For the next few weeks I want to spend some quality time with my real iron and spice up my working standard PEB (featuring TI 32K, TI serial, TI controller and a single TI SSSD drive).
Some immediate improvements would be to replace the noisy fan and to add a Lotharek drive to the box. Further down the road I also have a non-working US PEB I would like to run on 230 V. Much further down I might even tinker with some custom-designed expansion cards.
Now I'm a noob when it comes to the analog aspects of hardware, but the one thing I remember about the PEB is that it can provide only 1A of power safely. For running non-standard stuff, e.g., dual drives, one should do the 2A mod
. On the other hand, back in the day my original (and now lost) PEB did have two slim drives, and I doubt that the vendor applied this modification to the PEB.
Question 1. Will I be able to run the TI Disk Controller with a single TI SSSD Drive and the Lotharek drive (plus the other cards) safely together, or do I need the 2A mod? The 2A mod refers to the 12V line, but Lotharek uses 5V only.
Could I additionally power a standard 12V PC fan from the drive power line? This has been done
, but what about the 1A power limit? (On second thought: Papst 2600 rpm @ 1,3 W / 12 V = 100 mA, but Papst 1000 rpm @ 0,35 W -> 30 mA seems OK?)
For my broken PEB I would at the very least have to replace the fuse, which is hard to get at (rocker switch PEB). Worse, I need to handle 230 V. So I considered replacing the entire power supply with a modern PC one, knowing full well that this is obviously considered a bad idea
by several people
If I understood above articles correctly, the PEB requires 8V and 16V instead of the PC 5V and 12V, but all cards will do their own voltage regulation anyway and thus can handle 5V and 12V as well. I absolutely do not doubt these experts and their experience, but still ... When I look at the TI RS-232 interface card, which happens to lie on my table right now, it states as input power requirements
+ 7.5 TO + 10.0 VDC @ 0.600 AMPS
+ 14.0 TO + 18.0 VDC @ 0.100 AMPS
- 14.0 TO - 18.0 VDC @ 0.100 AMPS
Is it really
safe to run a PEB on 5V/12V?
Would that also solve the power (amp) shortage from above?
If I'm not mistaken, the (European) console power brick also delivers 8V and 16V.
Question 4. Couldn't you butcher something for the PEB out of that?
And if I ever get around to play with PEB prototyping
, I only have the "TI 99/4A and Peripheral Expansion System Technical Data" manual right now. According to that manual, a PEB card may draw up to 250/500/30 mA.
Question 5. So did I get this right that the 1 A limitation above only refers to the floppy drive power cable and that I could run up to 8 cards at 500 mA each on the bus? (If so the fuse part confuses me ...)
Question 6. Are there any other good resources for creating PEB cards? Are the schematics and/or sources for the PEB prototype board available somewhere?
Sorry, that's a lot of questions ... Have I already mentioned that I'm a power noob?