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+--- Thread: I found an old 'bee! (/thread-654.html)
I found an old 'bee! - Rocka - 08-06-2023
Hi Everyone,
I hope someone may be able to help or refer me to someone who can please.
I just discovered a Microbee in my garage (missing the power adaptor and cable), that I saved from landfill during a shed clean out at my work some 20 years ago. (I worked at a local phone system company).
An ‘Ericsson’ sticker on the bottom of the case indicates an installation date of Nov 88 and that a battery was last changed in 1993. Having the Ericsson sticker on it, I’m wondering if it may have been used as part of a telephone system. (Possibly collecting, storing and printing out time stamped telephone call records.) There is no longer any battery connected to the upper cct board and the PCB track is lifting at that location!
I once owned a Bee so I have a soft spot for the Microbee. I’d like to restore it to working condition and find out ‘what’s on it’ or re-purpose it. I don’t recall my original Bee having a vented top case and I’ve never seen another one with a red LED mounted to the top cover near the BS key.
I’ve noticed a sticker under the top cover that says “Last Service 21-1-91” so Ewan may have serviced this computer!
I’ve discovered an additional board jammed underneath the main board which contains 5 ICs, a Programmable Peripheral Interface, a Real Time Clock, a dual flip flop, a hex buffer, a 555 and numerous connecting wires into the Microbees own boards. There's a separate piezo buzzer and a rear mounted push switch. There’s also a daughter board attached underneath the main board and the said LED.
After long hours searching, I located the pin functions for the 5 pin din socket, (although still managed to get it reversed first try).
So connect it up to a ‘power supply’ and ‘TV video in’ is what I did.
Almost immediately 2 asterisks and a flashing underscore appeared on the screen. But that’s it! No illumination of LED, no response from any key except reset which seems to reset the computer if held for 5 seconds or so. After leaving the computer sitting there for about 8 minutes with the cursor flashing, all of a sudden I was startled by the piezo buzzer buzzing continuously!
At the back there is the 25 pin serial, 15 pin I/O and the unlabelled 9 pin socket.
Any assistance would be greatly appreciated identifying what exactly I’ve got here, what its set up to do and whether it can be restored or re-programmed to be something slightly useful.
Regards, ‘Rocka’.
RE: I found an old 'bee! - ChickenMan - 09-06-2023
Welcome to the forum, I'm sure the experts will be able to help you out.
Yes looks like something Ericson used for what ever. Are you able to dump all the ROMs as they may be able to tell what its been used for. The coreboard is a late model PC85 coreboard and the baseboard is a Premium version, as the 9 pin at the back is colour CGA out. So it ultimately could be turned into a Premium PC85 with a new set of ROMs.
RE: I found an old 'bee! - someone - 09-06-2023
Welcome aboard!
A few wiggles of the coreboard connectors is often enough to coax a microbee working again.
Also, it is usual that the keyboard contacts have died and require retreads or replacement.
To find out more, someone would love to have a closer inspection of the unit.
As a guess from the photos it's an OKI MSM5823 RTC connected via the 8255 PPI.
Interestingly enough the same was done with a prototype Microbee Floppy Disk Controller that didn't make it to market;
it too had an RTC connected via a 8255 PPI, a baud rate generator and a dual port UART for "Real" RS-232 Ports.
The piggyback board looks like an expansion of the CHAR, ATTR and COLOUR RAM to accomplish more video functionality from different screen configurations.
Have a look at the Doppelganger posts to see what's possible from the Games front.
RE: I found an old 'bee! - Ernest - 11-06-2023
Welcome Rocka,
Looking at the Coreboard, the ROMs are in locations.
Two left are in the BASIC Rom positions.
Then Pak ROM 0 is empty as is Pak ROM locations 2,3 & 4.
The next across is the NET Rom or TELCOM location.
Then Pak ROM Location 1 & 5 are both populated.
Depending on what other hardware mods have been done it may not be too difficult to return to a Premium PC85 configuration.
Interesting that it looks like the LV5 mod to bank switch the ROM A (BASIC) between an lower and upper bank is fitted, however the ROM is only an 8KB ROM not a 16KB so no upper bank to switch to.
ERNEST
RE: I found an old 'bee! - CheshireNoir - 11-06-2023
Also an option is to get a Floppy Disk (DRAM) core board and swap out the ROM (SRAM) board. That'll give you a Premium with at least 56K of RAM. More likely 128K.
There are changes that need to be made to the main board to prep it for being a Floppy (DRAM) board, but it's well documented in the Microbee Hardware Notebook with Updates (In the repository. It's probably the most useful document out there for Microbee repairs)
If you do stick with the PC85 configuration, I've done up a ROM swapper board that sits in the ROM I position that gives you 16 different ROM images that can be switched out for each other. (See here: https://github.com/cheshirenoir/BeeMultiRom)
If you do go down that path, I probably have spare PCBs somewhere.
John
RE: I found an old 'bee! - MbeeTech - 13-06-2023
Ericsson did use Microbees (which they added bits to) for front of house Motel phone system integration.
The Microbee patched into the pabx and collected phone usage data for billing to the rooms.
I did service one of them at a motel in Wangaratta at some point, but if I recall correctly, it was a standard (non-premium) bee
with a larger add-on board underneath. The machine was working, but, as usual, key switches were problematic.
It was only by chance that I repaired the machine as I was doing the rounds of the schools in the area at the time and chose
to stay at that motel only to find a bee behind the desk.
RE: I found an old 'bee! - someone - 15-06-2023
Hi Rocka,
Are you able to get a ROM DUMP to Chickenman so they can be archived?
RE: I found an old 'bee! - Rocka - 21-06-2023
Hello,
I don't currently have an EPROM reader/writer, but would be most grateful if another member could help (Please private message/email me). After dumping I'd like to erase and burn something useful onto them in the hope of restoring the Microbee to proper working condition. I don't really know if it is functioning properly anyway.
Lately I've been sidetracked by resurrecting my TEC 1A (Talking Electronics single board computer) and connecting up add on boards!
Rocka
RE: I found an old 'bee! - ChickenMan - 22-06-2023
I can dump the ROMs for you no probs there, will PM you.
Great to see your TEC-1 running as well, we have a heap of files re the TEC-1 in the repository, so check 'em out.