Ksarul

You might want to look at the drive belt on your disk chucker to make sure it isn't slipping. You know that several portions of the disk drive are working: the sensor for the disk timing hole, the stepper motor, and the motor circuit. You also know the drive selection circuitry is correct, since it is doing all of the above mentioned things when you try to select it. If the belt is deteriorated/slipping, it may just not be finding the initialized sector zero to write the header information to. Another note: there is a timing wheel on the spindle--these sometimes fall off over time (I have a drive like that). The drive doesn't use it for normal operations, but it is used to calibrate things.

That is good. The cartridge may fit, but it has a completely different pin-out. I suspect it might just destroy both cartridge and the Tutor if you turn it on. . .

Harald Glaab or Michael Becker are probably the best people to answer this question, but neither of them is active on this forum. You might want to tr and ping Harald at the SNUG mailbox. . .

One note, based on the physical jumpers, your Drive 0 (1) does NOT have HS jumpered. Look carefully and you will see that the center of the strap seems to have been cut. I just looked in the manual at page 3-2 for the usage of these drive shunts. A drive should use HS or HM, but not both at the same time, which is why Drive 1 (2) stops working when you add HM. I suspect your current problem is actually partly due to the way you have Drive 0 (1) selected, which works fine if you only have one drive in the system. Using the HM shunt turns on the solenoid for the drive whenever the motor is turned on--and all drive motors are turned on at the same time, so you may now have the solenoids on both drives pulling down the write current when you try to select drive 1 (2). It is generally not a good idea to have the heads selected using different means on different drives. I pulled open one of my original TI MPI-51 drives to verify that the default TI shunt settings were what I remembered them to be, and they were: Jumpers for HS and DS0 are the standard settings used by the TI, so do not use HM. If you don't have any of the purpose-built shunts with the right configuration, you can just bridge the two necessary shunts with clipped-off resistor or capacitor leads. . .as long as they fit snugly into the dual-wipe socket, you should never have any problems there (I have drives that I have used that way for much of the last 40 years). Here's the MPI 51/52 manual for you. Disk Chuckers rule! Actually, if you do some creative positioning with the jumper blocks you do have, you can set them properly in your Drive 0 (1). Move the shunt connecting the pins for DS0 to HS (with the current HS pins hanging over the board and not in the socket) and then move the shunt on HM to the DS0 pins and you should be good to go. . .and your setup would actually require a termination resistor in both drives, as each drive is on a different connector on the disk controller. Your Drive 0 (1) is on the internal connector (the 34-pin header connector) and your Drive 1 (2) is on the IDE connector at the back of the card. A configuration like this is the only time you need two termination resistors (and if you have multiple drives on each connector, then just the last drive of each chain needs one). micro-peripherals-model-51-52-flexible-disk-drive-manual.pdf

Yet another Mitsumi keyboard for a laughable price. . .

Not only is the price insane, but it is a Mitsumi keyboard, so it has about a 95% chance of not being even remotely functional. . .

Your comment is not so far from the truth as you might imagine, @OLD CS1. LOLOL

Definitely quite a few interesting items in the lot. The Editor Assembler keyboard template for the 99/4 is definitely on my personal want list, as are a lot of the DataBiotics cartridges and the odd little Navarone cartridge sitting above the Super Demon Attack cartridge in the cartridge case in the 12th picture. . .

Note: or single sided single density disks, if your floppy drive happens to be one of the original TI drives (MPI-51 or Shugart SA-400). Total storage per disk would be 90K with single-sided drives or 180K with double-sided drives. Disks to go with them can be SSDD or DSDD (only format the SSDD disks as single-sided, but double-sided disks can be formatted to use only one side). Most disks you find will be the double-sided ones. If you ever get your hands on a double-density controller (CorComp, Myarc, BwG, Atronic) your disk capacity would double when using the same drives with disks formatted to double-density.

It is an HRD1000, as @Schmitzi noted and based on the serial number. One of these two manuals should match the specifics of the board, with the HRD+ manual being the most likely direct match. HRD Reference Manual - Booklet.pdf HRD+ Ramdisk.pdf

I think that is the modification that everyone used for these cards BITD.

