Archive for March, 2012

A2 proto board update

Friday, March 30th, 2012

After an email exchange with Vince Briel where Vince casually indicated that the A2 community really needs a prototyping board, I’ve decided to raise priority and get a batch of these prototype cards built.

I’m a little concerned about timing, especially with the 6522. The Mockingbird board, which also uses the 6522, does some strange stuff with clock timing and I need to really investigate what is going on with a real board. So, before doing the production build, I need to get a prototype proto board working.

Normally, I would just etch a prototype PCB at home, but a proto card needs a bunch of holes drilled in it which would take a long time to do manually and besides, I might need to make some significant changes, which is easy to do with wirewrap. In addition I had on hand an Apple Hobbyboard, which is ideal for this project. The Hobbyboard had been used before for a simple temperature sensor project that I did in the 80’s, but the old circuit had been removed from the board a few years ago. So in the last week, I have wirewrapped the new circuit onto the old Hobbyboard.

prototype proto board

prototype proto board

I haven’t gone very far in debugging because I keep frying the 16V8 GAL chips I’m using to cut down on chip count (and leave more prototyping space). Could be something to do with the ancient Data I/O Pal programmer I”m using. Anyway, there is real progress being made on this project and I hope to get things squared away so I can make a build this spring or summer.

Bare Mimeo PCBs now available

Tuesday, March 27th, 2012

Price is same as before ($150).

Follow this link for more information.

Kits will be available this summer.

VCF EAST – May 5th and 6th – Wall, New Jersey

Friday, March 16th, 2012

There are going to be some great speakers this year. Make an effort to join the festivities – it’s a great time.

VCF EAST 2012 flyer

New Foam For Imagewriter

Saturday, March 10th, 2012

During the clean up of the mechanism of the Imagewriter, I found that the old foam which was attached to the enclosure was disintegrating. I’m sure that the foam was placed there to help reduce the sound, as the machine is quite loud. It was so far gone, that it was making a mess of everything. I had to replace this foam, because putting the cover back on the chassis with all it’s bad foam, would have created a new mess in no time. While testing the printer and waiting for replacement foam, I left the cover off and shorted the switch that normally disabled the printer when the cover was removed.

All the foam pieces were installed on the cover of the printer, except for one piece that was installed in the bowels of the chassis. That piece was still in relatively good shape. There was another circular piece on the cover that went around the carriage which was also in good shape. I left these two pieces of original foam alone.

The replacement process worked like this. I measured the thickness of the foam and found that all pieces were 1/4″ thick. Since I couldn’t find anything likely to work during a visit to Home Depot, I went online and ordered a couple of different weights of Volara 1/4″ foam from Foam Factory’s online site. One reason I chose the Volara foam, is that it was described as being good for acoustical purposes. The stuff I ended up using, was the heavier 4 pound density. This wasn’t an exact match, but I would call it a fairly close match to the original foam.

Once I got the new foam delivered, I went to work removing the old foam. I soaked the old foam in Goo Gone and carefully scraped it off with a small paint scraper. I was a little worried about the Goo Gone stripping the paint or melting the plastic of the printer, but this did not happen. Removing the foam took at least an hour. After cleaning the cover with soap and water, I went to work putting the new foam on. I cut the new foam with a paper cutter so it would have straight edges and glued it by spraying with Scotch general purpose 45 spray adhesive. The reason why I chose this adhesive is that the can indicated that it was good for foam. It was also cheap! The glue works a little like contact cement in that it is best to let it set up a bit before applying the foam.

This is the result of my foam job. Note that the magnetic switch seen on the right side of this picture was removed from the cover while I did the work.

New Foam For Imagewriter

New Foam For Imagewriter

Datanetics Keyboard PCB Rerun Possible

Friday, March 9th, 2012

If 6 people make firm commitments to buying a Datanetics keyboard PCB, I would be willing to make a rerun. Cost would the be the same as before – $79, but would not include brackets or anything other than the PCB. Drop me an email if you are interested.

Reproduction Datanetics Keyboard

Reproduction Datanetics Keyboard