|Dovetron TBA-1000 Code Translator Manual Serial No. 300 and Up 06 Jun
Scanned by Don Robert House K9TTY
Download 20 MB pdf
|Dovetron TSC-1000 Speed Controller Manual - 0.5MB pdf|
Dovetron Manuals compiled by Vernon G Schroeder K9POU (1929-2006)
p. 01 - MPC-1000CR Regenerative RTTY Terminal Unit
Another copy of these manuals is here
And also see here, here, and here
9/28/14 - Jim Haynes says -
If you have the Binary Bit Processor BBP-100 Mark II as shown on drawing 75349 then inspect the bottom side of the PC board to see if there is an extraneous trace connecting the top ends of R21 and R22. By top ends I mean the ends that are on top if you hold the drawing vertically so it reads right side up. The bottom ends are supposed to be connected together and to pin 6 of U11. The top ends are not supposed to be connected together. If they are the threshold voltage will stay at 0 volts so the threshold correction circuit is inoperative.
Then look at resistors R24 and R25. These are supposed to be 10K resistors. You may find they are 100K, because 1% resistors have an extra digit in the value. If the colors are brown-black-black-orange you have 100K resistors and the unit will hardly work at all after the extraneous PC trace is cut. So replace them with real 10K resistors.
9/29/14 - Jim Haynes says -
The design seems to have gone through many variations. The original design seems to be represented by U.S. Patent 4,013,965 and was all on the main board. The patent goes into great detail about how the anti-multipath circuit is supposed to work. Apparently that didn't work very well, so the parts were pulled off the main board and a new circuit called the Binary Bit Processor was built on a board that plugs into the main board and replaces the original design. This was supposed to be another anti-multipath feature. Mark I of the BBP is shown on drawings 75192A and 75195A. I don't understand that circuit, but then I didn't try very hard since I don't have one. Apparently that wasn't satisfactory either, because there is a Mark II BBP shown on drawing 75349B. There are at least two revisions of that board, having slightly different resistor values. The Mark II seems to have given up on anti-multipath and settled for a simple threshold corrector - or maybe I should say a complicated threshold corrector, but simple in principle.
You can get the patent from www.pat2pdf.org - Other patents issued to Hank Scharfe are 4,229,698 for the LED cross-pattern tuning indicator, 4,243,836 for a digital autostart circuit, and 4,415,964 for a power supply.