Archive for November, 2010

Datanetics PCB update

Tuesday, November 30th, 2010

I’ve had a pretty small response to the offer on the Datanetics PCB.  Despite the small numbers of folks interested, I’m still going ahead with this as a one time deal.  Before doing so, I’m going to spend the next couple of days looking for better pricing on the PCB.  Ordinarily I’d stick with my current fab house, since since I have had such good luck with them.  However this PCB doesn’t have a solder mask or silkscreen, so I should be able to find a cheaper place to do this board and still get good results.   Since I haven’t collected money yet – if I turn up a better price, I’ll adjust the pricing.

The ACI Parser Bug

Tuesday, November 16th, 2010

I don’t know if this is really a bug or a compromise in the design needed to get it into 256 bytes of code space.

Always enter all four characters of 16 bit hex address when entering addresses into the ACI parser.  The parser doesn’t clear out preexisting addresses, so unless you enter all four address characters, you will use whatever was already present in memory mixed in with the new address.

EXAMPLE:  to load Hamarabi enter the following

004A.00FFR 0400.0FFFR

Datanetics Keyboard Plans

Monday, November 8th, 2010

These PCB boards are turning out to be very expensive to make, partly because of the need for the array of unplated vias in the encoding matrix on the upper left side of the board.  These unplated holes push this project into a custom fab process pricing, which increases cost by 25%.  Because of this, and the specialty nature of this project,  I’m not sure how many to order.  What I’ve decided to do, is to make November a pre-order month.  At the end of November, I will order enough to fill the pre-orders only.  There are no plans to stock or inventory any of these PCBs to sell later on.  The cost of the PCB will be $79 and will include no hardware, chips or other components.  I can’t even guarantee the PCB will be error free.  Actually I’m reproducing a design error that was on the original, but beyond that I can only say that I’ll do the best that I can.  However, if they turn out to be unusable, I’ll eat the cost and either get a new batch made or refund your money.  Shipping within the lower 48 US states will be free. Add $25 for overseas shipping.

Pre-orders will the accepted through the end of November.  Fabrication of the PCBs is expected to take a month, and shipment to you about a week after that.  Which would put the PCB in your hands in the first half of Janurary.

send email to “” for preordering information.

PS. If one of us can find a sheet metal vendor to do the stiffeners, I’ll be glad to coordinate a batch purchase of those at cost.

Small Apple Cassette Interface update

Monday, November 8th, 2010

I have had it confirmed from an independent source that the ACI works fine with Vince Briel’s replica 1 SE.  This same person has also successfully tried a  Radio Shack 14-109 (no longer sold) as well as the CTR-80A which is a cassette recorder packaged with the TRS80s.

If you have used a particular cassette recorder, successfully or not, let me know and I’ll share the information.

We have both noticed erratic operation of the LED, but I have previously reported that the LED can not be reliably used for setting playback volume.