Good luck, Jurgen

I have a working 5200 and can lend it to Simius. Will PN him. Jurgen

The FPGA PBI board made my Wolfram Fischer (mega-hz) is a universal, multiple-use development expansion for the XL series. It has some parts already onboard like SRAM, NV-RAM (EEPROM), some 7-segment displays, switches, push buttons and so on. You need an Altera USB Byteblaster to program the FPGA chip. And, of course, VHDL knowledge is required. This is not a "ready-to-use" thing, the target audience is more ambitious hardware tinkerer. Such a FPGA solution is extremly powerful, you could integrate the Turbo Freezer and more expansions in one of these. As already existing with VBXE and others, complete chips can be emulated. The possibilities are nearly endless...

Yes, the same way could be used for the 1200XL keyboard. But in the most times the main problem with the 1200XL keyboard is the "handover" from the PCB´s gold plated contacts to the mylar. Most times it´s enough to repaint the contact traces of the mylar at this "handover" point. Then remove the black coal plating, clean the contacts with isopropanyl alcohol. Finally I use one or two small stripes of duct tape to rise the pressure at this "handover" point (sorry.. when I get my own 1200XL, I can shot some pictures, it´s easier to understand). Maybe here´s a thread anybody else shown it already... The round dots I also always repaint. There´s no problem with the thickness, even if you repaint it twice. The clearance between single key mechanism and the mylar is wide enough.

Ehm... you can´t use the MMU (CO61618) built in the 600XL, 800XL, 800XE or 130XE in the XEGS, they have different signals at some pins. XEGS (C101686) and 1200XL (CO60609) have a special MMU, all other systems have the same.

Yes, it´s one of the typical NTSC base frequencies, but the Atari will still work with that. Only the GTIA won´t produce correct PAL color clocks, but nothing can be damaged, you get just a b/w picture. The voltage level directly measured at the crystal is very low, mostly between 0.8 and 1.2 volts. This is normal and no indicator for a defect. FREDDIE or MMU are the first things I would try also. The MMU can be exchanged by a 16V8 GAL. The GAL code incl. JEDEC-file in the attachment XEGS_MMU_GAL_Replacement.zip

The computer will start with the wrong crystal, but you won´t get any colour or wrong colours. But for testing it´s ok, also you can use a 14,318 MHz crystal, which is common. If you doesn´t need anything from Bradley (BEST Electronics) sent me a PN, I will put a crystal in a letter and sent it to you. Have some dozens of them Jurgen

That´s a good idea, too. Ok, looking at the scope pictures the signals you show are good. CPU doesn´t deadlock, so CPU, major chips and O.S. ROM seems to be fine. Makes it not easier... In the attachment you will find the XE System schematics drawn by Jerzy (don´t know if you have them already). Examine every signal at freddie related to the schematics. Also MMU. When you´re lucky, you wil find a missing or bad (high level below 2,5 volts or something like that) signal. Good luck, Jurgen xesys.zip

I think, nobody has them. BEST Electronics and myAtari (B&C) haven´t any mylar for that keyboard... But you can fix it! All you need is some silver conductive paint and smooth hands. I suggest the following steps: 1. Use a very soft rubber (special for stencil-art for example) and clean all traces. You can remove a lot of the black, dirty parts from the traces. 2. Clean the whole mylar foil with hand-warm water and some dish liquid 3. Let it dry for 30 minutes 4. Use a stapler and mount the unfolded mylar to some soft wood or rubber or what you have and which is usable for staples. Of course use places for the staples at the outer corners of the mylar, where no traces etc. are. Without this step you will get mad for sure... 5. Take a ruler, a very fine paintbrush and repaint all traces with the silver conductive paint. Start at the top, repaint all traces horizontally, let it dry 10 minutes, then all tarces diagonally, dry, then vertically. This way prevent you from blur out the conductive paint. You will need 2-3 hours for the job. But in over 90% all cases I´ve done that the mylar is working again for years... Jurgen PS: Don´t be so lazy and fix only the traces you might see a broken trace... even if you fix it with success, a few months later another key(s) won´t work. I promise that...

Got my three Excel magazines last saturday. Superb quality, nice graphics, good text - a pleasure to read. Also my wife - not a real Atari nerd - likes to read them. Thumps up! Hope, issue #4 will come one day

IMHO this is a failed assumption. The POKEY chip is the one and only in the Atari 8-Bit chipset which has two (!) chip-select signals. Atari would have advisedly the goal to enable more than one POKEY in a system or cabinet. And CPU power isn´t the issue here.

I´m also interested. One hint for a possible mass production version: It should be better to place the GTIA (the real one, which must be placed on the new PCB) at the top of the PCB. Simple reason: This arrangement or parts will not work well in a XL system (800 XL, 600 XL) when all may be full socketed. But when the socket for GTIA is at the top of the PCB, it will fit in all systems (XL, XE, XEG). Jurgen

Hi, the pins 1 and 2 of that connector are only constant power for a IR LED used for the light barrier. Pin 2 is ground. Pin 3 and 4 (4 is also ground) is the photo detection sensor. The output is stabilized by using an NOR-gate from U11. The simplest way: Solder a switch (with 3 terminals & 2 positions) to J11. The middle terminal of that switch connected to pin 3, the other terminals to pin 1 and 2. This way will change the pin 3 voltages level between high (+5 volts) and low (ground). In one way all writes are allowed, in the other not. And it´s reversible, no damage to the drive mechanic needed. Jurgen