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Netronics Explorer/85

falter

falter

Veteran Member
Joined
Jan 22, 2011
Messages
6,580
Location
Vancouver, BC
My Explorer/85 board arrived today.

20160908_165950.jpg

20160908_170024.jpg

Looks to be in decentish shape. I was hoping for the variant or 'level' that had the case, PSU and keyboard, but, these are exceedingly rare (this is the first one that has come up I think in 2 years plus), so I'll take what I can get. Netronics stuff seems to be hotly contested these days on ebay so it was nice to get it for just over a couple hundred dollars.

I suspect this was together with that keypad we saw. The same seller also sold an expansion board that increases the number of S100 slots to 6. But for some reason some knuckleheads fought over it and it was at almost $130USD which I thought a bit much for what it is. Do kind of wish I'd grabbed the keypad, but I'm hoping the serial terminal function exists and works on this.

I *think* that 25 hole area shaped like a DB25 is probably the serial connection. I'm really not sure how this thing was interfaced before, probably just by hex keypad. Key will be figuring out what level it is and then working backwards from there. The board is a Rev C. I notice they didn't solder in a reset button, so I'm assuming that must have been done via keypad.

I don't unfortunately have any power supplies that crank out 8V.. so probably time to invest in a good bench supply so I can roll with these things.

I've put higher res pics here for those curious:

https://drive.google.com/folderview?id=0B4pq0-BHd2x6bjY3MTRZbGRCQmM&usp=sharing
 
Yeah, that's a Vector S-100 protoboard. Probably some parallel I/O interface to an experiment or project.
 
Hi Falter,
Did you get some manuals or documentaion for it? I have bought one from a guy here in Surrey, BC (looks like it was made from scratch--Netronics kit?). It is comprised of a big board like yours, an ASCII keyboard and some manuals or documentaion. Was lucky to get it for $40Cdn but that is about 3 yrs ago. Unfortunately, I have not touched it since I got it.
I may have to dig it from storage and see what else came with it. I believe this was lower level as per Wiki.

RT

BTW...THE MANUALS can be downloaded from here (maybe you already know����)
http://www.hartetechnologies.com/manuals/Netronics/
 
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I'm trying to get a couple of dead S-100 systems up in running after having them in storage for years (decades?) and recently dug out my Netronics Jaws 64K Ram board I bought for use with my Quest Super Elf single board computer (also dug out) back in the early days. I also have a Netronics video terminal board that needs some TLC to get up and running again. A couple more projects to try to make work.
 
I've figured via the manual out that mine was in fact configured for hex keypad use.. so that is at least known and that is what that keypad was for. Still kicking myself for missing the psu but whatever.

The manual is a bit circumspect on how to wire up for serial terminal. There are holes on the board arranged in a pattern that look suspiciously like a DB25 but for some reason I can't find a pinout for it.

I wish I'd grabbed the expander. And although it is unlikely I hope a case appears some day.
 
Took me years to get a case - wound up buying a whole "new" EX-85. Did you fined a Power supply yet? I may have an extra one if I can locate it.
Do you have a way to read the monitor chip love to get a copy of the keypad monitor. I have the files for the Keyboard monitor and the MS basic as well. My programmer can program 8755s if you need on made.

FYI my first EX-85 was a kit purchased new in 1979 (also my first computer) The monitor is heavily based on the SDK-85 so you might want to look at documentation as well.
 
Forgot to mention looking at the pics of the board, if you haven't figured it out yet the 24 pin socket net to the monitor is the keypad interface, I believe that version did not support a serial console.
 
I was reading through the manual a while back.. IIRC my board is version C. In the manual they describe jumpers you can set to use a serial interface. But yeah.. I don't recall where one hooked it up.
 
Physically it will support serial interface but I think the hex monitor does not have a serial console routine. You would have to load a program for that. Can you burn 8755s? If so you can replace the hex monitor. I would like a copy of the hex monitor if possible. If you can't I think I have an extra 8755 I could burn the serial console monitor in to.

The board uses the SID and SOD pins for serial in and out and for the cassette tape in and out. J1-3 is the output and J1-2 is input J1-1, 7, and 19 are all grounds.
 
