BillC

Since the 400/800 didn't ship until the end of 1979 I would think the copyright date is for another computer system(Apple II/Commodore PET?), with an Atari version in 1979 or 1980. EDIT: The cassette label has a 1980 copyright date.

An issue I have encountered with Windows 10 is the inability to delete large multi-layer tiff files exported from GIMP.

Older versions of the 810 came with a power board that was prone to failure, Atari made a newer version that also split off some circuitry into a separate analog R/W board that installs on top of the 810 mechanism. If your 810 doesn't have a PCB installed on the top of the mechanism you have the older version which has probably failed, and that blew the fuse in the power supply. If this is the case you should replace the original single power supply board with the newer power supply/analog boards combination. Information about the replacement below is copied from Best Electronics website. Atari Engineering Grass Valley 810 Analog Rear board upgrade set. New Rear 810 Analog Rear Power board, New Top Analog R/W board, New 10 Pin Jumper cable, Installation Instructions. Upgrades / Replaces the older Atari 810's with Single Power board that 100% Fails. CB101128 $79.95

The SYSCHECK II can be used as 64KB base RAM but the are some restrictions: Use as base RAM replacement disables the cartridge port. With the V2.2 base RAM replacement and as extended memory can't be used together.

AFAIK all 600XLs were completely socketed.

Those resistors from +5V to the SIO signals are pull-up resistors, don't remove any of them. These signals are pulled low by the source ICs. You do probably want to remove the capacitors on the DATA-IN, DATA-OUT and COMMAND signals to improve higher speed SIO operations, according to the schematic these would be C184/C185/C188.

The FAQ lists the programmer as Curtis Laser. I don't know if it's him but 411.com has 1 match for that name who lived in California, Custis A Laser in his 60's currently living in Eagle ID.

Just thought you should be aware that the UAV would change the artifacting mode of the video output to XL type. This also affects the output of the UAV on the Super Color CPU Card from tf_hh.

I bought the second bottle because this was the lowest price I can remember(have been buying it for over 25 years, had issues finding the 99% variety back then) plus the fact I have dozens of original floppies to dump, some of them with rarity 9 or 10 on Atarimania and no dumps/disk images at a8preservation.com. After my experience of destroying the oxide layers on 2 of 4 SpartaDOS floppies dumped I am going to be somewhat compulsive about head cleaning, and have also ordered a modified drive to increase the chances of dumping both sides of flippy disks.

Here's another 1200XL, no power supply and untested, at almost $300 with over 2 days to go. https://www.ebay.com/itm/114827899785?_trkparms=aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D20200818142401%26meid%3Db5817e3f4a214569a84eb1bce44660a0%26pid%3D101124%26rk%3D4%26rkt%3D12%26sd%3D154467378883%26itm%3D114827899785%26pmt%3D0%26noa%3D1%26pg%3D2563228%26algv%3DDefaultOrganic%26brand%3DAtari&_trksid=p2563228.c101124.m2109

The prices I found on Amazon.ca were much higher than the $10/l I paid locally for 2-500ml bottles, most were at least double. The store I purchased it is where I usually shop for groceries anyways, Real Canadian Superstore, so no special trip was needed. I haven't been using floppies much in recent years, mainly ATR images on Sdrive NUXX or CF card via IDE+ 2.0/SIDE cartridge, so the now almost empty 500mL bottle I have is at least 5 years old. Not that I am going to be dumping flux images I purchased more IPA in order to keep cleaning the heads frequently, I had used a cleaning disk, waiting several minutes after cleaning to give the alcohol time to evaporate, before dumping the SpartaDOS 1.1 disks that got damaged. I was able to get 2 successful dumps of the V1.1+ disk(had 3 originals of that SpartaDOS release), the dump of the V1.1 disk had 10 missing and 1 damaged sectors that affected 2 files, Farb from a8preservation.com was able to use data from the v1.1+ dump to recover STANDARD.DOS(the DOS files are the same on both releases), but has been unable to recover AT_RS232.COM yet. Afterwards I used some IPA/cotton swabs to clean the drive, I was surprised how little there was on the heads/mechanism, I think most of the oxide coating that peeled off must have stayed inside the disk jacket. I have ordered some MG Chemicals 407C Audio/Video Head Cleaner as well(probably not necessary) to use for a final cleaning after the IPA, and also a small dental inspection type mirror to do a visual check of the upper head.

I don't know about where you live but I just purchased 99% isopropyl alcohol locally yesterday for a much lower price than currently available on eBay, 2 - 500mL bottles at C$5/bottle. It's carried by many Canadian pharmacies, I have been purchasing it from different pharmacies wherever I have lived for about 30 years.

When dumping older disks it is recommended to clean the heads frequently, the oxide layer on vintage disks can come off and contaminate the heads damaging any other disks accessed later. I recently had 2 original SpartaDOS V1.1 disks(probably 30 to 35 years old) that had the oxide layer come off both sides, I could see through the mylar, while dumping them with a Greaseweazle and a Mitsumi D503 from an XF551. I have put a hold on any more dumping until a no-flip modified drive I purchased arrives, since this would increase the chances of dumping both sides of a flippy disk. 5.25" cleaning disks have a limited lifespan, most are only supposed to be used 15 to 30 times, and replacements are getting expensive/hard to find. Another method of 5.25" head cleaning is with magnetic head cleaning solution/isopropyl alcohol combined with cotton/foam tip cleaning swabs, this requires access to the top of the mechanism. I have also purchased a dental inspection type of mirror to allow visually checking the upper head. I have some old external SCSI chassis that are deeper with the power supply completely behind the drive bays, the upper bay is completely exposed with the cover removed. This is the type of external chassis I would recommend for dumping if a 5.25" mechanism is involved. It would also be handy to make a small bracket that allows mounting whichever flux device you use, with the USB port accessible, in place of the SCSI connector.

Still much better than the text catalogues Bravo Sierra currently uses, and that myatari.com/B&C used until the Windows XP machines used to keep track of prices/stock levels crashed several years ago.

There are solutions to the need for additional serial ports, I have an old 4 port card with 16650 UARTs capable of 460kbps/port but unfortunately it's an ISA card.