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Yes. Must update the manual... In the attached ATR file are three little binary files: MOFF.COM to disable memory expansion, M512 to enable 512 KB RAMBO mode (default) and M256 to enable 256 KB Compy-Shop mode (with seperated ANTIC amd CPU access like 130 XE). SRAM_Memory_Expansion_Mode_Change.ATR

You should leave the internal 64 KB - my expansion "only" supports 512 KB port-B controlled expansion RAM, but no internal RAM.

Would be impossible due to the fact that only one SRAM chip with 4 megabit (512 KByte x 8 ) is found on the PCB

In this thread I list the atari part numbers in relation to the frequencies. Did you measure always 5.5v even if the pot is turned to the most left or most right position? Then there´s something wrong. You should get up to 12v at one end or nearly 0v at the other.

Did you check the color pot on the CPU card? Maybe you just need to turn it around to get the color back. If this doesn´t help, some hints: - Check if there are 12V attached to one pin of the color pot - Check voltage of "color pot output" at pin 17 of the GTIA - should be between 5.2 and 7.0 volts DC for correct colors - If this was an used system (bought from eBay etc.), check if the system crystal on the main board fits to the TV system (NTSC or PAL)

Don´t call me silly, but which chip you tried to look at pin 8? Maybe you were influenced by the "CPU" on this page, but this meaning the whole CPU board, not the 6502/6502C. pin 8 on both CPUs is +5 volts power. Pin 8 of Z302 (aka 74LS74) is only existing on the old CPU board variant with 6502 standard CPU, it´s the "PHI1" signal and has the frequency listed in the document. When key click appears, the O.S. must be running. So I would assume that the CPU is working fine. So it´s a display issue. The 400 has only RF output (antenna), here´s the first way to check if your TV really supports these old VHF channels. Some newer flatscreen TVs (if you use such) doesn´t support this old stuff any more. So make troubleshooting easier, remove the memory cartridge. After power-on you must now get a whole red/brown screen. Good luck, Jurgen

Wow. Looks very cool. Which ITX case you´re using?

Just a hint: There´s a 100R resistor in the lines from POKEY to SIO. So if you use a standard DMM, it might not "beep" for pass. Some DMM confirms a pass only when the resistance is below 30 ohms or so. Use resistor measurement, set DMM to <2k and then you should read something around 100R.

Hi, The A4 line is the minimum which MUST be connected to make the stereo board work fine. If you left the A4 input open, you got a floating input, which may cause in problems. In best case the POKEY one (the mono / single one) will be work normal, but it also can happen that the machine hungs up - that´s the behaviour when no POKEY is attached. Normal blue screen, but no READY or no boot sound (try to find Disk D1:). Without having SR connected, there´s also no feedback to the monitor jack Again - as explained in the manual: ALL POKEYs work fine with stereo mode. And, I never found a program, demo, game or something else which will NOT playing stereo effect (as they support stereo, of course!), even if the detection routine said "Mono". You can exchange the three POKEYs you have to find a better pair, where the detection works fine. This behavior affected ALL stereo upgrades, not only mine BR Jurgen

Hi, it take more time than expected, but now I´m ready Here´s the manual & instructions for the Turbo 1050 Replica. Installation Instructions Turbo 1050 Replica.pdf Please download the whole archive incl. pictures here. BR Jurgen

This doesn´t work it out. Of course I could make the PCB one cm (or so) less in depth, but then the both GALs with their sockets are too close to the ANTIC´s position, so that some keyboards prevent the complete 800XL case from closing correctly. I test this out with a model of my PCB using "Fimo" (I don´t know the english word, it´s a kind of play dough from my kids) in over 10 different 800XL systems, each 800XL case with all five keyboard variants. The result is THIS actual version V4.3, which fits in really ALL 800XL cases and keyboard variants. Took hours to investigate, but this time I didn´t want to repeat such a silly mistake. The one and only issue is the need to remove the RF modulator when it should fit in the 600XL - like also needed for VBXE. All XE and XEGS always work fine with both versions. Maybe a smaller PCB will be possible if I would solder the GAL chips direct on the PCB without sockets, but this is a no-go for me. All programmable chips (GALs, EPROMs, Flash) has to be in sockets for maintenance purposes.

IMHO the right cart is only initialised when there´s no left cart plugged in or the left cart is not flagged as runnable: When the left cart ("A") is started, a JMP is used - so there´s a never-come-back to the point where cart "B" (the right one) will be executed...

1st: I already mentioned this clearly in my announcement post 2nd: Nezgar already states, that there are fitting problems with the NTSC 800XL he own in this thread. All purchasers of the V4.2 who report issues got a free of charge exchange to the newer V4.3 version already.

