Stuart

That seems to work OK. Thanks for the padding.

Other way round. Data goes through the LS245 as it is bidirectional. Address and control lines go through the LS244s as they are unidirectional.

I've updated the Cortex BASIC program so it should now work in 80 column text mode on a 4A with the F18A. I've tested in Classic99 - anyone able to test on the "real iron" to save me having to dig my console out and strip it down? Zip file attached with: -- 40 and 80 column versions in TIFILES(?) and TiDisk formats. Should load with E/A option 3. -- 40 and 80 column versions in binary format for burning to EPROM for a Guidry 64K cartridge (32K 27[C]256 EPROM and a 74LS379 ). Program details here BUT I haven't updated the disk download on this page yet until I know the 80 column version works - use the zip file attached below: [http://www.avjd51.dsl.pipex.com/ti/ti.htm#programs]. Cortex BASIC 40 and 80 Column.zip

Hmmm ... is it possible that the US versions are fixed at 110V, whereas the European versions can be switched between 110V and 220V? The Peripheral Expansion System technical data manual clearly shows "-1" and "-2" variants of the power supply.

If you buy a can of capacitor smoke off eBay you should be able to pour it back in to repair it.

Should work OK with the nanoPEB, as that is what I used when I wrote the program. I suspect that if you get the MiniMem battery sorted so that it saves/loads in BASIC, then the LBLA and Lines programs will work OK as well. Stuart.

Also try: after loading MM_LINES or MM_LBLA, there should be an option 4 which resets the console. Don't remember if resetting it that way was important or not, but you might want to try it just in case. Stuart.

Only thing that springs to mind - for the first two tests, did you actually power-off rather than "quit out"? If your MM battery is dead, then you would lose the program you just loaded. If you really did "quit out", is your series of tests repeatable - does exactly the same thing each time you try it?

I expect the circuit schematic, PCB layout, firmware and software will be made available, and maybe a run of PCBs made if there is the interest. But that's all a long way off yet. I haven't heard of any dates yet.

Being looked at I believe for the next generation (or maybe the one after that) of the Mini-Cortex system, which you can read about here: [http://atariage.com/forums/topic/238752-ot-mini-cortex-board/?hl=%2Bmini%26amp%3B%238208cortex&do=findComment&comment=3245612].

If it's beeping from the moment you apply power to the moment you switch if off, that's a console problem - it's not booting and the sound generator isn't being switched off. First thing you could try is strip down the console (see [http://www.mainbyte.com/ti99/console/console_dis.html] if you're not sure how to) and remove/reseat the 6(?) socketed chips. That might just sort it. If that doesn't help, then might be easiest to get a 'new' console off ebay.

If you put the box as you had in your photo earlier, with the cable on the left and the silver Astec modulator on the right. There is a group of 4 ICs on the PCB. The bottom right IC should be labelled LM1889. Check the voltage between the 5th pin down from the top left of this IC(-ve) and the pin directly opposite that on the right hand side (+ve). You should get around 12V. Also, are you testing this on a 'modern' TV or an old analogue one? The modulator output frequency may well have drifted over the years and a modern TV won't lock to it, but an old analogue one will. Stuart.

With the DIN connector on the 'computer end' of the modulator cable, you should be able to slide the plastic sheath back (might be a metal tab that you have to push back into the connector slightly) and separate the two halves of the connector shell. You can then check if any of the signal cables has broken from the connector pin. Also look at the connector pins and check if they are badly tarnished so not making a good connection. Might be the case if the computer hasn't been used for years. If you've got a multimeter then I can tell you which pins to test to check that you've at least got power getting to the modulator board. Stuart.

Worth noting that if you do plug the cable in round the wrong way, it shouldn't damage anything - the drive will just spin continuously as soon as you apply power.

The modulator instructions I used were from a Danish website, with the original apparently coming from the TI-Revue magazine. The website is no longer active so I've attached a scan of the printout I made years ago. I built my buffer circuit on a small piece of Veroboard, and fed the composite output directly on a length of coax cable rather than fitting another connector to the modulator case. I didn't bother with the audio output as I have a speaker in my console case. I also took the composite feed from the video input to the modulator block, rather than from the capacitor shown in the article. ==== You want a 992*8* to give you a 60 Hz output, I believe.

The 9928 has the same luminance and 2 x colour difference signals as the 9929. So you'd still need some sort of modulator/encoder to combine them into a colour composite signal. The PAL modulator *might* work as you pick out the signal before the actual modulation stage.

If you're starting with a US console, then there are two links that you'd have to swap to route the two colour signals to the rear connector. You'd then need to connect a PAL modulator to combine them. If you've got the version of the modulator in the metal case, then you can pick off a colour composite signal inside the modulator, buffer it with a small circuit on a piece of veroboard (a couple of transistors, caps and resistors) and use that to drive a colour monitor. (Probably possible as well with the modulator in the plastic case but I don't know where in the circuit to tap into). If you've got a copy of the console schematic (on the FTP site) you can see the VDP output circuit and the various links.

With the 9918, the colour mixing is done internally in the chip and it has just one video output. With the 9929, it outputs a luminance signal plus two colour difference signals, and the colour mixing is done in the external modulator. There are a couple of links on the motherboard that have to be swapped when switching between the two chips (probably a different crystal as well). So it sounds like you're just using the luminance signal which gives a greyscale output. Might be because someone has put a 9929 in a US console (which had a 9918), or you're not using the modulator (are you connecting directly to the back of the console?), or the modulator is faulty. Or possibly something else!

I think your last sentence sort of sums it up - you might be able to get CP/M to 'boot' as it were on the 9900, but there are no programs that will actually run on it as they're all written in Z80 or 68K machine code - or have I got it wrong somewhere?

There's a manual for the FDD200-5 included as section 3 in this document: https://cache.industry.siemens.com/dl/files/472/23842472/att_77309/v1/PG670_Betriebsanleitung_e_OCR.pdf If you want just that section pulled out into a separate PDF, let me know and I'll do it, if you can't.

You can add for compatible 40-track drives the Siemens FDD200-5.Full height, 48 TPI, DSDD.

It's a TMS99000 according to: [http://www.textfiles.com/bitsavers/pdf/ti/990/990-10/2302633A_990-10A_GenDescr_Feb84.pdf] section 1.3.1 [http://www.textfiles.com/bitsavers/pdf/ti/990/990-10/99010A_paper_Apr83.pdf] page 2, 3rd para

Sounds a similar length to my cable. So formatting a disk with Disk Manager gives error 38? Is that actually a valid error number? What happens if you try to do a simple SAVE from BASIC to a formatted disk?

How are you powering the FDC card? Are the voltage regulators still fitted? If yes, might be worth removing them and feeding the regulated power directly to the card, see if that makes a difference (triple-check the power connections before switching on without the regulators!). Have you got a 5 1/4" drive you can test with? [Clutching at straws here!]

You're testing with the same cable between the FDC and the drive as well? Good solid earths between everything?