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HP Portable Plus?

smp said:
Since I have not attempted to disassemble the system, I'm not certain how big of a job it will be to get to the motherboard and perform this replacement.

smp
Click to expand...
I haven't had it completely apart, but from what I did disassemble it looks really nice to work on.
 
Yup, you're right U20, 74HC14 gets its input through a rather odd configuration, where each input pin is tied to ground via a 4.7K resistor and then coupled to the inputs of the HC14 through a 470K resistor. Pretty shoddy for HP and the HC14 is probably what's gotten zapped. Almost certainly, the configuration does not meet the EIA RS232C standard.

I suspect that the high-value input resistor also limits the highest speed at which the serial port can operate.
 
Chuck(G) said:
Yup, you're right U20, 74HC14 gets its input through a rather odd configuration, where each input pin is tied to ground via a 4.7K resistor and then coupled to the inputs of the HC14 through a 470K resistor. Pretty shoddy for HP and the HC14 is probably what's gotten zapped. Almost certainly, the configuration does not meet the EIA RS232C standard.
Click to expand...
Well, they do claim that:
The computer operates as a Data Terminal Equipment (DTE) on its serial interface. The interface complies with the following industry standards:
• EIA RS-232-C. Electrical specification (except that a 9-pin female connector is used instead of a 25-pin male connector).
• CCITT V.28. Electrical specification.
• CCITT V.24. Electrical specification (for the nine implemented lines).
Click to expand...
I think one of the reasons for the non-standard interface may be to allow shutting down the interface to save power while still being able to monitor it in order to wake up the computer; also it looks like the logic is also shared with the HP-IL interface.
 
smp said:
...The good news: Everything that I type on the HP system shows up just fine on the Dell laptop Hyper-Terminal.

The bad news: Nothing that I type on the Dell Laptop in Hyper-Terminal shows up on the HP system.

BAH!

I have tried everything that I can think of. I have the HP system users manual and I have tried and re-tried all the settings. The fact that I have a good path from the HP system to the Dell Hyper-Terminal tells me that I am wired up correctly. But, nothing that I have tried makes anything come through on the HP system side.

Double BAH!

I am coming to the conclusion that the HP system may be broken on the serial I/O receive side.

Does anyone out there have any thoughts or ideas to offer?

Thanks!

smp
Click to expand...
It's certainly possible that you have a hardware problem, but I'd double-check your connections first, just in case; RS-232 can sometimes be confusing, especially with non-standard connectors, and that it works in one direction doesn't really guarantee that it's correctly connected and/or configured.

I set the parameters at both ends to 19200bd, 8 bits, no parity, XON/XOFF, and it worked first time, no problems; here's how I wired the cable, a normal full null-modem adjusted for the HP's pinout:

HP ---- PC
DTR-1 1-DCD
DTR-1 6-DSR
TXD-2 2-RXD
RXD-3 3-TXD
RTS-4 8-CTS
CTS-5 7-RTS
DSR-6 4-DTR
GND-7 5-GND
DCD-8 4-DTR

Hope it works for ya!
 
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MikeS said:
Well, they do claim that:
Click to expand...

Read the EIA spec carefully and note what voltage levels are specified for mark and space. Then observe that with their 74HC14, everything from V[sub]IL[/sub] will be treated as a mark, which, according to IBM:

The signal is in the mark state when the voltage on the interchange circuit, measured at the interface point, is less than -3 V dc with respect to the signal ground. The signal is in the space state when the voltage is greater than +3 V dc with respect to the signal ground. The region between +3 V dc and -3 V dc is defined as the transition region and is not a valid level. Voltage less than -15 V dc or greater than +15 V dc is also not a valid level.
Click to expand...

I'll check my manuals, but I'm relatively sure that LTC offered a low-power EIA receiver back then.
 
Chuck(G) said:
Read the EIA spec carefully and note what voltage levels are specified for mark and space. Then observe that with their 74HC14, everything from V[sub]IL[/sub] will be treated as a mark, which, according to IBM:



I'll check my manuals, but I'm relatively sure that LTC offered a low-power EIA receiver back then.
Click to expand...
Well, yes; there are standards and there are standards, and luckily there are so many ;-) ; anyway, let's hope it's just a cabling or config issue in this case.
 
MikeS said:
It's certainly possible that you have a hardware problem, but I'd double-check your connections first, just in case; RS-232 can sometimes be confusing, especially with non-standard connectors, and that it works in one direction doesn't really guarantee that it's correctly connected and/or configured.

