Netronics Explorer Help

[mykrowyre]

I found this Explorer 85 at a yard sale... nobody knew what it was. I had some idea when I saw the floppy drives, and a google search came up with 8085 computer.

I couldn't pass it up, but the computer was missing the CPU and several other IC's. There is some very terrible work in there. I believe it came from a a technical school's electronics repair class.

To me, the board looks unfinished. Looks like the ram was never installed?

The blue cover (not pictured) does not have the key lock on the right. It's attached with only 2 screws in the back and tabs in the front.

I'd like to repair (or finish) it.. I did find the manuals and rom images online.

There is an internal power supply, with a fan, which I have not seen mentioned anywhere, but I did see it in the manual I downloaded online.

I also acquired two 8" floppy drives (CDC-1), but no floppy controller board which I assume goes into the S100 slot.

Any additional information would be great.

Considering nearly all the IC's are missing, it will probably be a complete rebuild.

Thanks

 

[DeltaDon]

Nice find! Should be an easy rebuild if you have the assembly instructions and none of the chips are all that "rare". I don't have an 8085 from them, but have their terminal board and Jaws 64K ram board for 1802 S-100 usage and I think the pwr supply would be +5, +/- 12 and maybe -5v outputs. Unless also supplied power for the floppy drives. Unless just unregulated and on-board reg's where used for regulating. The Quest Super Elf had option of on-board reg's or external regulated power supply.

 

[mykrowyre]

I went thru the the assembly instructions and verified that all chips and components were installed correctly. Checked power supply and the 8V sides are good but the 20V output only reads 6V. The power supply doesn't match the schematic at all so I'm not sure what's going on there.

Nothing I have requires 18V yet (I don't have any S100 cards) so I'm going to leave it disconnected for now.

The missing chips arrived (ebay), and I burned the monitor to eprom.

Flipped a coin trying to decide to pull all logic chips (some were soldered in) to test for 5V VCC or if I should just go for it and hope for the best.

Regulators are on the board so the only way to test is to power it up.

Decided if it was going to fry the chips it would have already done so, and that would likely be why half the chips were missing in the first place.

So.. I powered it up without 8085, 8155, and 8755, and found a good 5V VCC. Yay.

Tomorrow I'll wire up the serial port, install the 8085 and supporting chips and hopefully will get the some response from the monitor.

I'm doubtful because the board has been hacked up pretty good with poor soldering but maybe I'll get lucky.