sup8pdct Posted May 26, 2014 Share Posted May 26, 2014 There is only 1 chip in the ATR8000 that cannot be replaced easily. it is U46 a 74LS288. Alternative? James Quote Link to comment Share on other sites More sharing options...
AtariGeezer Posted May 26, 2014 Share Posted May 26, 2014 There is only 1 chip in the ATR8000 that cannot be replaced easily. it is U46 a 74LS288. Alternative? James There's the 74S288? Quote Link to comment Share on other sites More sharing options...
sup8pdct Posted May 26, 2014 Share Posted May 26, 2014 (edited) It is part of the data separator circuit not far from the FDC. It is marked incorrectly on the PDF schematics. I have corrected it on my updated ones. At least it is what is in mine. James Edited May 26, 2014 by sup8pdct Quote Link to comment Share on other sites More sharing options...
AtariGeezer Posted May 26, 2014 Share Posted May 26, 2014 It is part of the data separator circuit not far from the FDC. It is marked incorrectly on the PDF schematics. I have corrected it on my updated ones. At least it is what is in mine. James Don't ave that one in mine. What I meant was that the 74S288 is a replacement for the 74LS288. What does you think? They have the 74S288 and FDC 1797 on ebay... Quote Link to comment Share on other sites More sharing options...
sup8pdct Posted May 26, 2014 Share Posted May 26, 2014 Don't ave that one in mine. What I meant was that the 74S288 is a replacement for the 74LS288. What does you think? They have the 74S288 and FDC 1797 on ebay... Next question. What bit pattern gets programed into it? What chip is in yours? is it wired same as the 288? James Quote Link to comment Share on other sites More sharing options...
ricortes Posted May 26, 2014 Share Posted May 26, 2014 74S288 here too. Picture of my MB, REV C. Circled in red are just a couple of places of interest. The Atari SIO connector apparently has a couple of through holes, may come in handy. The spot for 34 pin IDE connector. The missing U22. The aux power supply connection. Quote Link to comment Share on other sites More sharing options...
AtariGeezer Posted May 27, 2014 Share Posted May 27, 2014 Here's my Rev-A And a Rev-C I found on the web that shows U46 as a 123 type: Quote Link to comment Share on other sites More sharing options...
AtariGeezer Posted May 27, 2014 Share Posted May 27, 2014 (edited) 74S288 here too. Picture of my MB, REV C. Circled in red are just a couple of places of interest. The Atari SIO connector apparently has a couple of through holes, may come in handy. The spot for 34 pin IDE connector. The missing U22. The aux power supply connection. Can you post a clearer pic of the 74S288 location? Okay I see that the 74S288 on Rev-C is the same type of chip on mine which is a N82S123N. Both are a 256 bit TTL Bipolar PROM 32 x 8... Edited May 27, 2014 by AtariGeezer Quote Link to comment Share on other sites More sharing options...
sup8pdct Posted May 27, 2014 Share Posted May 27, 2014 I had a close look at mine (required an illuminated magnifying glass) at the 74LS288 chip. Turns out it is a 74S288 and 82S123 (both marked on the chip). oops. better fix the schematic. Am now curious as to which FDC every one has in there's. Mine is a 1793B-02. One pic has shows 1797. James Quote Link to comment Share on other sites More sharing options...
a8isa1 Posted May 27, 2014 Share Posted May 27, 2014 I had a close look at mine (required an illuminated magnifying glass) at the 74LS288 chip. Turns out it is a 74S288 and 82S123 (both marked on the chip). oops. better fix the schematic. Am now curious as to which FDC every one has in there's. Mine is a 1793B-02. One pic has shows 1797. James oops. I had my ATR8000 open Yesterday. I have a 1797-something on a Rev C board. I don't remember the qualifier after 1797. -SteveS Quote Link to comment Share on other sites More sharing options...
Caterpiggle Posted June 4, 2014 Share Posted June 4, 2014 You make me want to open mine ATR8000 soon ! Rats .... Quote Link to comment Share on other sites More sharing options...
sup8pdct Posted June 4, 2014 Share Posted June 4, 2014 You make me want to open mine ATR8000 soon ! Rats .... You can send it to me so i can open it on your behalf :D James Quote Link to comment Share on other sites More sharing options...
Caterpiggle Posted June 5, 2014 Share Posted June 5, 2014 (edited) So HERE are many images at once. I believe the daughter-card on the top of empty RAM slot is CO-POWER 88. I see there are yellow wires to switch at the front. Below top board are blurry , too difficult to take those images with my lower quality camera. So please pardon me. See the yellow sticker "64" is 64K ram. At the back of ATR8000, there are reset button with wires inside beside the case. Also the top board is revision "B" instead "A" or "C". Edited June 5, 2014 by Caterpiggle Quote Link to comment Share on other sites More sharing options...