Ok, then maybe one or more traces are broken. Take a magnifier and inspect every pad first. If you can´t see anything wrong, use a multimeter and check signal flow. Search for "schematics" and "atari xe", you will easily find the Jerzy schematic files.

As I wrote above the "Selfdemo" is one of them. Or the game "Yoomp" and others. But again: Most of the programs use the same detection routine, and this one not detect always "stereo" even when stereo is running fine and the stereoboard working. So best test is: use your ears

Are you sure that the monitor or TV used is able to display PAL well? Or do you use any kind of converter box between the Atari and your display? The 2nd picture looks like one of the dozens of converter boxes I´ve had in my hands, when they aren´t able to display NTSC well on my PAL equipment. Mostly they use all the same way (converting the analog S-Video or CVBS signal to a digital stream and then back to VGA analogue with upscaling) and when the upscaling is realized poor, then it looks exactly like the 2nd picture. If you own one, plug a NTSC GTIA into. You will get no color, but a b/w screen. This way to test if your solder job was good or not.

I don´t know it really. But what I can say... I let produce a few hundred pieces of the very special frequency of 14.18757 MHz with "standard" values (30 ppm, 16 pF). They work fine in every XE PAL system and more... So the typically 15-20 pF offered in the most stores should be fine.

The answer is simple: Analogue - The affected part at the internal circuits of GTIA are dependent on the input voltage of pin 17 (CADJ). As nearly all chips, there are tolerances. In the 70s, where GTIA & Co. was initially developed, these tolerances where huge in relation to modern times. Even the same manufacturer of GTIA and same datecode may result in slightly differences in color. Using NTSC this effect is more visible than using PAL.

Hi, found some Stereo test tool and demos in the attached ATR file. There´s a "Stereo Test Utility" by Raster included. Even is this tool detects no stereo mode, it tries to play stereo. That´s a behavior I mentioned in the manual already. Not all combinations of POKEYs will be detected by the "register test" as used in this tool, but the solution will work. In the ATR file there´s the "Selfdemo" by C.P.U., this one shows at startup a nice splash screen when Stereo is detected. Otherwise "Only Mono" will appear, but if your stereo board is fine, the demo plays in stereo. Best hearable at the "RAM Test". Without keyboard... hmm. Didn´t try it out, but maybe the PICODOS installation I used can be controlled by joystick. Otherwise you´ve to copy the selected files to a seperate DOS disk renamed as AUTORUN.SYS. This should be boot without any key press needed. When pressing "A" for audio test after loading the Stereo Test Tool a digitized voice and standard POKEY sound appears - first left, then right channel. Even if "no dual pokey found" is displayed. So that´s a good test. Good luck, Jurgen PS: The monitor jack output works normally, but only for left channel. Connect the "SR" pad from my stereoboard to pin 6 of the LM358, then also the right channel is hearable at the monitor jack (and RF modulator, too). Stereotest.zip

Hi all, all owners of the previous V4.2 version of my SRAM memory expansion got (or it´s in shipping already) a free exchange to the new V4.3 if they had fitting problems. All manuals and the info PDF file has been updated. Please use the V4.2 version only for XE computers and the XEGS. The new V4.3 version fits in all Atari computers incl. the 600XL. Check my info PDF (see post #1) for availability. Jurgen

Would confirm that. I´ve repaired a lot of PAL 400/800 in the last years, but all of them had the CPU board with 6502C CPU onboard. I´ve also see some NTSC 800 with the 6502C CPU board and unpopulated parts for the PAL burst frequency generator, but never the other way.

Thank you very much for sharing! I´ve killed one of my SIO2PC-USB during repair due a heavy short-circuit. So I´m very interested to get 2 pieces of them. Anyone able and willing to make two pieces for me? Of course the costs will be paid. PN welcome

THIS was amazing fast - today my cart was in the mailbox. Thanks, TMP!

Using your Sys-Check V2.2 standard edition: Remove the card edge connector and solder in (see the middle row of pins reserved for that) a standard 50 pin male IDC header. Now take a standard SCSI-1 50 pin cable, these are straight 1:1 connected. This should work when Incognito use the same pinout like the PBI at it´s IDC header, what I strongly assume

Theoretically it should work, but I´m not sure (and haven´t tried it yet). Incognito is based mostly on the Ultimate 1 MB. The U1MB has the REFRESH (REF) signal attached at the Xilinx CPLD and in fact that U1MB emulates the MMU also I assume that U1MB would suspend all activities when REF = low. So Sys-Check as the Turbo Freezer works fine with U1MB. But, Incognito replaces not only the expansion memory, also the standard memory. So there´s no need to recognize the REF signal anymore, because Incognito controls everything. When Sebastian left the logic terms regarding REF in Incognito´s CPLD program code and REF is attached to the IDC header (PBI), then it should work. I asked him this several years (...) ago, but didn´t get any answers to my emails.