800XL PBI 5V fix?

[+MrFish]

8 minutes ago, x=usr(1536) said:

Absolutely.  I just find it interesting that Atari under Tramiel was every bit as capable as Warner-era Atari of making decisions that were, to be charitable, perplexing.

 

That's not to say that the Tramiels' decisions were all terrible; they weren't, and some are understandable given the state of Atari when they acquired it.  But more than a few babies were thrown out with the bathwater.

 

From all the interviews I've heard with Atari employees, I think it's safe to say that Atari never was a cohesive company; and I think its decision making was at least partly a symptom of that fact. 

 

[+mytek]

34 minutes ago, MrFish said:

Considering the ideas in the post of mine that I'm quoting here, it wouldn't have been short-sighted. It wouldn't have left the 1090 as the only way of utilizing the PBI for upgrades either; it just dictated that devices pull power from elsewhere.

I didn't expect to be taken quite so literally . What I really meant to say is that Atari was obviously 'influenced' by the 1090 being in the works, with its built-in independent power supply. And that it was 'short-sighted' to presume that all PBI peripherals would or should be done in this way. So bottom line, no allowance was made for a PBI peripheral to steal power from the Atari instead. By the time that 800XL was released, there were already other non-PBI peripherals that were stealing power without compromising the Atari, and with many more to come as the age of low power CMOS and microcontrollers were making inroads (SIO parallel printer, serial, and modem interfaces to name a few).

 

Now days we of course have multitudes of internal upgrades all working in harmony and all relying on the Atari computer's power supply.

 

Interestingly the PSU that came with the 800XL was rated for twice the requirement of the 800XL, being capable of 1.5 amps.

 

 

[+MrFish]

15 minutes ago, mytek said:

I didn't expect to be taken quite so literally . What I really meant to say is that Atari was obviously 'influenced' by the 1090 being in the works, with its built-in independent power supply. And that it was 'short-sighted' to presume that all PBI peripherals would or should be done in this way. So bottom line, no allowance was made for a PBI peripheral to steal power from the Atari instead. By the time that 800XL was released, there were already other non-PBI peripherals that were stealing power without compromising the Atari, and with many more to come as the age of low power CMOS and microcontrollers were making inroads (SIO parallel printer, serial, and modem interfaces to name a few).

 

Now days we of course have multitudes of internal upgrades all working in harmony and all relying on the Atari computer's power supply.

 

Interestingly the PSU that came with the 800XL was rated for twice the requirement of the 800XL, being capable of 1.5 amps.

 

Actually, devices drawing too much power from the computer may not have even been a concern for Atari; they may not have even cared what anyone else might want to do the PBI port; they could have simply been designing it with their own concerns in mind. So, in that sense, it could be seen as having been somewhat short-sighted.

 

I suppose, partly, it has to be considered from the standpoint that Atari was designing the replacement for the 800 to be cheaper, but they still wanted a means of adding upgrades in a plug and play manner. So, the 1090 was the external version of the 800's internal upgrade slots; and the PBI was probably not really seen as some playground for 3rd party developers, but rather a means of accomplishing their own goals.

 

[+kheller2]

The 1090 was a bit more than a 800 slot replacement.  The 1090 had the ability to use multiple 64K memory cards (one of which would take your 600XL to 64k) and it would also allow you to bankswitch another 128K (up to 192K).  In addition to the 80 column card, and the others.  Granted the 1090 doesn't have much logic on it.

[+kheller2]

On 11/14/2020 at 11:12 AM, mytek said:

The same mentality played into the decision to leave out the PBI on the 1200XL (which was present in the 1400 base design) - in order to save a few pennies in the short term, but to cut off the possibility to make more money after the fact by selling PBI peripherals to existing owners.

I'm not sure that is historically accurate.  The 1400 (as we know it 1400/1450 board) was not conceived before the 1200XL.  There were, as I recall, two competing 1200 designs, but neither had any of the bus logic that eventually become the PBI.  The PBI concept, I believe, did originate back in 82 but its hard claim it was the same thing.  Sweet8/LIZ NY did have a PBI and Porkey, but that was early '83 after the 1200XL had shipped.

