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View Full Version : Epson HX-20, $10 at the flea market



NathanAllan
November 26th, 2006, 02:14 PM
I'm starting to think that the flea market here is not so bad. Two vintage computers in a month for $10 each is not bad at all.

This one is an Epson HX-20 with no pwer supply, but it looks totally new except where I used my key to make sure it has all of it's roms(it does) and that's not bad either. I have a universal charger that has lots of switchable settings, and I have set it to it's correct polarity, voltage, etc. I just switched it on for a second and its menu came up, so it's alive! Now I get to wait and see what peripherals show themselves.

Nathan

GraceUGrad2006
November 27th, 2006, 05:44 AM
Sounds like you know where to find a bargain.I have been to one flea market in California. It was a good one. I am going to try to travel a little this summer so I am going to hit a few when I am on vacation.
Angel

NathanAllan
November 27th, 2006, 07:47 AM
I have been exploring this machine more, and at first it was giving me trouble. I kept getting garbage data on the lcd and beeping errors. I hit a few buttons and did my best to navigate around its menu and got to the screen where it asked me to set the date. It's definitely NOT Y2K compliant, it went back to making errors when I put in the year as 06. I put it in as 86 and now everything seems to work fine. It has BASIC, SkiWriter, and Monitor(?) in ROM and they al do something. I printed out a few things on the last little bit of paper it has in it with the last little bit of ink it had. I still have to get a tape for it (it hasthe cassette drive) to test that but I suspect it's going to check out good. Funny about this machine, it has two different kinds of serial ports, one rs232c and one that is supposed to be faster, both are DIN sockets, SERIAL has 5 pins and the rs232c has 8. The one marked SERIAL has a faster connection, according to the websites I read (Thanks Terry!) so I was actually thinking of some generic peripherals with homemade drivers for the BASIC that's there. I have the Basic book, might as well use it (if I can find something for using, say, an infrared adapter?). I even found a webpage that tells basically (no pun intended) how to talk to this thing through it's rs232port using LINUX!

One question: If this thing was made by Epson, would my Epson printer (LQ370) be able to communicate with it(no serial on the printer)?

Fascinating machine!

Nathan

GraceUGrad2006
November 27th, 2006, 07:53 AM
Do you have the start disk for your printer?

NathanAllan
November 27th, 2006, 08:53 AM
I have it, but I don't have a disk drive for the HX. That's okay, I'm looking forward to building the cable to null over to the PC to transfer a bunch of files to the cassette onboard the HX. This thing has a following.

GraceUGrad2006
November 27th, 2006, 09:29 AM
Ok I have had to use a either the start up disk or download from internet because the printer I had did not recognize my computer when I got a new one.

Terry Yager
November 27th, 2006, 09:33 AM
You can still buy the printer ribbons at OfficeMax, etc. Epson is still making printers of that design, included in a number of POS terminals. I haven't found a source for the little paper rolls, but it's a standard width, so creating your own mini rolls from a larger one should be a piece of cake.

--T

NathanAllan
December 1st, 2006, 08:53 AM
was there ever a telnet client or terminal program for this thing? I'd like to get it to talk to something else. And from what I have read, there are two empty rom slots on the inside, any idea where roms could be had? I know that's a longshot. It has a basic in it, and I want to try to get it to talk to a modem. I have one that will dial down a lot that I think I can use on all these machines.

Terry Yager
December 1st, 2006, 09:38 AM
Actually, there is only one expansion ROM socket, and yours is already populated with the SkiWriter chip, IIRC. There are other ROMs, but we'll probably never see them.
As for a comms program, the only one I've found is on the Epson FTP page I sent ya, but the gotcha is that (as I discovered the hard way, after laboriously typing-in the BASIC code), it only works if you have the RAM expansion module.

--T

NathanAllan
December 3rd, 2006, 01:07 AM
Hmm. i don't have the expansion and probably will never see one. Are there any telnet or terminal programs around that are written in BASIC? I could probably use one of those. I'm trying to avoid transferring to microcassette, which has proven in the past to be a true PITA. Is there anything I can just retype? or a tutorial to make one? Time to hit the books. I'll see what I can come up with.

Terry Yager
December 3rd, 2006, 08:11 AM
Look in your IBM PC BASIC manual. There should be an example of a minimal comms program, IIRC.

--T

NathanAllan
December 9th, 2006, 12:10 AM
I'm still revisiting the books I have on BASIC for this thing (I don't have that particular manual, but I havea few) and am figuring much out about this thing.

About the batteries, the specs in the pdf file I got fot its manual says that the batteries are four sub-C 1.2v at 1100mah nicd. I have four 1.2v 2650mah nimh AA sized cells. I can easily drop these in with a holder. I'm pretty sure it'll work but I wanted to run this by y'all first. Does the physical size really matter?

I'll have more questions later, just one at a time.

Nathan

Terry Yager
December 9th, 2006, 10:22 AM
I've read somewhere on the net that somebody successfully replaced the battery pack with AA cells, but I haven't tried it myself. You will probably have to experiment with charging times so as to not under- or over-charge them.

