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PEB power questions


ralphb

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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). :pirate:

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.
Question 2. 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

.

Question 3. Is it really safe to run a PEB on 5V/12V? :-o 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? :)
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I recently put in a 12v fan in the PEB following the instructions on mainbyte. I'm not sure why they don't have you just use a wiretap connector and take from the 12v lines to the floppy bay.

 

It looks like you've done the math on how much power the fan uses, and concluded you'll be fine.

 

Somewhere else here, someone commented that the drive motors are never both active at the same time, making the multi-drive power concern generally unwarranted. And then solid state drives like the Lotharek or Gotek units, just aren't going to be drawing as much as an old full-height TI 5-1/4" drive.

 

I'm not anything like an expert here, but I had the same impression regarding expansion cards and their power source not being the 12v used for the drives.

 

I seem to remember there were 4 power levels available in the PEB, and most cards have a regulator to get the >5v source down to 5v. Cards like the RS232 may have a different signal level on the external interface, and so they grab one of the higher lines and bring it down... So I had the impression that if a card wanted 12v, it took the ?16v? source and used a regulator for it.

 

And I know a million years ago, we (the folks on the Kitsap peninsula) never did any PEB power modding to run multiple 1/2 height 5-1/4" drives. But for reasons I no longer remember, we always ran TEAC drives.

 

My answers are mostly conjecture, I'd love to hear some facts as well...

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Schmitzi has a listing of compatible drives in his fantastic thread << HERE >>

 

If I may make a suggestion... you cannot go wrong with 3.5's and if you get the right ones, you'll be able to 'grow into them' as you expand your system later if you decide to go with the 80 track mod or a different controller.

 

I ran two of these in my P-Box until recently with no problems at all...gallery_35324_1027_112964.jpg

gallery_35324_1027_117389.jpg

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Thanks for the comments about dual drives, but let me rephrase my main question(s): How much power can I draw safely from

  • the bus
  • the 12V floppy power cable
  • the 5V floppy power cable

all at the same time? Is it 1 A combined, or more?

 

(BTW, 3,5" drives are a no-go for me personally -- for retro they don't quite match the original time period, and for convenience they simply don't offer any. Of course, YMMV.)

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The only thing I could find is this (from the PEB&Console´s technical data)

My question would be, if this 110V-mod is OK for a 220Volt-PEB, too...

 

 

 

post-41141-0-33278600-1448398255_thumb.jpg

 

 

PS: The "Using 12V/5V INSTEAD of 15V/8V"-question was answered to me for severeal times with:

if you take a PCs powersupply this is OK (I wanted to place the backplane in a PCs housing)

 

for example, The Great Gazoo´s PC-Housing for the PEB´s backplane worked without problems for over years

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The only thing I could find is this (from the PEB&Console´s technical data)

My question would be, if this 110V-mod is OK for a 220Volt-PEB, too...

 

 

 

attachicon.gifPEB-Power1.JPG

 

 

PS: The "Using 12V/5V INSTEAD of 15V/8V"-question was answered to me for severeal times with:

if you take a PCs powersupply this is OK (I wanted to place the backplane in a PCs housing)

 

for example, The Great Gazoo´s PC-Housing for the PEB´s backplane worked without problems for over years

I too have used a PC power supply without problem for all the time that I have had a functional TI or Geneve. Even now the PEB Box I am using has a switching power supply in it.

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Yes, thanks, so one man more telling me that it worx :) But, I am still hesitating haha ;)

It is hard to believe, and you can also find a discussion here on AA about modifying the PEB-Cards for this power-scenario here,

but at the end it is NOT needed.

 

Alle people are telling so. Yes, I should do it :) Next cool BigTower-Housing is mine, for the Geneve.

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Yes, thanks, so one man more telling me that it worx :) But, I am still hesitating haha ;)

It is hard to believe, and you can also find a discussion here on AA about modifying the PEB-Cards for this power-scenario here,

but at the end it is NOT needed.

 

Alle people are telling so. Yes, I should do it :) Next cool BigTower-Housing is mine, for the Geneve.

One of my Geneves, when I get it functional again, will be dwelling in a Dell server case with the existing power supply on a Rave 99 motherboard, with an included TI99, sitting beside it. ;)

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.

 

nice :) hmm, Geneve with a Rave99-Motherboard ? I only know about the keyboard-extension-board for the TI´s console,

but how to combine the TI-Console with a Geneve in a PEB (here: in a PCs housing) ?

 

------

 

 

I will watch out at the workshop for a nice big housing. or maybe eBay.

Would you prefer AT or ATX-Powersupply ?

 

But it is sooo strange that it runs with 3 Volts less on both voltages.........

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ah, the PE/2-housing ? (sorry, my only pics)

 

post-41141-0-10801700-1448411065_thumb.jpg post-41141-0-74318800-1448411066_thumb.jpg

 

 

some power-info:

 

post-41141-0-72080300-1448411202_thumb.jpg

 

 

 

 

uih, different models ? data for the list. as I never realized that :)

 

post-41141-0-64560100-1448411307_thumb.jpg

 

/EDIT: done :) / post-41141-0-88420400-1448412415_thumb.jpg

 

 

 

 

ah, and this explains why the PEB with a PC-powersupply can fire the cards:

The voltage-regulation-modules (VRM) are on EACH TI-PEB-card (almost using 12 Volts),

and so the PEBs PSU can fire with more volts. In the case of a lower power (PC-PSU))

the VRMs on the PEB-cards maybe just will "sleep", or just "bypass".

 

post-41141-0-73101300-1448411647_thumb.jpg

 

 

 

post-41141-0-21949700-1448411863_thumb.jpg post-41141-0-95526400-1448411865_thumb.jpg

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The rave system had you take the motherboard from the console and house it inside the new box as well. I remember this because a member in the vast group here in Phoenix had one. It seems I was over there fairly often because the thing was a bit flaky. I wish I would have nabbed it from him however.

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