[+mytek]

41 minutes ago, kheller2 said:

I'm not sure that is historically accurate.  The 1400 (as we know it 1400/1450 board) was not conceived before the 1200XL.  There were, as I recall, two competing 1200 designs, but neither had any of the bus logic that eventually become the PBI.  The PBI concept, I believe, did originate back in 82 but its hard claim it was the same thing.  Sweet8/LIZ NY did have a PBI and Porkey, but that was early '83 after the 1200XL had shipped.

You are correct, and I should have said the "Sweet-16" instead of 1400.

 

From Curt Vendel's Atari Museum website: Atari 1200 Prototype...

Quote

This is the actual PCB layout of the revision X8A PCB for the Atari "Sweet-16". This is where things get interesting. Click on the above image to examine it more closely... Note that the layout is entirely different from the production 1200XL computers. Take particular note of the upper right corner of this PCB design - there is a 50 Pin header footprint and the traces all lead to the major IC's on the board which means this was the very first PBI (Parallel Bus Interface) which appears to have been meant as an internal device interface versus the later XL designs which brought the PBI directly out of the system to an Edge Connector.

 

Not quite the same as what later became the PBI as we know it, but it had all the ear marks of what was to follow. The point is that if this had been released in the 1200XL, it could have set the standard for parallel expansion at the beginning of the XL line.

 

[+MrFish]

8 hours ago, kheller2 said:

The 1090 was a bit more than a 800 slot replacement.  The 1090 had the ability to use multiple 64K memory cards (one of which would take your 600XL to 64k) and it would also allow you to bankswitch another 128K (up to 192K).  In addition to the 80 column card, and the others.  Granted the 1090 doesn't have much logic on it.

 

I certainly didn't mean an exact one to one replacement. The 1090 just needed to at least cover what the 800's internal slots could do. But of course it made a lot of sense to bring more to the table with the 1090, from both an evolutionary and marketing standpoint.

 

[Faicuai]

 

On 11/15/2020 at 1:38 PM, kheller2 said:

The 1090 was a bit more than a 800 slot replacement.  The 1090 had the ability to use multiple 64K memory cards (one of which would take your 600XL to 64k) and it would also allow you to bankswitch another 128K (up to 192K).  In addition to the 80 column card, and the others.  Granted the 1090 doesn't have much logic on it.

 

Well, what's really ironic is that, by the time the 1090 design and specs were finalized and some units built, there was $4000-$7FFF and $C000-$CFFF bank-switching, >= 128K AXLON ram expansions, multiple / simultaneous 64 KB ram boards (up to 192 KB courtesy of MOSAIC) and several 80-cols boards (Bit3 Fullview and Austin Franklin), all already available for the 800, internally-fitted, and with plenty of DC-power available in all slots (-5, +5 and +12 v dc)... And all of this without a PBI-bus and an odd-shaped external "juke-box" which form-wise negated the design-aim of the XL-case itself !!... and without mentioning that the 800 bus-logic control layer that was clearly more primitive than the one designed for the XL-series (where, together with a "thinner" footprint was the real gain in the XL design, since most of the rest was a step backwards, architecturally, let's be honest).

 

I personally think the PBI-bus itself and the incoherent (form-wise) 1090 were the result of having to accept that Atari could not reach the position Apple had in the market, commanding similar gross margins ($), thus being forced to produce things cheaper, even if it meant introducing the 1200XL that essentially and fully negated the more robust and open architecture of its predecessor.

 

In contrast, Apple never compromised the Apple II architecture, maintained its form-factor and original appearance,  all the way to its "last mohican" (Apple IIe Platinum), and in parallel, attempted to create a "portable" life for the series, with the introduction of the IIc (with which you could never build the kind of systems that you could with the Apple II, but was very well fitted, and you could take it to many more places, and would also be a better fit for schools, etc.) 

 

Having said all of the above, there are about four (4) unused pins on the original 800XL PBI bus design, IIRC. As a consumer, I would be in favor of a contemporary, consensus-based approach (between top HW and low-level SW developers of our community) to modernize the bus itself, thus enabling the creation of something much better than the 1090, and capable of running external GPUs, co-processors, etc., and all this with minimal modifications of XL-host, so the entire community enjoys the XL-promise to its full potential, and with a new lease in life.

