BillC Posted June 5, 2012 Share Posted June 5, 2012 Yes, but it's AC. So peak voltage is square root of 2 multiplied with the mean voltage ov 9 V. Isn't it? I said in my original post that I wasn't bothering to multiply by 1.4, if you take that into consideration C104s peak voltage is actually about 24VDC. I was just trying to show that the voltage doubler circuit is capable of supplying more than sufficient voltage for a steady output from the 7812(multiplying by 1.4 wasn't necessary), as long as C104 holds enough energy to keep above the 7812's minimum input voltage(about 14V) between charging pulses from C102. The size of C102/C104 is specified to keep the voltage above this level at the designed current draw, the higher peak voltage resulting from multiplying by 1.4 means that the size of C102/C104 can be smaller since C104 can now discharge about 10V without dropping below +14V. Quote Link to comment Share on other sites More sharing options...
31336haxx0r Posted June 6, 2012 Share Posted June 6, 2012 Okay, then we were talking about the same thing. Quote Link to comment Share on other sites More sharing options...
w1k Posted June 9, 2012 Share Posted June 9, 2012 hmm, power suply for my xf551 died today Quote Link to comment Share on other sites More sharing options...
31336haxx0r Posted June 9, 2012 Share Posted June 9, 2012 There are step-by-step instructions out there in the web describing how to mod it for external switch mode PSUs. I used to be familiar with the Intel MCS-48 family. But I forgot almost everything by now. Now what I always wanted to know, can I use a 8042 that was used as a keyboard controller in old PCs in the XF551? Quote Link to comment Share on other sites More sharing options...
Dropcheck Posted June 9, 2012 Share Posted June 9, 2012 Update: I have just about finished putting together a schematic that utilizes Guss Assmann's design with the added benefit of being able to do a drop in replacement for the XF551 original motherboard. It will use an external power supply to supply the +12V and +5V DC needed. I am in the process of nailing down parts that will work and fit the original XF551 case without modification. Hopefully in another week or so I can show a 3d mockup of what the board will look like if made. I want to thank everyone that has contributed, especially Mr Assmann. I am standing on his shoulders. All errors are due to my poor understanding. Standby, Quote Link to comment Share on other sites More sharing options...
venom4728a Posted June 9, 2012 Share Posted June 9, 2012 Update: I have just about finished putting together a schematic that utilizes Guss Assmann's design with the added benefit of being able to do a drop in replacement for the XF551 original motherboard. It will use an external power supply to supply the +12V and +5V DC needed. I am in the process of nailing down parts that will work and fit the original XF551 case without modification. Hopefully in another week or so I can show a 3d mockup of what the board will look like if made. I want to thank everyone that has contributed, especially Mr Assmann. I am standing on his shoulders. All errors are due to my poor understanding. Standby, Fingers Crossed, That this gets made Quote Link to comment Share on other sites More sharing options...
w1k Posted June 11, 2012 Share Posted June 11, 2012 my power supply is dead. can i use this?: http://www.dealextreme.com/p/replacement-9v-2a-us-plug-power-supply-adapter-for-router-more-5-5-x-2-1mm-1m-124162?item=4 http://www.dealextreme.com/p/9v-2-2a-power-supply-adapter-5-5-x-2-1mm-connector-125358?item=2 Quote Link to comment Share on other sites More sharing options...
AtariGeezer Posted June 11, 2012 Share Posted June 11, 2012 Those are 9V DC adapters, you need a 9V AC adapter... Jay Quote Link to comment Share on other sites More sharing options...
BillC Posted June 11, 2012 Share Posted June 11, 2012 (edited) my power supply is dead. can i use this?: http://www.dealextre...m-124162?item=4 http://www.dealextre...r-125358?item=2 Those both appear to be DC power supplies, the 810/1050/XF551 all require 9VAC, the stock power supply is about 3A. Actually 3.4A, 3A should be sufficient but I don't believe 2A would be. The Atari AC power supplies contain a fuse, if you break/cut open the seam around the bottom you can get to and replace the fuse. Edited June 11, 2012 by BillC Quote Link to comment Share on other sites More sharing options...
w1k Posted June 11, 2012 Share Posted June 11, 2012 i cant.. its trashed :/ i opened it before.. Quote Link to comment Share on other sites More sharing options...
