fatwizard

Taiwan made. 72 R DA 01337 153 Tag inside. DA 133 REV. A Purchased on eBay.

There is nothing printed on the board under the shifter chip, but I suspect you are right about this. I had actually found the document referenced, and I believe there are pieces missing. Too bad.

Hi all, I bought a pig in a poke on eBay the other day. It's a RAM upgrade board that was removed form a "working" ST. It's called a "Z-RAM-3d/4Meg." by a company called Zubair Interfaces Inc. There was no documentation with this item, but I also bought the motherboard the upgrade was originally installed on. The motherboard had been scrapped out. The socketed chips were removed and the RAM looks like it was removed with a chisel, but the attachment points for the ram upgrade were visible. The problem is there are more connections coming from the upgrade module than there are attachment points on the motherboard. So my hope is that someone here has, or has documentation, or really any information on this ram upgrade.

Yes, spare parts for substituting is an invaluable resource. I had come to the same conclusion about the controller chip, so I pulled a WD2393 out of one of my working 1050s to try in the Rana. No soap. Stll the same. The switches on the back set the default density according to the manual. The drive is still supposed to sense the correct density on it's own. I have been using various DOSs, but mostly I have been trying to get it to work with a copy of SmartDOS 6.1 labeled for Rana systems. I checked the board over again last night, looking for more bad traces, but everything seems in order. I have ordered some replacements for the XR3470ACP amplifier chip as my next best guess. This one has been a challenge. Not as much as my IBM PS2/model 30, but a challenge. It seems that even my EPROM burner is fighting back. It often corrupts the data when I read a 2732. I can erase it, and reprogram the chip, and it will work fine, but if I put it back in my burner and read the contents, it will like as not corrupt the data on the chip. This doesn't happen with other EPROMs I've used. I have no idea what's causing that. Thanks for your replies. I have almost always worked alone, so having someone to bounce ideas with is just supreme.

Thank you 1050. I was having some trouble sorting out the schematic for the drive, but you pointed me in the right direction. Sadly, I measure continuity between the 6522 pin 15 and the 2797 pin 37. When I turn switch four on (to set DD mode), the voltage on that line drops from 5V to 0v. That seems right, but it doesn't work. I should likely be satisfied with the drive as it is, but I have already tracked down a broken trace, and rebuilt the power supply, and otherwise spent a lot of time cleaning and repairing the case, so now I'm being stubborn about figuring it out. I would be the perfect suspect for a newbe foil. I even new better, but during the post I scrolled back to check names, and in my haste I fumbled it. My apologies to Mr. Martian. As for my game ranking, it's likely to stay pretty low. I love working with, and repairing my old computers, but I'm a spaz with a joystick. Don't get me wrong, I play games, I just suck at it.

There is an ad for the Rana 1000 in one of my old Analog magazines that states, "Double Density coming in the future". Earlier in this thread, SD only Rana drives were discussed. Moonsweeper, the topic starter, discussed how the ROM he inspected had a serious MFM bug and wouldn't operate in anything but SD. I am currently using the corrected firmware Moonsweeper posted here for the 6502 variant. Other posters confirmed that it worked correctly, supporting all densities, so I suspect you are right that there is some other issue affecting MFM operation on my drive. My drive has the 6502 CPU with a 4MHz crystal.

Hi all, Sorry to bump this thread, but I'm new here and this thread is on topic for me. I have been collecting third party disk drives for the Atari 8bit line. All the ones I saw advertised in Antic and Analog magazines back in the day that I couldn't afford then. I have discovered that the drives I have gotten, Indus GT, Trak AT-D2, Percom AT99-S1PD, and now this Rana 1000, don't do enhanced or double density without hunting down firmware updates for them. I burnt a copy of the 6502 firmware listed earlier in this thread to a 2732 EPROM and installed it in my Rana 1000, but it still refuses to read ED or DD. Seems to work perfectly in SD. If I boot SmartDOS and reconfigure to double density, the drive will format a disk, but won't verify it. I guess I'm hoping to tap some experience here, I don't know what else to look at for the problem.