I set the parameters at both ends to 19200bd, 8 bits, no parity, XON/XOFF, and it worked first time, no problems; here's how I wired the cable, a normal full null-modem adjusted for the HP's pinout:

HP ---- PC
DTR-1 1-DCD
DTR-1 6-DSR
TXD-2 2-RXD
RXD-3 3-TXD
RTS-4 8-CTS
CTS-5 7-RTS
DSR-6 4-DTR
GND-7 5-GND
DCD-8 4-DTR

Hope it works for ya!
Click to expand...

Hi folks,

Thank you very much for keeping up the drum beat of advice to keep checking on the cabling!

Last night I got the chance to buzz out my "RS-232" cable, and to my surprise, it isn't a null modem RS-232 cable at all, it is simply a straight through, pin 1 to pin 1, pin 2 to pin 2, etc. cable!

So my effort with this cable is void. I'll have to re-wire it and try again.

Again, thanks very much for keeping after me.

smp
 
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smp said:
Hi folks,

Thank you very much for keeping up the drum beat of advice to keep checking on the cabling!

Last night I got the chance to buzz out my "RS-232" cable, and to my surprise, it isn't a null modem RS-232 cable at all, it is simply a straight through, pin 1 to pin 1, pin 2 to pin 2, etc. cable!

So my effort with this cable is void. I'll have to re-wire it and try again.

Again, thanks very much for keeping after me.

smp
Click to expand...
It's a very non-standard cable; ironically a straight cable is actually closer than a null-modem in this case since the HP's DE9 pinout corresponds almost exactly to a DTE DB25, which in turn has pins 2 and 3 crossed over from a 'normal' DE9. If it weren't for the different signal ground pins (7 vs. 5) connecting 2 to 2 and 3 to 3 would probably work.

Edit: Just tried it and it works fine; configure the port to ignore CTS, DSR and DCD and use XON/XOFF, and just connect:

HP - PC
7 --- 5
2 --- 2
3 --- 3

FWIW, although I do have various RS232 break-out boxes and even an HP analyzer, for stuff like this I prefer this; just a straight-through cable cut in half with header plugs added:

HPrs232.JPG
 
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MikeS said:
So, how'd you make out? I'm looking forward to connecting yours & mine together and letting them get acquainted ;-)
Click to expand...

Yes! I was able to get back to it today, and I pulled out my 25 pin RS-232 breakout box along with all my adapters to go from 9 pin D on the PC laptop to 25 pin D, then to the breakout box, then 25 pin D to 9 pin D, and over to the HP 110+. I Googled the wiring of 9 pin D connector to 25 pin D connector, just to be sure. I hitched up only the 3 necessary wires. I buzzed out everything a dozen times to be certain that I was connecting pin 7 on the 9 pin D connector on the back of the HP (gnd) to pin 5 on the 9 pin connector on the back of the PC laptop.

And... YES!!! I have the Term program on the HP 110+ talking to the Hyper-Terminal on the laptop PC. Cabling was the issue, NOT a blown chip inside the HP 110+. Thank goodness!

Thanks to you folks, once again, for all your attention, support and advice. I am so happy that I don't have to face attempting to remove and replace a chip inside this system.

Now I need to acquire a battery, so I don't lose everything I load into the system if it comes unplugged.

smp
 
smp said:
Now I need to acquire a battery, so I don't lose everything I load into the system if it comes unplugged.
Click to expand...

Last night I ordered this battery:

http://www.apexbattery.com/panasoni...-lead-acid-batteries-panasonic-batteries.html

$9.50 plus $5.88 for shipping. That was the best price I found anywhere.

When it arrives, I will have to make a couple of jumpers from the battery terminals to the screw terminals on the computer board that are available there in the battery compartment. I don't think that will be too much of a big deal.

smp
 
Price sounds reasonable. Not sure what screw terminals you mean? There's a little board that gets glued to the side of the battery that has leads to go to the battery terminals and two threaded terminals that connect with the straps coming out of the computer; is that what you mean? You can see it in my picture in post #5.

In any case, should be no sweat to connect the battery somehow.
 
MikeS said:
Not sure what screw terminals you mean? There's a little board that gets glued to the side of the battery that has leads to go to the battery terminals and two threaded terminals that connect with the straps coming out of the computer; is that what you mean? You can see it in my picture in post #5.
Click to expand...