BillC Posted June 11, 2012 Share Posted June 11, 2012 Those are 9V DC adapters, you need a 9V AC adapter... Jay You beat me by a few seconds, I see you're up late too. Quote Link to comment Share on other sites More sharing options...
AtariGeezer Posted June 11, 2012 Share Posted June 11, 2012 (edited) Those are 9V DC adapters, you need a 9V AC adapter... Jay You beat me by a few seconds, I see you're up late too. LOL, Yep... I'm a night owl. My internal clock is off by 8 hrs Edited June 11, 2012 by AtariGeezer Quote Link to comment Share on other sites More sharing options...
Dropcheck Posted June 14, 2012 Share Posted June 14, 2012 A question: Should I fuse the power inputs or trust the power supply to break first. It claims short circuit protection..... eBay Auction -- Item Number: 190391450076 Quote Link to comment Share on other sites More sharing options...
+bob1200xl Posted June 14, 2012 Share Posted June 14, 2012 A regular Atari 9vac supply is just a dumb transformer that is fed from the 15 amp wall socket. If the load shorts, you would have to trip a 15 amp breaker to kill power into the device - on the other side of the 9 volt output... lotta smoke, I would think. That's why the Atari supply has a fuse. That switching supply either shuts down if the load faults and/or is fused already. I wouldn't think that you need to add anything to it. Bob Quote Link to comment Share on other sites More sharing options...
Dropcheck Posted June 22, 2012 Share Posted June 22, 2012 Well I think this might need to move to an official thread.... I've mocked up a 3d rendering of what the board should look like. Some of the parts eagle 3d and povray just don't understand but at least the outline is there. It's about 80-90% done. There is one feature that I would like to add but until I can confirm approval I am not going to talk about it yet. In general: Board Size: 150mm x 100mm (about 2 inches less length than original) Should be a dropin replacement for current motherboard Uses an external power supply with apropriate connector (Not Atari power supply) Will have builtin 4in1 OS switching (currently original XF551, Bob Wooley's Mod and Hyper-XF with a fourth if approved) Will have an extra internal SIO connection for future options Uses standard 3 1/2 and 5 1/4 floppy IDC data and power connectors Price = ? depending on number ordered and paid for I'll know more when I've debugged a prototype. Hopefully I can finalize the board layout in the next week and then send it out to have the proto made. 1 Quote Link to comment Share on other sites More sharing options...
BillC Posted June 22, 2012 Share Posted June 22, 2012 Well I think this might need to move to an official thread.... I've mocked up a 3d rendering of what the board should look like. Some of the parts eagle 3d and povray just don't understand but at least the outline is there. It's about 80-90% done. There is one feature that I would like to add but until I can confirm approval I am not going to talk about it yet. In general: Board Size: 150mm x 100mm (about 2 inches less length than original) Should be a dropin replacement for current motherboard Uses an external power supply with apropriate connector (Not Atari power supply) Will have builtin 4in1 OS switching (currently original XF551, Bob Wooley's Mod and Hyper-XF with a fourth if approved) Will have an extra internal SIO connection for future options Uses standard 3 1/2 and 5 1/4 floppy IDC data and power connectors Price = ? depending on number ordered and paid for I'll know more when I've debugged a prototype. Hopefully I can finalize the board layout in the next week and then send it out to have the proto made. Why not make provision for using a 27256, allowing up to 8 OS selections(4*5.25" + 4*3.5")? This would only require pin 27(A14) of the ROM socket to be selectable instead of tied to +5V as needed for the 27128. This may not be a feature used by many but it wouldn't add much to the cost, and it would allow 1 EPROM to contain enough firmware selections to satisfy almost anyone. Quote Link to comment Share on other sites More sharing options...
