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+--- Thread: Microbee CIAB in Tasmania (/thread-755.html)
Microbee CIAB in Tasmania - vk7hch - 30-12-2023
My name is Chris and I once upon a time was a member of the MUG in Adelaide that met in the Unley hall. Wow, that was a few years ago! I had several Microbees then, including a CIAB. As life does, I didn't value what I had then and systems came and went quite quickly. Then you get onto the PC bandwagon and have been there ever since.
I was browsing marketplace a few years ago and saw a CIAB advertised. My wife financed it for me as a birthday present and I put it into storage. Once I find them, I also have (I think I know where they are), the 3 Microbee cookbooks that Tom Moffat released.
Today I unboxed my Microbee CIAB. Still need to replace 3 RIFA capacitors in the PSU due to reputation and make a power/video lead to replace the missing one. But the system has never been used to the best of my knowledge.
It certainly is in pristine condition.
The backstory that I was told was that this unit was purchased, shipped to Antarctica (I think Casey Station), setup there as a spare word processor (hence the printer) but never used.
It was then brought back and sat in storage for many years.
I purchased it from a dealer who bought up the deceased estate.
I have about 20 pictures on the FB group
RE: Microbee CIAB in Tasmania - CheshireNoir - 30-12-2023
Just had a look now. What an awesome system!
Really hoping for you that the keys work OK. Microbee keyboards are a bit of a bugbear, but you can buy replacement kits as they become available from Ewan.
I suspect the RAM will be upgradeable with the addition of 8 x 4164 RAM chips, and possibly a swap of the GAL (If it has the pink GAL rather than the white GAL)
I'm still learning a lot about Microbees myself :-)
Cheers!
John
RE: Microbee CIAB in Tasmania - ChickenMan - 01-01-2024
Welcome to the Forum Chris, if you have any issues with the CIAB or need extra software, just ask. I saw the pics on FB, yes looks like a very clean 'bee, well done. We have a complete set of MUGSA Microbee News newsletters on the Repository that might bring back some old memories.
RE: Microbee CIAB in Tasmania - vk7hch - 05-01-2024
Well there is progress.
I cobbled together a lead, an unused SMPS and the Micron 3 amber monitor that came with the purchase.
First thing I did was bell the lead, it is an audio 5 pin din to 4 rca lead. Pin 1 red, Pin 2 gnd and pin 3 yellow. That is enough to get it going. Convenient colour choice too!
Upon reading other posts regarding not stressing the voltage regulators too much, I turned the SMPS to it's minimum, in this case 10.39v
The big moment arrived.
I removed the covers to take some pictures of the innards.
I still have 4 nonfunctioning keys, I have been given a link to ilike8bits.com dealing with the repair of the keyboard.
I also have a Gotek that I will be adding to the system.
RE: Microbee CIAB in Tasmania - CheshireNoir - 05-01-2024
Great start there!
That "core" board can be upgraded to 128k with a new GAL and 8 more 4164 RAM chips, but I'm not sure there's much software to take advantage of the extra RAM.
Heh. If you haven't put the pieces together, I'm the guy behind I like 8 bits. If you have any questions, I'm happy to answer here or in FB.
Cheers!
John
RE: Microbee CIAB in Tasmania - someone - 05-01-2024
Well done!
Note: When using an SMPS with a bee, it is recommended that the big 4700uF Orange cap is reduced to a smaller electrolytic cap such as 470uF @25V as not to present an overly long transient short circuit to your SMPS upon power up.
It's a good thing to keep the input voltage as low as possible to minimise but not eliminate the risk of tantalum capacitors from exploding or becoming aerial fireballs.
RE: Microbee CIAB in Tasmania - vk7hch - 15-01-2024
The RIFAs are replaced, the PSU appears to be putting out correct voltages (4.92 and 11.87) and the magic smoke stayed where it belonged. I have not had the time to hook it up to the bee yet, I am thinking of putting a buck converter inline to drop the voltage getting to the coreboard.
I just thought of a possibility, remove the bridge rectifier inside the CIAB and replace it with the buck converter. I am probably not the first, but why not!
RE: Microbee CIAB in Tasmania - ChickenMan - 15-01-2024
No smoke, fantastic
My power supplies are either 9.5v or 10v and my Microbee's all run fine with those. 12v tends to blow those aging Tantalum caps near the power regulators.