Yeah, I do not have the board to glue onto the battery because I got no battery with the computer. I also have no straps coming up off the computer, only the two screws that used to fasten the straps onto the computer. Your picture shows those two screws. One has a big plus sign printed next to it. I intend to make jumpers from the two terminals on the battery to those two screws on the computer.

smp
 
Ah, THOSE terminals :blush: Duh, had to open it up to look; forgot what it looked like in there... ;-)

Yeah, should be no sweat at all. Enjoy!
 
Hello all, I'm back with my HP Portable Plus again.

This afternoon I spent some time with this system. I attached my battery with a couple of jumper wires, and it seems to be charging up nicely with the AC adapter attached. With no battery and only the AC adapter, the system always reports the battery is at 80%. With the battery attached along with the AC adapter, the battery indication started out as 80% and has steadily risen to over 90% and is still rising. I am very hopeful that I will be able to use the battery and not always have to be tethered with the AC adapter.

So now I get to the point that I always get to with my vintage systems: How do I get software into this machine?

This system comes with MS DOS 2.1, and also has EDLIN for text editing and TERM as a simple terminal program. I also have a program called Reflection installed in my ROM Drawer. I figured that between these two terminal programs, I might be able to transfer .EXE files from another laptop PC into the HP Portable Plus.

I now have determined that the built-in TERM program is only capable of transferring ASCII files back and forth with my laptop PC running Hyper-Terminal.

So, I then turned to the Reflection program. I dug up the user manual and... I found that it only knows how to interface with two different special transfer programs - one that works on VAX systems, and the other works on HP 3000 systems. Of course, I have neither of those two systems...

So, once again, I have a great working system, and I am currently at a loss for how I might transfer application software into it. Anyone have any suggestions?

Thanks, in advance, for any suggestions or advice you may have for me.

smp
 
If the program is less than 64KB, you can encode it into Intel hex format. On the 110, you can then use DEBUG (which understands Intel hex files) to create a straight binary image. Hopefully, that will allow you to get a standard transfer program into the machine, say, XMODEM.

Just a thought. Does the 110 floppy drive work okay? If it does, there is a device driver that can be installed on an MS-DOS machine to format and write 110-compatible floppies. It's called HP110.SYS.
 
If you have DEBUG on 2.1 you could use the terminal software to transfer a .HEX file and then use DEBUG to .COM/.EXE it for you.

... I think. Never have done it with DOS... only CP/M... :D

Yup... see Chuck beat me to it! :D
 
Tingo, Chuck & Lee, thanks a million for the ideas. I'll put in some more time on this tomorrow, and report back with what progress I make.

Chuck(G) said:
Just a thought. Does the 110 floppy drive work okay? If it does, there is a device driver that can be installed on an MS-DOS machine to format and write 110-compatible floppies. It's called HP110.SYS.
Click to expand...

I have no floppy disks with this system, only the internal solid-state disk the system makes out of internal RAM.

smp
 
Hi all, I'm back again.

Yes, I have the CTTY command in the HP 110+. I have been able to type CTTY COM1, and then my laptop PC with Hyper-Terminal running becomes the console for the HP 110+. It's pretty cool, actually. I've never tried that before.

I found that I do not have the MODE command, probably because the HP-110+ has the ability to configure all of its I/O ports built into the PAM monitor program that is the default user interface when the system is turned on.

I have installed DOSBOX on my laptop PC, and I can run Laplink 3, but even though I followed all the directions in the link provided by Tingo, I have not been successful in getting LL3 to transfer itself over to the HP-110+. I keep getting an error message indicating the COM1 port is not set correctly. Since I do not know anything about how Laplink works, I am somewhat at a loss.

I saw the note on the link provided by Tingo that this all is supposed to work ONLY with a Laplink cable, and I have purchased one online. I will have to create some sort of adapter to change from the 9 pin D-type connector on the HP-110+ to the 9 pin D-type connector normally found on the back of PCs in order to use the Laplink cable.

Then, I also saw that this is only supposed to work with the 6 head LL3 cable, and, of course, I have a 4 head LL cable coming to me. Sigh!

What I am trying to accomplish is a way to get GW BASIC into the HP-110+. Folks mentioned that since I can transfer ASCII files, I should be able to transfer an Intel HEX file. Does anyone know how I would go about changing the GWBASIC.EXE file that I have into an Intel HEX file?

Thanks very much for listening. Any ideas or comments are very welcome.

smp
 
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