Microbee CIAB in Tasmania

[vk7hch]

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

[CheshireNoir]

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

[ChickenMan]

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.

[vk7hch]

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.

[CheshireNoir]

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

[someone]

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.

[vk7hch]

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!

[ChickenMan]

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.