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Member Since 11 Apr 2010
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#3965748 Atari 800 S-Video Problem

Posted by BillC on Sun Feb 18, 2018 1:36 AM

Could the color differences be due to CTIA vs. GTIA? Do you know which chip your 800 has?


I don't remember any color difference between the CTIA & GTIA, but is has been over 30 years since I have had a CTIA. The GTIA does have more video modes.


The color on the Atari computers can be adjusted via a potentiometer.


On the 800 this potentiometer is on the CPU card, and can be adjusted through a hole on the back of the RF shield when the cover for the RAM/OS card bay is removed.

#3962270 Anyone sell an Atari 400 capacitor kit?

Posted by BillC on Wed Feb 14, 2018 4:52 AM

For posterity and to help with the project, as it may be needed someday... maybe someone would be inclined to post the 400's build out sheet or maybe he could simply look through a bunch of photo facts etc.

The parts list for the 400 is already in the back of the 400-800 Home Computer Field Service Manual, available at Atarimania.

#3962135 OSNXL & OMNIVIEW 80 XL

Posted by BillC on Tue Feb 13, 2018 10:25 PM

The speedscript 80 looks pretty good. I think the type is easier to read than the Last Word but that is probably due to the screen colors. If Last Word used white on black it would probably be much easier to read.

According to the v3.21 manual the screen color in Last Word is adjustable, the default value is 148 but can be set from 0 to 255.

#3952835 Another unknown EPROM...

Posted by BillC on Sun Feb 4, 2018 2:26 AM


Looks like somebody knew what they were doing when they did the mods for my 810 sideboard.  Thanks for the manual.  By the way...

Did they make an Archiver chip for the 1050 too?



B&C/myatari.com sells a Super Archiver upgrade for the 1050.

#3948880 Powering XL's & XE's off of USB phone chargers, etc

Posted by BillC on Tue Jan 30, 2018 12:48 PM

The issue with using USB chargers is that some won't deliver over 500mA current without USB protocol handshaking. This is why some older external 2.5" HDD enclosures use a Y cable which allows them to draw power from 2 USB ports.


I have tried several USB chargers, that work with iPhones, which are unable to charge my Android phone because they use different protocols to enable higher current.

#3936373 Atari 810 with some sort of Mod

Posted by BillC on Mon Jan 15, 2018 10:35 PM

Great pics! So the second pot in there is definitely to set a slower RPM for copying protected disks that containted tracks with more than 19 sectors, or to create bad sectors manually. Is there any external switch to toggle?


I've personally never owned a Happy mod in an 810 (yet! just 1050's) but this definitely appears to be an early revision of the Happy 810. It won't support Ultraspeed like the later Happy Rev 7 board (3x SIO, US Doubler Compatible), but will do 'Warp Speed' which is 2x SIO, proprietary to Happy and not compatible with most software like SpartaDOS that uses Ultraspeed protocol. Can't remember if Hias's latest highspeed OS patch supports happy 'warp' speed protocol.


Try out these disks:

Happy Warp Speed Software v5.3 (19xx)(Happy Computers)(US) https://archive.org/...py_Computers_US
Happy Warp Speed Software v6.6 (19xx)(Happy Computers)(US) https://archive.org/...py_Computers_US
Warp Speed DOS 7 (1985)(Happy Computers) https://archive.org/...Happy_Computers

The RAM/ROM test diagnostics on the first two disks may give a hint at further confirmation of the version. They also have a high speed sector copier. Of course the 'Happy Backup' function is the other hallmark, which allows it to copy many copy protected disks. Less of course than the later revisions.


The Warp Speed DOS is a modified Atari DOS 2.0S that loads a patched SIO routine.

Not that early a Happy 810 upgrade, the initial one's were done using point to point wiring instead of a PCB(the side board had to be shipped to Happy).

The following link shows such an upgrade.


#3923389 Problem loading disk images in AspeQt with SIO2PC/10502PC Dual USB v 3.3

Posted by BillC on Sat Dec 30, 2017 3:13 PM

The power supply went on my disk drive,I did have it plugged into it at the time,I have a data recorder as well that uses the same PSU,I only have one,Both Item don't work so got to fix the PSU now. All my pins are ok and straight.

The 9VAC power supplies Atari used  have an internal fuse. The case on most are glued together, but the seam at the bottom can be carefully broken open in order to replace the blown fuse.

#3921148 1088XEL Atari ITX Motherboard DIY Builders Thread

Posted by BillC on Wed Dec 27, 2017 2:00 PM

On those stacked video connectors, observe that two of the anchor points that will be soldered have a plastic post on one half (don't know why they made them this way  :? ). So be sure to only apply heat to the metal side when soldering, otherwise you'll have a stinky mess.