sup8pdct Posted June 22, 2012 Share Posted June 22, 2012 A regular Atari 9vac supply is just a dumb transformer that is fed from the 15 amp wall socket. If the load shorts, you would have to trip a 15 amp breaker to kill power into the device - on the other side of the 9 volt output... lotta smoke, I would think. That's why the Atari supply has a fuse. That switching supply either shuts down if the load faults and/or is fused already. I wouldn't think that you need to add anything to it. Bob I don't know about other countries, but her in oz, the transformers are protected by a thermal fuse under the tape of the primary. I did one once when i shorted the end that plugs into the drive (don't ask) James Quote Link to comment Share on other sites More sharing options...
Fox-1 / mnx Posted June 22, 2012 Share Posted June 22, 2012 One thing I don't get is, why not make the board the same size as a 3,5" mechanic? Would be nice to give all those old ST351/ST354 a second life while the borad itself still fits a stock XF551 case. OTOH, it's his project and it's probably not his goal :-) Quote Link to comment Share on other sites More sharing options...
BillC Posted June 22, 2012 Share Posted June 22, 2012 One thing I don't get is, why not make the board the same size as a 3,5" mechanic? Would be nice to give all those old ST351/ST354 a second life while the borad itself still fits a stock XF551 case. OTOH, it's his project and it's probably not his goal :-) The layout is designed so that it's a drop-in replacement of the original XF551 circuit board, the jacks line up with the holes in the XF551 case. Quote Link to comment Share on other sites More sharing options...
Fox-1 / mnx Posted June 22, 2012 Share Posted June 22, 2012 The layout is designed so that it's a drop-in replacement of the original XF551 circuit board, the jacks line up with the holes in the XF551 case. I know, but that doesn't mean it can't be made the size of a 3,5" mechanic. Jacks won't match anyway when used in a non-XF551 case so it can be used sideways. Quote Link to comment Share on other sites More sharing options...
31336haxx0r Posted June 23, 2012 Share Posted June 23, 2012 I wonder, is it possible to hack the XF in such a way it can handle 2 disk drives? The WD1772 can access 2 disk drives as obviously seen in the ST. As only one SIO device can be active at a time, there would be no trouble with both drives getting accessed at the same time by the computer. One must "just" modify the firmware in such a way that the drive number selected by the dip switch is drive 0 on the FDC and dip switch + 1 is drive 1 on the FDC. It would be great to have a 5 1/4" and 3 1/2" drive simultaneously. The 3 1/2" drive could be mounted externally, like ST's ST314 disk drives. Quote Link to comment Share on other sites More sharing options...
BillC Posted June 23, 2012 Share Posted June 23, 2012 I wonder, is it possible to hack the XF in such a way it can handle 2 disk drives? The WD1772 can access 2 disk drives as obviously seen in the ST. As only one SIO device can be active at a time, there would be no trouble with both drives getting accessed at the same time by the computer. One must "just" modify the firmware in such a way that the drive number selected by the dip switch is drive 0 on the FDC and dip switch + 1 is drive 1 on the FDC. It would be great to have a 5 1/4" and 3 1/2" drive simultaneously. The 3 1/2" drive could be mounted externally, like ST's ST314 disk drives. It's already been done by CSS, but it hasn't been available for years. The XF Dual Drive Upgrade Quote Link to comment Share on other sites More sharing options...
31336haxx0r Posted June 24, 2012 Share Posted June 24, 2012 Oh crap. Seems like I should get my MCS-48 assembler skills up to par. Quote Link to comment Share on other sites More sharing options...
w1k Posted November 2, 2012 Share Posted November 2, 2012 hmm, can i use this? Quote Link to comment Share on other sites More sharing options...
flashjazzcat Posted November 2, 2012 Share Posted November 2, 2012 That's another DC adapter. As Jay said: you need 9V AC. Quote Link to comment Share on other sites More sharing options...
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