[Tillek]

On 11/13/2020 at 7:12 PM, MrFish said:

I just opened up my 800XL and snapped a shot. The 5 volt mod is the yellow wire, obviously.

 

 

Sorry to necro bump......

What gauge wire did you use on this?  Planning to do it with 20AWG tomorrow (for IDE 2.0+, the one with the built in CF adapter).  I figure that is fine since many CF adapters use the floppy power connector and they use 20 (vs. 18 for the HD power connector).

 

 

(Not looking for guesses, but responses from people who did this successfully....)

[+MrFish]

8 hours ago, Tillek said:

What gauge wire did you use on this?  Planning to do it with 20AWG tomorrow (for IDE 2.0+, the one with the built in CF adapter).  I figure that is fine since many CF adapters use the floppy power connector and they use 20 (vs. 18 for the HD power connector).

 

(Not looking for guesses, but responses from people who did this successfully....)

I'm not sure exactly. It was quite a while back when it was done. By the looks of it, seems likely I used a spare PC power supply extension connector (hard disk, cd-rom -- molex-type) for usurping the wire.

 

[Rybags]

You don't need thick wire.  I'm fairly sure I've used thin monocore on some things.  Generally your external PSU will be rated somewhere 1.2 to 2 Amps.   A standard PBI device such as IDE+ 2 will probably pull half an Amp.  Of course it's probably not a good idea to try and power a mechanical HDD as well this way - you'd likely want a seperate PS in that case.

The wire I used for my PBI is barely thicker than what you might see for a joystick line.

Edited February 12, 2022 by Rybags

[BillC]

8 hours ago, Rybags said:

Of course it's probably not a good idea to try and power a mechanical HDD as well this way

Many older 2.5" IDE HDD are rated ~1A. I have a 2002 Travelstar 4200rpm drive that is labeled 5V@1A and also a 2006 Travelstar 5400rpm drive that is labeled the same, it seems likely the manufacturers increased RPM or storage size to stay ~1A. As long as an adequate +5VDC power supply is used, I would recommend 2.5A minimum for use with an IDE+ 2.0 and a 2.5" IDE HDD, it should be fine.

[invisible kid]

Hey, I was going to give this a shot. Thanks for providing the info and pic! My skills aren't too strong. I foresee myself having difficulty attaching 1 wire to the two pins. Would it be better for someone like me to run two wires or is it worth it to learn to finesse with only the one wire. I feel like if I try that it will come loose in like 10 years if it's not stabilized by a through-hole.

Edited July 12, 2022 by invisible kid

[invisible kid]

I am going to explore further if I can attach the wires to a more newbie-friendly place. Perhaps trace the leads for 49 and 50 back to an easier spot, but I am thinking they probably don't go anywhere since they aren't used at all? Since I am a functionalist I am thinking of running the new 5v + gnd wires out of the back of the 800xl and wiring it directly to the attached device, but with connectors inserted in-between to make it easily disconnect-able.

 

Gonna chew on it for awhile.

 

I suppose drilling holes in the 800xl PCB would be ill-advised.   : D

Edited July 12, 2022 by invisible kid

[reifsnyderb]

+5vdc needs to be on pins 47 and 48.  

 

Mapping the Atari shows a question mark but it's been confirmed that pins 47 and 48 are with the 600XL and a modified 800XL.

 

https://www.atariarchives.org/mapping/appendix14.php

 

Edit to add:  If you are thinking about adding +5vdc for the 320k PBI board, adding +5vdc to either pin 47 or 48 will be fine.

 

Edited July 12, 2022 by reifsnyderb

[invisible kid]

Oops yes, 47 and 48 I meant.

 

But if I wire directly i would just take 5v and gnd and connect it directly to the device. There is already through holes to attach there, which is better for a newb like me, even though they are very small.

 

I know this would be ugly, but if it has a better chance of holding up for 20+ years I'll do it.

Edited July 12, 2022 by invisible kid

[+MrFish]

I just had a closer look at my machine (a little hard to tell exactly from the pic); as I suspected, I'm only attached to pin 47.