I still have my old Explorer/85 and documentation if anyone needs more information. You are correct the the DB25 is for the serial port, but there were two different versions of the ROM monitor that supported either keypad or terminal. IIRC, there were also some jumpers that had to be installed differently.

I'm currently building a functional clone of my old Explorer/85 using more modern components, like a single 32K EEPROM and 32K RAM. It's actually running Microsoft Basic/80 on a horrible rat's nest of wires on a solderless breadboard.
 
Thanks nib!

I seem to recall reading in one of the online copies of the docs that the 'ikbd' chip was the ROM monitor? Is that correct? For some reason I can't find it now.
 
I agree there were two versions - one for the terminal using the serial port and one for a hex keypad that if I understand the documentation did not support the serial terminal. Interested in hearing more about your project - are you going to incorporate the s-100 as well? Is it a serial terminal version or the keypad version? Been looking for the contents of the keypad version - would like to convert one of mine.

I have 3 EX-85s the one I am looking at has an 8355 with EXPL85 on it. My original has an 8755 that was a replacement from Netronics - a log time ago when it was my primary(Only) computer probably 1979 or 80.

Jim
 
The 'ikbd' doesn't sound familiar. The ROM monitor is contained in the 8355 chip. My monitor listing document is titled "Terminal Version" and there is no code in it to support the keyboard.
 
Jim - Definitely no S-100 or anything that ambitious. I was a poor high school kid when I build mine originally, so I'm just trying for something that will run Basic and the Monitor like the original. My new board is a simple 8085 with a single 32K RAM and a 32K EEPROM. The trickiest part was the power-on jump circuit that allows the RAM to be in the lower half of the address space. I'm trying to pull all of the project notes together to put the pieces on github. Along with the hardware, there's an Arduino-based programmer for the flash and a cross-assembler that is compatible with the format of the original Monitor source code.

I've never run across the Monitor ROM for the keypad version. They were marketing this as a larger system and I suspect that they didn't sell a lot of the keypad variant.
 
I got everything I needed by booting the old board and capturing monitor dumps to a terminal. The computer portion itself isn't very novel, but a few interesting tools came out of the project. I'll start a new thread when I get all the documentation together so I don't hijack this one any further!
 
falter,

I just took another look at your photos and realize what you meant by ikbd. You are correct - that is the ROM monitor burned into an 8755. Mine is in the factory-programmed 8355 instead. I'll post a pic so we can compare boards. Yours has the connector for the keypad next to the 8755, so it looks like you do have the elusive keypad ROM. I'd be interested in seeing the differences between that one and the terminal version. I have the printed ROM source listing and have disassembled and reassembled mine to relocate a few things, so I'm familiar with the code.

In this pic, one side of the serial port is going to and actual PC serial port. The other side had a blown transistor, so an FTTI chip (and an inverter) are connected directly to the TTL output. It put one side of the conversation in one terminal window and one half in another. Awkward, but it worked well enough to dump the contents of the ROMs.
Exp85.jpg
 
Do you have the actual manual for the monitor. I too spent time dissembling the ROM but I now have the manual. I too am interested in the keypad ROM. I did discover a lot came straight from the SDK-85 monitor so I suspect the Keypad ROM does too. Are those the Basic ROMs in your board curious as to what is on the labels?

Link to Monitor listing and Basic user manual.

https://dl.dropboxusercontent.com/u/8496003/Netronics EX-85 manuals.zip
 
Those are the Basic ROMs. Two new photos are attached that show things a little clearer.

Thanks for the link. I have those same manuals, same versions, although not scanned in. I should probably have the Basic manual under glass. It was probably stapled by Bill Gates himself.

I originally tried to scan the Monitor source to OCR it, but the columns and the line wrapping were a mess. In the end, I scanned the last few pages of symbol table and OCRed them without too much trouble. Then used that and the binary as input the the most excellent dasmx and got a more-or-less exact copy of the source minus the comments. I've gone through and commented at least the breaks between the routines, so now I have a pretty good version of the Monitor source to work with.

I've looked around for the SDK-85 monitor, but haven't found anything other than user manuals. At this point I suppose it doesn't matter much because I have good source to work with.
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