AtariGeezer Posted June 8, 2014 Share Posted June 8, 2014 So HERE are many images at once. I believe the daughter-card on the top of empty RAM slot is CO-POWER 88. I see there are yellow wires to switch at the front. Below top board are blurry , too difficult to take those images with my lower quality camera. So please pardon me. See the yellow sticker "64" is 64K ram. At the back of ATR8000, there are reset button with wires inside beside the case. Also the top board is revision "B" instead "A" or "C". The yellow wires that connect to the front switch which connect to J11 is a Printer ON / OFF toggle... Quote Link to comment Share on other sites More sharing options...
AtariGeezer Posted June 8, 2014 Share Posted June 8, 2014 My status update: Tonight I tested the ATR's memory chips by plugging them into a 800XL and ran the Memory Test, results are good. Also tried booting some CP/M master floppies in the XF551 mech, but still get the same errors returned. I have a couple of FDC 1797's coming Monday, so I'll swap that out and see if that turns out to be the problem or not... Quote Link to comment Share on other sites More sharing options...
Caterpiggle Posted June 9, 2014 Share Posted June 9, 2014 So the chip FDC 1797 is Floppy Controller ? Accord to the web site stated so. Do you have an photo of that chip at least ? Thank you for the tip about yellow wire ! Correct me that the daughterboard is CO-Power 88 ? Is that right ? Any CP/M software will using CO-Power 88 as main driven ? Quote Link to comment Share on other sites More sharing options...
BillC Posted June 9, 2014 Share Posted June 9, 2014 So the chip FDC 1797 is Floppy Controller ? Accord to the web site stated so. Do you have an photo of that chip at least ? Thank you for the tip about yellow wire ! Correct me that the daughterboard is CO-Power 88 ? Is that right ? Any CP/M software will using CO-Power 88 as main driven ? If I understand it correctly CP/M uses only the Z80 processor on the ATR8000 mainboard, while the Co-Power88 daughterboard is for running DOS Quote Link to comment Share on other sites More sharing options...
AtariGeezer Posted June 9, 2014 Share Posted June 9, 2014 So the chip FDC 1797 is Floppy Controller ? Accord to the web site stated so. Do you have an photo of that chip at least ? Yep, it is shown in your 4th picture. Quote Link to comment Share on other sites More sharing options...
Caterpiggle Posted June 9, 2014 Share Posted June 9, 2014 Ahh that photo of mine. Interesting ... So why you need to replace another FDC 1797 ? I am sure your FDC 1797 must be good state, not broken. To BillC, what is the minimum & maximum DOS version to run on CO-POWER 88 ? Quote Link to comment Share on other sites More sharing options...
AtariGeezer Posted June 9, 2014 Share Posted June 9, 2014 Ahh that photo of mine. Interesting ... So why you need to replace another FDC 1797 ? I am sure your FDC 1797 must be good state, not broken. Well, it's not reading the floppy drives anymore, just eliminating a possible cause... Quote Link to comment Share on other sites More sharing options...
BillC Posted June 10, 2014 Share Posted June 10, 2014 Ahh that photo of mine. Interesting ... So why you need to replace another FDC 1797 ? I am sure your FDC 1797 must be good state, not broken. To BillC, what is the minimum & maximum DOS version to run on CO-POWER 88 ? http://atariage.com/forums/topic/76546-co-power-88-atr8000-on-ebay/?do=findComment&comment=934572 Quote Link to comment Share on other sites More sharing options...
AtariGeezer Posted June 12, 2014 Share Posted June 12, 2014 Status update: installed a new FDC and now it will boot the ds/dd mydos disks. write to mydos disks, boot/read CP/M disks, but won't format a disk in either mode on a 3.5 or 5.25 drive... Quote Link to comment Share on other sites More sharing options...
tregare Posted June 12, 2014 Share Posted June 12, 2014 If I understand it correctly CP/M uses only the Z80 processor on the ATR8000 mainboard, while the Co-Power88 daughterboard is for running DOS or CP/M 86 Quote Link to comment Share on other sites More sharing options...
Tempest Posted June 12, 2014 Share Posted June 12, 2014 Quick question. Is there an easy way to tell if a co-power add-on is 128K or 256K? I have no idea which version mine is and I really have no way to test it. Quote Link to comment Share on other sites More sharing options...
AtariGeezer Posted June 14, 2014 Share Posted June 14, 2014 Status update: installed a new FDC and now it will boot the ds/dd mydos disks. write to mydos disks, boot/read CP/M disks, but won't format a disk in either mode on a 3.5 or 5.25 drive... I tried all 3 of the New FDC's that I bought and all 3 work the same, so I must have a weak TTL chip in-line with the FDC... Quote Link to comment Share on other sites More sharing options...
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