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Member Since 11 Apr 2010
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#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.

#3891485 XEL-CF Compact Flash Adapter for 1088XEL (formerly XEL-I3)

Posted by BillC on Thu Nov 16, 2017 12:11 AM

WARNING Do Not Purchase SanDisk CF Cards From China


I just discovered that the ten 1GB SanDisk cards that I got for a great deal on eBay, turned out to be fakes (not such a great deal after all :( ). They still work in a PC as far as I can tell, but they won't work in the XEL-CF or likely a SIDE2 either. First indication that there was a problem happened when I performed an FDISK and the card ID came up blank, when it should have said: SanDisk SDCFJ-1024. Then the next problem was that I could not initialize the card. And finally I noticed that the labels were all bubbled, which I've never seen on any of my other SanDisk cards. All of these discoveries applied to all ten cards I had purchased.


Then to add insult to injury, when I initiated a return with eBay the customer refused to pay for the return postage. And yes as the header to this post says, these came from China. Not to say that all things from China are bad, but it's also not a big surprise either that someone over there would pass off some generic brand CF card as a NEW SanDisk card figuring that all of that ocean between us would protect them from an unhappy customer like myself. And since these seem to work fine in my PC, most people wouldn't know the difference anyway.


So moral of the story is only buy SanDisk cards from a trusted source.


And to reiterate, ONLY USE Genuine SanDisk Cards in the XEL-CF, no other brand will likely work (including fake ones with SanDisk labels pasted on ;) ).


- Michael 

If the item wasn't as described then the seller is supposed to pay return shipping. IMO counterfeit SanDisk CF cards should qualify.


Following is from eBay:

When the item isn't as described:

If you return an item because it's not as described in the listing, arrives damaged, or is missing parts, then your refund is:


In these situations, the seller can't charge a restocking fee and the seller pays the return shipping charges.

#3891132 The UAV Rev. D Video Upgrade Thread

Posted by BillC on Wed Nov 15, 2017 2:51 PM

Heading to the Post Office!

FYI, a hairdryer or heatshrink gun softens the adhesive on old labels and makes them easy to remove.

#3885374 New development: GTIA in CPLD

Posted by BillC on Tue Nov 7, 2017 2:05 AM

Has anyone fitted one to a 400?

It would be very difficult since there's not enough room under the RF shield for it to plug into the socket on the CPU board.


It has been done on the 800, using a ribbon cable to the RAM card bay in an Incognito upgraded machine.


It might be possible to do similar on the 400, though it could require locating the Sophia outside the RF shield.

#3885143 1200XL - Clearpic or SuperVideo 2.1?

Posted by BillC on Mon Nov 6, 2017 4:57 PM

Is there a set of updated instructions for the supervideo 2.1 upgrade for the 1200XL? I know there is one for the 800XL which instructs the user to replace resistors rather that piggybacking in order to achieve the desired resistance.

Piggybacking resistors would have the same affect as a singe one of equivalent value, the single just looks neater.


Brian's UAV mod is a more recent solution: http://atariage.com/...e-thread/page-1

#3882466 130XE Electrical Problem

Posted by BillC on Thu Nov 2, 2017 8:03 PM

Sam's manual says to check C2 for 5v, I know where C2 is and I can check it but I can't find any reference to what the nomenclature is for the capacitor in case I need to replace it.  Does the 130XE generally have the same part designators as the 800XL; I have a parts list for the 800XL.

C2 is a 22uF 16V axial electrolytic capacitor, the 130XE Reference Manual from Atari has a parts list at the front of the book.

#3877924 Upgrade Atari 800XL Basic to revision C

Posted by BillC on Fri Oct 27, 2017 4:31 PM

While you're at it, burn extra Rev. C eproms and replace the ROM in the old Atari Basic carts too :D


Learning how to use the eprom burner I got from DropCheck has been on my to-do list for a long time.. I have lots of 600XL's and 800XL's that would be an easy chip swap upgrade.

It wouldn't just be a chip swap in the Rev.A BASIC cartridge, its PCB used 2-4k 24-pin ROM chips.


I have done it using a 16k EPROM cartridge PCB, disabling a trace to the edge connector as per the post linked below to make it only 8k.


#3877867 Upgrade Atari 800XL Basic to revision C

Posted by BillC on Fri Oct 27, 2017 3:18 PM


Depends what you want Basic for, do you plan on programming?   IIRC, the worst bug in Rev B was that it would sometimes freeze while you were typing in programs.   If you aren't typing in programs, then B wasn't all that bad.   But if you are planning on doing Basic programming, you may want to check out one of the improved 3rd party basics

IIRC it was Rev.A(cartridge) that would lock-up. Rev.B added some extra bytes to the program every time it was saved, the extra bytes could be removed by using LIST to write the file to disk, then using ENTER to reload it.

#3875892 Who's using modern printers?

Posted by BillC on Wed Oct 25, 2017 12:18 AM


Wow, I haven't used a dot matrix in a long time, but you're right I see lots of options, including a box of 2500 sheets of 8.5x11 on the US staples:

https://www.staples....d printer paper


But I don't see anything (at least online) for staples.ca. Have you seen options available in-store?  I know I've seen places like airport checkin and courier shipping desks still using those good 'ol Okidata Microlines's still. They're getting it somewhere...


Edit: Search and you will find... :D found 8 1/2" at Grand & Toy: https://www.grandand...uous_Paper.aspx

Canadian office supplies, smaller box of 1000 8.5.x11 https://canadianoffi...aper/SPR02184/p

2500 sheets $51 http://www.buyonline...er-SPR00408.asp


Staples.ca does have it as well, according to the website most stores in my area have 2 boxes of "Blank White Computer Paper, Ultra Perforated, 20 lb., 9-1/2" x 11", 2,200/Box", and a Regina store is supposed to have 1 box.


#3875584 Who's using modern printers?

Posted by BillC on Tue Oct 24, 2017 3:44 PM

I've recently pulled a XMM801 out of Deep Storage and was thinking about starting it up for light use, but tractor-feed paper is becoming hard to find and, well, there are certainly better options for light home use. Is anyone using modern inkjet or laser printers with their A8 units? Show me your set-ups!

While more expensive than normal 8.5"x11" paper, 9.5"x11" tractor feed paper is still available from Stapes in both Canada and the US.