This is a modern replica of the Dataman Softy 2 Programmer, the original board was a double sided PCB but without through hole plating, vias having to be hand soldered ! This is a double sided through hole plated board with gold flash for the edge-connectors.
I have made a number of small improvements whilst keeping the layout and tracking as close to the original as possible:
removed all unnecessary vias (connections can now be made to plated through component pads)
tied the floating inputs on IC11 high (pins 2, 3 and 10)
added a video output connector (phono)
added the option of fitting a more available UM1233 modulator as an alternative to the UM1111
added hole in PCB to give access to tuning screw of UM1111
connected 0V between the case pins of the modulator, board will now work without a modulator fitted
added additional links to IC17 (LK1 and 2) to allow fitting of a single rail 2716
added extra positions to IC23 link LK4 to select TMS2716 1K blocks
brought Vpp out to the main edge-connector in addition to the original pad next to the keypad
added pads to edge connectors for headers or wiring
original key-switches are of unknown type so I have changed the footprint to accept one of two more available types - D6 or Omron (as on my MK14 replica)
moved IC23, the EPROM program socket nearer to the edge of the PCB so that its possible to fit a ZIF socket the right way around
added links allowing NENIN (LK5) and NCARD (LK6) to be tied to 0V obviating the need to solder wires to the edge-connector
This board is fitted with Omron switches and UM1111 modulator options.
(It is possible to fit a 6-way Molex type header for the power connections rather than using an edge connector (as shown in the photo), unfortunately the 0V connection is at the bottom of the PCB but a link can be added to make the connection).
A further option for the keypad is to fit a keypad overlay:
It uses 4.3mm high tactile switches and is avaliable from Ian Reynolds: 'Realtime' on the UK Vintage Radio forum or '55theparade' on eBay.
Schematic
The original schematic in the manual has a few omissions, the most significant are that IC12 has no clock and IC6 PA0,1 connections are missing.
It was also quite hard to follow as ICs only had pin numbers and no labels.
Here's what the links do:
| Link | Function | Usage |
| LK1 EPROM Select | selects between 5V (VCC) and -5V (VBB) for pin 21 of the OS EPROM IC17 |
when using a 2708 for IC17 fit both links in the upper* position (towards pin 24) when using a (single rail) 2716 for IC17 fit both links in the lower* position (towards pin 13) |
| LK2 EPROM Select | selects between 0V and +12V (VDD) for pin 19 of the OS EPROM IC17 | |
| LK3 TRANSWIFT Invert | inverts the TRANSWIFT input | |
| LK4 Programmer Socket Select |
for a 2708:
for a TMS2716:
|
when using a 2708 in
the programming socket (IC23) fit the lower link (E to F on the
schematic) when using a TMS2716 in the programming socket (IC23) fit the upper link (E to D on the schematic), select the 1K block by fitting a second link to either the lower left or right positions Note if you wish to READ a single rail 2716 using the adapter (see below) fit the 2708 link |
| LK5 NENIN | when fitted grounds the NENIN signal | fit this link if you are not using the NENIN signal |
| LK6 NCARD | when fitted grounds the NCARD signal | fit this link if you are not using the NCARD signal |
* these positions are referred to with the board on its side with the IC's the 'correct' way around i.e. pin 1 at the top
Bill Of Materials
2716 Adapter
The Programmer socket on the Softy 1 can only be used with three rail EPROMs i.e. 2708 and TMS2716, this makes it difficult to transfer images from other systems. I have made a simple adapter which allows a single rail 2716 EPROM to be fitted, FOR READ ONLY, for the transfer of images.
The link/switch allows selection of either of the two 1K pages of the 2716.
Power Supply
I have developed a power supply for the Softy 1 that provides the four power rails, it is packaged in a neat RS enclosure powered from a standard USB power supply.
The Softy 1 manual states that a 27V programming voltage should be connected to the board. This is a bit strange as the Intel 2708 requires a nominal 26V Vpp (25V min to 27V max), ZD1 and TR4 drop over 3V before it even gets to the 2708 resulting in a very low Vpp ?
This power supply can be configured to either provide a nominal 29V programming voltage by fitting just D1/D2 or if required 26V by fitting IC4. Because the output of IC3 tends to be on the high side of 30V, D1/D2 will put the programming voltage into the right range for a 2708 in a Softy 1.
