Senior Tech

Okay, then the J4 connector soldering particularly pin 10 and 16. Or something with the cable crimping to the connectors.

On the Disk Drive Mech. it's self: Make sure it is still patched for D0. Look down through and "L" shaped opening in the shield, a double row of 4 pins marked 0-3. The two pins for D0 should have a jumper on it. Every thing being said sounds like th drive is not patched or patched as some other drive.

So I guess you're the one. I have two myself and just repaired 4 others for another person. Broken traces on the SIO connectors and on Pwr connectors mostly A good head cleaning, putting in the HYPROM B prom and they work great. Yeah, I'm working on 3 of those CSS dual drives. One has a reversing switch on the DS1 and DS2. Suppose to swap the floppy drives. Had to rewire the SIO interfaces and the pwr connectors. I do have one of them working, switch on the front for CSS mode and 1050 mode. 1050 mode is to format and write to flippies, no need for the index hole. Thanks for answering my question; Senior Tech

Yes it is. But HYPROMA or HYPROMB is what the file name is and is on the chip label. So, I try to keep it simple.

Yes, I just read them. But no where does it say to cut the foil off the J4 (Ribbon cable) connector, pin 10 (S0) and wire the foil to pin 12(S1). I'm trying to find out who built these drives in the first place. I have 2 (working) and I just worked on and repaired 4 others. They all had some other code in them, I won't say whose, and I changed them all to the Hyper XF ROM, HYPROM B on the label.

I just checked the 551 schematic. pin 10, DS0; pin 12, DS1. MO is pin16. Pin 14 is DS2, not connected.

Then are you the one that came up with this mod? I haven't seen anything, anywhere about making this mod to the cable connector. pin 10 to pin 12. I always look for simple mods like this and try to record them. I haven't searched for it here - yet.

Three 1200XLs aquired last month in various states of dis-repair and missing parts. PCA logic parts replaced from scrap 600XL and parts I had on hand. Not so with keyboards, only one. All 3 Made in Taiwan. 1. 72R DA 14100 ?13 (last three washed out). PCA front: DA213 Rev A PCA rear: Mary 24 1983. Works, no keyboard, power LEDs and cart. port plastic and shielding. 2. 72R DA 04292 173 PCA front: DA 173 Rev A. Rear: XX Apr 1983 (Didn't want to take it apart again to see the day of the month.) 3. 72R DA 25959 253 PCA front: DA 253 Rev A. Rear: Jul 24 1963 B Missing top shielding. Now, where can I get two keyboards??? And a Cart. port cover? I received all three for work done to revive a dozen or so XF551's and a couple 1050's. PROM Ucode HYPROM A works great in the XF552's using SDX.

I have 4 or 5 XF551's with 3.5 DS/DD disk drives in them. Mostly TEAC FD235HF model drives. They are unmodified, still patched for DS1. HYPROM B Ucode. The only modification is on the J4 ribbon cable connector. The file going to pin 10 (DS0) has been cut off. A wire has been added from pin 12 (DS1) to the foil cut off of pin 10. With the HYPROM B Ucode they work beautifully with SDX , format to 2880 sectors, Ultraspeed. Question: Who came up with this Mod.? I've never seen it mentioned anywhere. The ones I have had bad soldering on the SIO interfaces and/or bad power connectors. I have 3 XF551's without a good Disk Drive. Been thinking of modifying one with a switch on J4 connector pin 10 and 12. Switch between 5.25 and 3.5 disks for testing. I understand that I would also have to swap the PROM, HYPROM A or HYPROM B.

Thank you. I'm a newbie here, don't know how to do the Quote. For the PROM burner update I only need the Ultimate.rom file, 512Kbytes.

Okay, I'm new to this. I have two Ultimate1M and one Super Cart. All I can do is write new FlashRAMs and install them in the units. Which .ROM file for the cart? I think I've found the one for the Ultimate1M. I know nothing about .ATR files and have no way of moving files from my PC to 8bit. I've been away from the Atari scene for 14 years or so. Just trying to get my retirement shop up and running.

Oops, found another white label on bottom of main board: Jun 26 1983 (& Handwritten 'B').

72 R DA 26153 263 Label inside DA 253 Rev. A Made in Taiwan, Mitsumi keyboard. 1996 I upgraded this machine to XE OS, Basic Rev C (Installed) and Antic C021697. I've been gone since 2006. Starting to dig out all my old machines and begin fixing them again.