Maybe those 2 outside anchors aren't meant to be soldered, the plastic piece has a tooth to catch on the underside of the PCB.

#3910058 What's the latest Atari related thing(s) you've bought on ebay?

Posted by BillC on Tue Dec 12, 2017 4:08 AM

Good catch. Looks like I got confused with the next one the seller posted on ebay that I'm watching, not sure where the card edge connector is on it, maybe right up against the case on the back: https://www.ebay.com/itm/222716933109 Maybe coming from same seller, this has a higher likelihood to be DD?

This was the one I got, AT88-S1: https://www.ebay.com/itm/222716613498

That is the almost the same drive as mine, but the add-on card is larger with more chips. This is likely the double density card rather than just a data separator like mine.


The end of the PCB sticking out the back left is for connecting slave drives, there are jumpers to configure and the terminator chip would have to be removed. This Percom drive doesn't have a printer port.


A manual is available on Atarimania. http://www.atarimani...rive_manual.pdf





On the AT88-A1 slave mechanism the card edge for the ribbon cable appears to be sticking out between the side and back panels, to the left of the fuse holder.

#3904683 Best 8-bit Atari disk drive? 810, 1050, XF551

Posted by BillC on Mon Dec 4, 2017 11:48 PM

Even the ST/TT computers were only 720k until they used hand selected / tested WD1772 chips in order to be HD capable, when Atari couldn't obtain these any more they developed the AJAX FDC. 



#3904167 The UAV Rev. D Video Upgrade Thread

Posted by BillC on Mon Dec 4, 2017 12:38 PM


Even with the RF modulator removed. you can still get artifacting from the Composite signal, which the UAV still produces. Separating the chroma and luma signals for S-video gives you an image that is basically too sharp for artifacting. It's your choice which signal(s) you want to connect to your display.


Having said that, I believe (not 100% certain) that some PAL models have video circuits contained within their RF modulators that produce the Composite signals in stock configuration. If you remove the RF modulator on such machines, you MUST use a video mod to produce video signals. 

I don't know whether it's NTSC or PAL models, or both, but the modulator in the 130XE has circuitry which combines Y/C signals to produce the CVBS signal.

#3900522 Protecting SIO ports, what is there

Posted by BillC on Wed Nov 29, 2017 1:12 PM

While the Quintopus is no longer available, I believe the EasyIO Spider is. 



#3895273 93'rd 800 made?

Posted by BillC on Tue Nov 21, 2017 5:11 PM

The incompatibilities of the 1200XL OS with existing software, and discounted prices on the 800, caused demand for the 800 which lead to production being continued for a period in 1983.


I have a late production 800(233 date code) with a low serial number(83A AW 00620) due to it being manufactured by Atari-Wong in Hong Kong.


#3894279 1200XL - Clearpic or SuperVideo 2.1?

Posted by BillC on Mon Nov 20, 2017 11:16 AM

Sorry, rarely read those ;) Thanks for the pointer, this is good news. I read up on the mod details and while it's really quite extensive it seems doable for me.


As the article states that you can't observe the difference the CV disable switch makes on a colour monitor, can it be omitted. I doubt I'll ever find a monochrome monitor and if I find one, I'd rather hook it up to an XEP80 or Bit3 (should I ever get hold of the latter).


The article also instructs to twist together two 150 Ohm resistors to get 75 Ohms. Is that because there is no 75 Ohm resistor in the kit that's mentioned or does using two in parallel make any beneficial difference electronically?


Finally, I have some early revision UAV video mod boards at hand. I gather that SV 2.1 is preferable to UAV?

75 ohms is not a standard resistor value, the closest are 68 and 82 ohm. BITD some specialty electronics stores did carry them, but they weren't common.


I bought a bag of 100 carbon film 75 ohm resistors for $2 in the late 80's at RP Electronics. At the time it was just a small local shop, it has since moved to a larger location and also added a website. They still sell bulk packs of 75 ohm resistors for under $2.



These days 75 ohm resistors are readily available via the internet.

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#3894084 What is this Atari 400 mod?

Posted by BillC on Mon Nov 20, 2017 2:14 AM

Wonderful stuff......all of it damn impossible to find here....and you should get a fine for transporting it carelessly like that esp. the 810 and I guess that's a HD under it.... :D :D hope the HD heads survived the bumps of the ride....

That's likely the dual 5-1/4" FDD for the ATR8000 instead of a HDD.