--T

NathanAllan
December 15th, 2006, 07:13 AM
After a few recharges (on the original battery) I find I can run it for about 8 hours before I need to recharge, give or take one hour. This is good but the batteries still need replacing, so I am going to proceed. Unfortunately I have to order the battery holder for it, but that's okay.

I got the RealVoice module from Terry (WOOHOO! Thanks!) I told my mother and she got me to leave her a voicemail of Stephen Hawking asking her for her chili recipe :) Seriously, the module makes the computer much more usable. Still doing my homework on it. There's a port on top that is still a mystery to me, but I'll figure it out.

Has anyone ever made any homebrew items for this thing? I'd lke to see what I can do with the cart slot. It's for ROMS that are rarer than the rest of it, so it's homebrew time.

The cassette module for it works great, but only when it's fully charged. Otherwise it gives me an I/O error. Needs batteries. Too easy. Also working on making custom cables for telnetting stuff. Gotta communicate!

Terry Yager
December 15th, 2006, 12:13 PM
I have some kinda light-board thinggy (120x red LEDs), that jacks into the port on the RealVoice. I haven't yet figgered out it's purpose, but I have been able to make the lights blink in different ways by expirementing with the RealVoice menu options. It's some kinda AdaptiveTechnology, and mebbe I'll find some info on it someday.

--T

chuckcmagee
December 17th, 2006, 08:04 AM
I almost purchased a HX-20. Glad I reread this thread first. I thought the PX-8 was a pain. Looks like it's a piece of cake compared to the HX-20. At least the PX-8 comes with a built-in TELECOM program. I did have to make my own serial/rs232c cable using a MAC male-male din cable cut in half for the PX-8. Works like a champ.

chuckcmagee
December 17th, 2006, 08:05 AM
Yes on HX-20 printer ribbons! They are available all over the place! Surprising.

Ok. Ok. The HX-20 had such a low starting bid.... We will see if anyone else is dying to buy one.

NathanAllan
December 17th, 2006, 03:00 PM
I haven't been able to find any telecom roms for this thing. I looked in my pdf manual and there is some way to activate CP/M programs stored in memory from MONITOR. Here's what's on the screen:

A=00 B=00 X=D77E
C=C4 S=04AF P=D23B

I don't see anything like programs and those look like memory locations to me.

I've been looking around and for some reason I can't find any programs that are written in MS Basic 1.0 for using the serial port! Frustrating! Does anyone have a direct link? I found one that tells how to connect it to a Linux box, and I did everything as it said but the cable. It said to make it with full handshaking :(

I tried making a basic null modem cable for it but apparently still have to work on it. I didn't use any handshaking and used only the TXD, RXD and GND lines. It didn't work. Apparently it needs to have the handshaking present. I only did it this way(with three lines) cause that's what hardware I have on-hand. I *never* thought I'd be using those 3-pin DIN plugs for anything and it looks like I was right. When hooked up to the win95 laptop using hyperterm all I got was one character (junk data).

Terry, that blinkenlights add-on sounds like some kind of tester thing, so you can see if the pins are all hooked up (?) My guess. I also got a standard paper roll from work and ONE of those rolls will make TEN for the Epson, so I'll have no shortage of paper!

There's a place right down the street from me that seems to have all the printer ribbons in existence, but I keep missing their hours. I'll get one eventually.

Nathan

Terry Yager
December 17th, 2006, 03:34 PM
The HX-20 does not have any CP/M, in ROM or otherwise. It's a Motorola 68xx-based machine, so CP/M is not even an option. All that's in the main ROM is BASIC and the Monitor program. The display you see when you select the monitor from the menu is just a dump of the (master) CPU's registers:

A = A(ccumulator) (8-bit)
B = B reg (8-bit)
X = (inde)X reg (16-bit (when combined with Y reg))
C = C(ondition Code) reg (8-bit) aka Flags in some micros
S = S(tack Pointer)
P = P(rogram Counter)

The values in the regs can be edited to enter ML code of your own.

--T

chuckcmagee
December 17th, 2006, 03:35 PM
Monitor is about the same as "debug" in MS-DOS land. It lets you do all that "machine language" type stuff, read files into memory, move memory around, clear memory, change registers, save memory to files, alter next "program counter location", etc.



Oooo, look. Terry and I both posting away at the same time.

Terry Yager
December 17th, 2006, 04:04 PM
The light board is made by ACS (Adaptive Communications Systems), just as the RealVoice is. I get the impression that there's s'pozed to be a template or templates that go over the top of the lights and allow the user to select various menu choices using some kinda (magnetic?), (capacitive?) pointer, with the LEDs as visual feedback. The blinkenlights mode is prolly as you said, some kinda diagnostic routine. That's my best guess anyways.

