This is an old revision of the document!
BSB DMAC receivers and modifications
Feature set comparison
Receiver | DataVision (data port) | AGB Audience Survey | D2MAC mod? | Notes |
---|---|---|---|---|
Ferguson SRB1 | ✅ | ❌ | ✅ | Modified for D2MAC and PAL reception by Trac Satellite and others. |
Tatung TRX2801 (Decca DRX-2851) | ❌ | ✅ | ❌ | Data port is present but used for AGB Audience Survey. DataVision not expected to be implemented. |
Philips STU902 | ❌ | ❌ | ❌ | Manual suggests that the data port “may be used for features such as an Audience Survey” |
ITT-Nokia/Salora 5903 |
DataVision support is speculative - it's not known whether this was actually deployed by BSB. An article in New Scientist from January 1990 (BSB faces setback over business data service) says that Ferguson “had been burning midnight oil to write the software needed to decode Datavision, and [believed] it was ahead of its three competitors, Philips, Salora and Tatung.”
A BSB Datavision promo video is available on Youtube.
Ferguson SRB1
Ferguson documentation:
- SRB1 service manual – cleaned up, with schematic pages stitched
- Original Ferguson SRB1 ROM – version FerR2.0e
The SRB1 was the 'standard' BSB receiver at launch, and proved to be very versatile. After BSB's closure, many of these were sold at a low price as liquidated stock and modified to receive other satellite signals. Trac Satellite were a key player in this market, producing several modification kits ranging from a simple D2MAC FTA ROM-swap to a full dual-mode PAL/D2MAC conversion with a Eurocrypt smartcard slot and built-in “two-chip” Multimac smartcard.
Trac Satellite upgrade information
- Trac Satellite D2MAC Upgrade ROM – version 2.11. Convert an SRB1 for FTA D2MAC.
- Trac Satellite D2MAC/PAL v3.00 ROM – dumped from my SRB1 with PAL/D2MAC upgrade.
- Trac Satellite D2MAC/PAL "Receiver" v3.21 ROM (from Trac's old website)
- Works with the PAL/D2MAC upgrade.
- Adds a “Brightness” option to the D2MAC video tuning screen.
- Trac Satellite D2MAC "Internal Card Slot" v3.50 ROM (from Trac's old website)
- Doesn't seem to allow access to the tuning menus. Only has a “Decoder Menu”.
- This was probably used with the Trac “D2MAC decoder” mod, which allowed an SRB1 to be connected to the baseband output of another receiver.
- The Trac “front card slot” upgrade ROM ZIP file was the same as the “Internal card slot” ZIP file, but only contained the 8031 ROM image.
I don't know what the difference between the various Trac Satellite ROMs is, or how to identify the modifications. If you know, please drop me an email: philpem@gmail.com.
“s-band” uploaded the manual for the D2MAC Mod EPROM to Satellites.co.uk: https://www.satellites.co.uk/forums/threads/trac-satellite-d2mac-mod-instructions.178510/
Temporarily reverting the PAL/DMAC mod
The PAL/DMAC modification can be partially reverted to allow the original Ferguson firmware to be used. This can be useful to read out the ACM data on a modified Ferguson receiver.
This is a somewhat involved process and not for the faint of heart.
- Unplug the MAC board from the card reader board. Plug the MAC board directly into the receiver motherboard.
- Desolder the left and right audio wires going from the MAC board to the PAL board.
- Disconnect “VBC” and “VI” from the PAL board. Connect them together.
- On the underside of the PCB, a diode and a wire are connected to the centre pin of transistor TV19. Desolder the diode and insulate the end of the wire.
- Follow the service manual guide to set up VCO levels and RGB cutoff.
Beware that the insulation on the wire used by Trac has a tendency of melting easily. You may need to repair wires with splices and/or heatshrink to reinstall the mod.
LNB types
The Trac ROMs support three types of LNB:
Type | LO offset | Frequency range |
---|---|---|
FSS | 10.0 GHz | 10.9 to 11.7 GHz |
BSB DBS | 10.75 GHz | 11.7 to 12.5 GHz |
Telecom | 11.0 GHz | 11.95 to 12.75 GHz |
The above assumes a receiver tuner range of 0.95 to 1.75 GHz.
DATA port enhancements
The Trac D2MAC/PAL modification adds a 0V/12V switchable output and a PAL video signal to the DATA port.
The DATA port is an 8-pin DIN socket.
DATA port pin | Function |
---|---|
1 | Ferguson: Data output Trac: “VO”: +12V / 0V switchable – NOTE outputs -11V in “0V” mode |
2 | Ground |
3 | Ferguson: NC Trac: Always-on PAL video to decoder. 1V p-p on approx. 3V DC level |
4 | |
5 | Ferguson: NC Trac: “DI”: Decoder video input |
6 | |
7 | |
8 |
The video pins can be connected to a SVA-1 Videocrypt decoder's Decoder SCART port. The de-emphasis filter needs to be enabled if HackTV is being run with the “--filter
” option.
RGB/LO tuning
Press Menu to open the on-screen setup menu. Hold Shift and press 9 on the remote.
- Press Enter to switch to Decoder mode
- Press Cancel to switch to Receiver mode
- 1/4, 2/5, 3/6 adjust the RGB cutoffs.
- 8/9 adjusts the local oscillator
- 0 stores the new settings, VIEW exits without saving
Tatung TRX-2801
Tatung documentation:
Philips STU902
- Philips STU902 service manual (thanks to freeservicemanuals.info)
- Philips STU902 firmware ROM version PhiR211