tf_hh

Bradley (BEST Electronics) sell them "NOS" (New Old Stock). New, unused SALT extermal test fixture for all SALT versions in an Atari 850 shell for 50 USD. IMHO this is a fair price and there´s no need to clone it until some units are in stock.

As mentioned in my text: KRx lines (KR1, KR2), Pin 16 and 25 from POKEY. Jurgen

As Nezgar already wrote, I strongly recommend to check the RAMs first. In your screenshot you can see a part of the display list (the three little P´s is the start of every standard display lists in the O.S.). This behavior is typical for the often bad Micron (MT) DRAMs when one of the muxed addresslines is defect.

Hi, today I found an absolute new and strange behavior reparing an Atari XEGS. I never have had such an error before neither I found something similar here. So maybe this could help other people with the same strange issue. The XEGS I got comes with the fault description "System hangs if Missile Command is started or sometimes the game just resets" (reset = start from the beginning, same if you would press START at any time). I can reproduce this error easily. So first, I watched the SYNC signal at the CPU - but even when the game hang, there´s activity on SYNC. So I decide first to change the ROM - I have a lot of ROM failures specially by the XEGS. After ROM the MMU was changed. But the fault remains. Ok, next step would be the CPU. CPU failures are from my experience the 2nd most related things after RAM memories. CPU exchanged, but you can imagine... that also didn´t help. BTW: Before I change any part, of course I watched every single pin of the CPU, GTIA, ANTIC and the FREDDIE. All fine. I connect a keyboard, start BASIC, enter some simple calculation endless loops with PRINT´ing them, this works for hours. I attached an SIO2SD, load Missile Command (file version) and... it works. No problems at all. Ok, which components might cause the CPU to make a break... ANTIC? GTIA? All signals (RDY, HALT, IRQ) looks good. After all, I didn´t found other ideas, so I decide to remove all chips, solder sockets in and put well-known working parts into the XEGS mainboard. Start the next test, no keyboard, Missile Command starts and... hang. Now - wished I had test this first, a lot of spent hours would have been saved - I connect the keyboard, start the XEGS with SELECT hold down and Missile Command starts. I didn´t know this before, that Missile Command could be started also with keyboard instead of Atari Basic. I don´t have an XEGS for my own, so I haven´t play around much with this. WITH keyboard attached the Missile Command works fine. No problems. Now I examines the POKEY more then before. Without keyboard I see on the scope, the IRQ line is sometimes low for over 10 times of a PHI2 phase! At every time IRQ goes low for such a long time, the game hangs, resets or makes other weird things. With keyboard attached this never happens, IRQ remains constantly high while the game is running - what I expect, then Missile Command didn´t read the keyboard nor SIO etc., it uses just the joystick ports and console keys, which are attached to the GTIA. After some more examining the POKEY I saw, that pin 16 and pin 25 of the POKEY - KRx lines - are heavy floating from -0.5 volts up to 2 volts. Now it would be clear: POKEY "thinks", a key a pressed, generate an IRQ, but the OS (which is active during the game, ATTRACT will also work) can´t read the source. In case of the bad floating signal the POKEY will generate a long IRQ, longer than normal, which cause the CPU to halt - like some of the "CPU breaker" with R/C links from the 80s. But... the XEGS is MADE for usage without the keyboard... so why this happens? Checking with another XEGS boards, the culprit was found very fast: It was the parsimony of Tramiel´s area, removing some necessary parts to save some cents. The "good working" XEGS has line filters in the KRx (and other) lines, which will prevent these open inputs from floating around and beeing using like an antenna. At this special board, Atari replaces these line noise filters by simple 0R resistors. See this board: The fix is absolute simple, after all I´m so silly not to find this earlier, but... now it works. And maybe it helps others from spending so much time to repair an XEGS Just solder two 1nF capacitors between ground and the both KRx lines - that´s all. Of course you can use wired capacitors, too. Now there´s no floating inputs and the system works fine - with or without keyboard... Jurgen

Hmm, IMHO this is not correct. For example, I can sent up to 500 grams of weight in a box sized 25 cm x 20 xm x 5 cm (length x wide x height) for <7 Euros incl. tracking number and insurance up to approx. 35 Euros (the exact value varies, it´s called "SZR" and a synthetical currency of the international post services). That´s enough for a lof of PCBs and parts, and you can use real boxes, not just aircushioned envelopes. Higher insurance is possible up to 1000 Euros with extra costs. On the other hand, already the smallest envelope with 50 grams will costs 11 US-Dollar from U.S. to Europe. Without any tracking number, without insurance. Today the US-Dollar and Euro are near by 1:1, so it´s more safer and cheaper to sent goods from Europe to U.S. than the other way

Yes, I have some pieces left. Please see order details etc. here: tfhh HW Info Thanks, Jurgen

Thank you very much! Now it´s more clear

Because you state my name (JVR = Jurgen van Radecke, that´s me) in the first part of your text (what´s absolute fine for me!) I want to make sure that everybody knows that I´m also the one who left the jury after one year. The reasons are mainly already spoken out: Personally dislikes against participants of the contest from some members of the jury and missing neutrality. Some other harsh things happened in email correspondence, which I wouldn´t release to the public.

Maybe I´m silly, but until today I have no suggestion how these screws and the single-layer mylar will work. The both pictures in the other thread don´t show really how they are assembled. Could you show any real example, please?

I would buy: minimum 5 pieces 1200XL keyboard minimum 5 pieces 800XL "stackpole" mylar keyboard minimum 5 pieces XE doubly-layer mylar keyboard Jurgen

IMHO more interesting than a new interleave scheme would be the usage of a RAM charger as a track buffer like every Happy or Speedy does...