I know from experience what that particular mistake will do. I was sorting parts for the first batch of UberGROM boards I built and misread the value stamped on a bag of capacitors. I built ten boards with .1uF capacitors where the 1nF capacitors belonged and none of them worked. I spent a couple of weeks troubleshooting, and one day when I was looking for bad solder joints/shorted traces with my magnifying glass one of those capacitors came into my field of view and I had my facepalm moment. .1uF does not equal 1nF. I changed them out and the boards all started working. . .BTW, getting the 32-pin PLCC sockets into those holes can sometimes be a bit fiddly, especially if one or more leads is just slightly out of alignment. I usually look at that before I put them in and gently straighten the misbehaving pins, if needed. Another trick is to install the jumper block on the RA pin pair in the lower right corner of the board before you solder it into place, as you won't have issues squeezing it past the other components that way. Note the pads near that pair as well--if you attach wires and a push-button switch to them and mount it into the cartridge case, you now have a reset switch. You do need to remove the jumper block from the pins if you do this, but it is a neat little board option originally suggested by @acadiel.

Been looking for that one for a long time. I haven't found anything except for some of the manuals (that's where the GPL manual came from, although it was one of those manuals that spread all over the world like wildfire BITD as a set of mostly horrible photocopies that I typed in manually to get a good copy (Rich Gilbertson also typed in his copy for the same reason)).

Looks like I need to make a test cartridge. . .

I think the lowest score that either of you posted exceeds my lifetime high score at this game @Smoker Ace and @jwild. Press on--it is good to see people faring much better with this one than I did BITD.

Mike Wright requested that things pointed to his CADD site for things that he made available online. The community generally respected that request, although if his site is truly down, the topic may need to be revisited. I think I still have an email address that can get to him. I'll see what I can dig up.

The version @hloberg found was written by Thomas Weithoffer, IIRC. I think I saw somewhere that he passed away at age 22 from cystic fibrosis. Much too young for such a talented programmer to go. . .

My suspicion is that the software doesn't expect disk drives greater than DSK3. . .anything greater than that would probably error out.

He also bought the final stocks from Ramcharged Computers and LL Connor. There may be others to add to that list. . .

One note. There is a general test you can perform to verify that the PEB isn't defective. First, power it on. You should hear a loud fan sound. This verifies that your line voltage is making it into the PEB (mains fuse is good). Turn it off, wait a couple of minutes and insert the Flex Cable card. Plug the Flex Cable into the side of the TI, turn the PEB on and then turn on the computer. If the indicator light in the slot with the Flex Cable card lights up, the PEB voltages supplied to the bus are making it through the transformer (no blown transformer internal fuse). If this works, your PEB is generally good. You may still have some corrosion on card connectors or a random bent connector pin, but the PEB is definitely functional. No other cards are necessary for these tests.

I'll look to see if any of my 16V8s are handy (I think I may have a 2793 card--I'll have to verify that first) and try to burn one.

Minor voltage output level differences between the two chip types. One (the one with slightly lower outputs) may be being drawn below the level of efficacy by a partial short, while the one with slightly higher outputs may ave just enough residual power to mostly work.

One other thought here--you may have a trace somewhere that is making a bad connection (might even be connected, but not well enough to carry sufficient current) or you might have a partial or complete short between pins somewhere on the board that is pulling a signal lower than it should be or combining two signals that generally need to be separate. The intermittent nature of your observed problems tends to point me this way. . .

I use a BK Precision 844USB for most of the truly ancient chips, as it supports just about everything from 2508 to 2564, as well as 2708 to 2764 chips. I've even gotten it to work fine with 512k x 8 Fujitsu 27C4000 chips using a 27C4001 adapter--a seriously heavy lift, as none of the rest of the dozen or so programmers I have can do that. Downside is that it is relatively expensive new ($500+)--and recently discontinued, so the only options are now used.

Also note, if you are trying to install updated EPROMs into the CC9900 Micro Expansion System, it is a different set of EPROMS and it does require desoldering/socket installation. This mod just skips the CorComp power up routines to increase compatibility and doesn't add the MG enhancements.