 

[reifsnyderb]

14 minutes ago, invisible kid said:

Oops yes, 47 and 48 I meant.

 

But if I wire directly i would just take 5v and gnd and connect it directly to the device. There is already through holes to attach there, which is better for a newb like me, even though they are very small.

 

I know this would be ugly, but if it has a better chance of holding up for 20+ years I'll do it.

On the left side of the component side of the PBI board there are 2 holes and some notation that they are for +5VDC.  You can run clean +5VDC into the board by soldering 2 wires there.  The jumper, on the back, has to be set to "external" to use those holes.

[invisible kid]

Thanks, I think that's the route I will go. It's basically the joystick port fix but transferred from the joystick port to wires to/from the pcb.

Edited July 12, 2022 by invisible kid

[+scorpio_ny]

2 hours ago, invisible kid said:

Thanks, I think that's the route I will go. It's basically the joystick port fix but transferred from the joystick port to wires to/from the pcb.

Here is a YouTube video showing @flashjazzcat soldering the wire for the PCB 5V. I will probably go this route since it looks simple.

Edited July 12, 2022 by scorpio_ny
Add YouTube link

[invisible kid]

So just to double-check before it goes under the knife. I need clean 5v and ground from MB. I am going to take the 5v line from the node in MrFish's pic. And I am going to take ground from pin 1 of the PBI since its' the closest to where I want it to go. If anyone notices flaws in that approach, please let me know.

[+scorpio_ny]

22 minutes ago, invisible kid said:

So just to double-check before it goes under the knife. I need clean 5v and ground from MB. I am going to take the 5v line from the node in MrFish's pic. And I am going to take ground from pin 1 of the PBI since its' the closest to where I want it to go. If anyone notices flaws in that approach, please let me know.

I think you are only need to supply the 5 volts. The PBI already has ground. In the link of the video I posted, there was only one wire soldered in.

[reifsnyderb]

11 minutes ago, scorpio_ny said:

I think you are only need to supply the 5 volts. The PBI already has ground. In the link of the video I posted, there was only one wire soldered in.

Good point.  Since you are using the 5 volts from the Atari, you don't need to connect the ground as it's already there.  

 

Personally, if I were to be modifying my 800XL, I'd do the internal mod just like MrFish's pic.  That way there aren't any external wires.

[invisible kid]

31 minutes ago, scorpio_ny said:

I think you are only need to supply the 5 volts. The PBI already has ground. In the link of the video I posted, there was only one wire soldered in.

Sweet! Less chance to screw something up, thanks.

 

19 minutes ago, reifsnyderb said:

Good point.  Since you are using the 5 volts from the Atari, you don't need to connect the ground as it's already there.  

 

Personally, if I were to be modifying my 800XL, I'd do the internal mod just like MrFish's pic.  That way there aren't any external wires.

Yes, I am only changing up the strategy due to my skill level. I am trying my best, but am probably leaving cold solder joints in my wake. I feel if I solder a wire to a trace, it will lift off after a short period of time. I think folks like MrFish and flashjazzcat and you have the expertise to do it solidly where it will last a long time.

 

But I might try it because if it falls off it isn't the end of the world, but a future owner might not know where the wire came from if it fell off, but maybe I shouldn't worry about that.

 

Thanks for the input you guys.

Edited July 13, 2022 by invisible kid

[reifsnyderb]

Just now, invisible kid said:

Sweet! Less chance to screw something up.

 

Yes, I am only changing up the strategy due to my skill level. I am trying my best, but am probably leaving cold solder joints in my wake. I feel if I solder a wire to a trace, it will lift off after a short period of time. I think folks like MrFish and flashjazzcat and you have the expertise to do it solidly where it will last a long time. But I am considering it because if it falls off it isn't the end of the world, but a future owner might not know where the wire came from if it fell off, but maybe I shouldn't worry about that.

 

Thanks for the input you guys.

Practice on something "expendable" first.  The real trick to soldering is that you don't heat the solder.  You heat what is being soldered and the solder will melt to it.  Also, "tin" the soldering iron by melting just a tiny bit of solder on the soldering iron.  This helps the heat conduct.