I´ve tested it - the V1.2 enhanced version doesn´t boot CP/M. When you press the usual keys, nothing happens except a beep.

This is impossible, because all known sector copiers only accept 128 bytes for the three first sectors of each disc. This is the reason why the CP/M boot sectors are destroyed.

Hmm... I didn´t know what this error stand for. Will please Trub to answer.

See my post a few minutes ago at page 5. I would prefer not to use SDX, I´m not sure if that works... untested by me.

Hi, I´m a bit surprised, because I thought the manual in junction with Trub´s website did explain everything. So I will try to summarize all needed steps here again: 1. Take any sector copier you want and copy the following files to one physical real disk using your Indus GT drive each: Indus RAM Charger Check.atr Indus RAM Charger 40-80 Terminal.atr Indus RAM Charger CPM Boot.atr Indus RAM Charger CPM BIOS.atr 2. Boot the disc with no BASIC (OPTION held) from your Indus GT drive containing the file "Indus RAM Charger Check". Press "L" and RETURN, enter "CPMTOOL.COM" and RETURN. 3. Press "1" to test your SRAM charger. First the installed ROM version will be displayed. If your version is below 1.20, then CP/M is not possible! See below. 4. Test your SRAM charger 5. Insert the disc containing "Indus RAM Charger CPM Boot" and press "2" (Fix CP/M boot). Confirm with "Y". A few sectors will be written. 6. Insert the disc containing "Indus RAM Charger CPM BIOS" and press "2" (Fix CP/M boot). Confirm with "Y". A few sectors will be written. 7. Switch off computer, insert the disc "Indus RAM Charger 40-80 Terminal" and power on with OPTION held. 8. DOS XL will be booted and some hints how to continue. Press "F" for the 40 column terminal or "E" for the 80 column version, then RETURN 9. After the terminal software is loaded, only a light green cursor in the upper left corner will be visible. That´s normal. 10. Insert the disc containing "Indus RAM Charger CPM Boot" in your Indus GT drive. 11. Press "DRIVE TYPE" on your drive, hold it down and press the ERROR key. 12. A beep will be hearable, drive boots now CP/M. The message "FUTURE CPM 2.2 REV 1.0 - Hit RETURN to continue" appears, 13. Hit RETURN and a prompt "A>" with a Digital Reseach copyright notice will be displayed. That´s all. Now you can load CP/M programs and use the commands found in the disc(s). A directory is shown by enter "DIR" <RETURN> Important notice on firmware! Some Indus GT drives may have a firmware version below 1.20 - then CP/M can´t be loaded! You´ve to upgrade the Indus GT firmware before. Find the V1.20 firmware here: indus_1.2.rom The firmware can be burned into a standard 2732 EPROM (4 KByte). You didn´t need to change anything on the PCB, just remove the old ROM or EPROM at socket U3 and plug in the new burned 2732 EPROM. There´s an alternative version - V1.2 enhanced: indus_1.2.enhanced.bin This is a patched V1.2 with enables Highspeed-SIO with "standard" Highspeed-SIO routines like Hias´ or the SDX highspeed-SIO-code. Of course it´s not so fast like Happy or Speedy, because there´s no trackbuffer used, but better than without highspeed SIO. This patched version doesn´t support CP/M! Jurgen

Sounds like you didn´t patch the CP/M discs! Look into the manual and links to Trub´s website. Short how-to: - Copy the needed / wanted CP/M discs using any sector copier to real 5.25" floppy discs - Boot the CP/M tool from Trub - Use the repair function to each disc This procedure must be done at last to files "Indus RAM Charger CPM BIOS" and "Indus RAM Charger CPM Boot".

Hi, sorry, again a little later than expected... here are the installation instructions for the SRAM Charger board for the Indus GT and compatible drives: SRAM_Charger.zip Jurgen

I´m working on it. Will be published tomorrow.

Thanks for feedback! Will make the manual ready in the next few days. Heavy workload these weeks at the office, eldest daughter married and much more

Sorry - overlooked. PN sent!

I think not. The circuit at the CPU cards for the 400/800 series will use 12 volt directly from the power supply PCB. There´s a 330k resistor in line, but when you turn the pot at the 12 volt´s end, you can measure - dependent on the manufacturer of the GTIA and if´s NTSC or PAL - something up to 9.5 or 10 volts. Never found a GTIA damaged - only the colors or whole picture disappear. IMHO the old NMOS chips are very robust.

Not so easy. And I wouldn´t recommend that. 1.) you get max. 9.5 volts (from my personal experiences). That´s not enough for some TVs so switch to 4:3 mode 2.) if you take the voltages for SCART etc. from the suggested point, the color setting ALWAYS will change. This have no effect on VBXE RGB or Sophia RGB output, but the normal video circuit and/or UAV is affected.

I use DC/DC converters in SIL package for this reason. Look for "DC/DC converter 0512". They were made from Murata, Traco, etc. - Example items @ ebay UK: QDC1S-0512S or Murata These SIL adapters offers 42 mA or more, but you need only 10 mA for usual SCART televisions, so take the cheapest one. The advantage: No PCB needed and small. I use them for my VBXE installations. It´s not the cheapest way (you get also open PCBs from china for 2 bucks), but safe and easy to install.

I read the article (and the part 1 in the previous Atari Magazin), but there´s no part talking about precompensation. Only the rotation speed of 208 ms (milli-seconds) is named, as you already mentioned.