--T

NathanAllan
December 18th, 2006, 01:07 AM
I've decided not to try to make another null modem cable for this thing, but simply adapt the serial port to a standard DB9 and use the storebought null cable. I broke down and spent a whopping $17.24 on parts >gasp!< from mouser. I love those guys. They never try to screw me on shipping and never had any problem with receiving or returning. parts included a snap-in battery holder for the power 'upgrade.'

NathanAllan
January 2nd, 2007, 04:41 AM
Quick update: I got all my parts from Mouser but the AA batteries didn't fit so I just used the dustbuster batteries that I have. So I have a few spare parts for a future project. The batteries are new so they oughtta last a good long while.

I must have done something wrong about the serial cable, cause it didn't work. It was my 2nd attempt and I've been out of practice for a while so I'll try again while I still have parts. Are there any proprietary parts lurking around out there that I can just pick up? Certain part numbers for different cables? maybe some kind of cash register cable?? It has the DIN style connectors like old cash registers, is why I am asking.

NathanAllan
January 9th, 2007, 09:08 PM
Just a follow-up as I work with this computer.

Hints for making a replacement battery cheaply:

Get a cordless drill battery, mine came from a Craftsman. Open it up and you got a lot of sub-C cells, the same cells that the Epson uses. Get four of them out and arrange them the way they're arranged in the Epson. Mine were presoldered all around and all I had to do was disconnect two solder points. Take the wire off your old battery and attach it to the + and - of the drill cells. I crimped mine and it works fine. If the drill cells don't fit perfect, that's okay, you can take out the foam pad on the inside. It'll make a little more room. Mine were still a little tight but that helped to keep the the connection to the batteries tight.

I have charged mine once and I haven't had to recharge yet, and it's been used off and on for six days.

GanjaTron
January 10th, 2007, 07:03 PM
Hi Nathan,

congrats on your find! An HX-20 for $10??? Unbelievable...

I just got an HX-20 off eBay -- for triple the price!
It's actually relabeled Taylor-Hobson, with a sticker covering the original label. Weird.

There's also an additional ROM in the spare socket containing an "RTH Terminal Emulator" which you can call up from the menu. I have no idea how to work the thing, all it does is show a title screen and plays an irritating (and endless!) glissando over the beeper. I assume RTH is the acronym for Rank-Taylor-Hobson, since they were apparently part of the Rank Corp. at some time. Anybody know anything about this? Is it possibly a customised unit for the company?

Btw, mine still had its original NiCd's, and they are *dead*, lasting just 5 minutes or so. I'm a bit apprehensive about replacing them with NiMH since they'd require a much higher charging current than the 200mA the HX-20 uses, otherwise charging times would be unbearable. If I replace the original 1100mAh NiCd's with 2400mAh ones, does it make sense to roughly double the charging time to ca. 16 hours, or is there a nonlinear relationship?

Thanks for any info!

--Roland

Terry Yager
January 10th, 2007, 07:25 PM
I have a charger here that is switchable between NiCad or NiMH, and the only difference is the amount of time before it kicks down to trickle voltage at the same current (400mA for C-cells); 8 hours for NiMH vs 5 hours for NiCad, FWIW.
The replacement Sub-C NiCad cells that I'm using (Eveready No. CH1.2T) have charging info printed on them:

Capacity: 1.2 amp hours
Charge: 14 hours at 120mA max
Fast Charge: 4 hours at 400mA max

The H00AAA charger for the HX-20 outputs 6v. @ 600mA, although the computer can prolly run on a lot less (I'm not sure where you're getting the 200mA from). The recommended charge time is 8 hours with the original charger & batts.

--T

GanjaTron
January 11th, 2007, 06:53 AM
Hi Terry,

the label at the bottom of my HX-20 says:
Rating: DC 4.8V, 400mA
Charge input: DC 6V, 200mA
Charge time: 8 hours

So I assume 200mA is the charging current, since the HX-20 doesn't actually monitor the charge. The manual gripes about using anything other than the original H00AU adaptor, but how's it supposed to differ from any universal adaptor as long as it outputs 6V and at least 200mA?

--Roland

Terry Yager
January 11th, 2007, 10:59 AM
Oh, I see now. I have used the 'wrong' chargers before, with no harm done. The H00AAA charger has the tip reversed from most others, but there is a diode in that part of the circuit to prevent damage if a reversed-polarity charger is used. If you're building your own battery packs tho, be very careful of plugging in the battery backwards, as that part of the circuit has no such protection. I killed an HX-20 once by accidently doing that.

--T

GanjaTron
January 12th, 2007, 06:09 AM
Hi Terry,

I've got those adaptors with reversable tip plugs, so no prob there. I took a closer look at the area around the power connector; as you point out, the + pin of the battery is in series with a diode for protection, and also a fat 2W 3.9 ohm (?) resistor, presumably in case the battery shorts. Incidentally, the diode in mine appears to have been sloppily replaced; looks like someone didn't check the tip polarity. :)

Thanks for the warning about the battery polarity. Fortunately the HX-20 board is clearly marked, which I can't say for some of the others I've seen.

--Roland