BSB DMAC receivers and modifications

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” Modified for D2MAC by Transworld Satellites.
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.

There are several versions of the ITT DMA2285 DMAC/D2MAC decoder.

According to an article in Maplin 'Electronics' magazine, March 1993, widescreen and soft-scramble will only work on chipset version 30 and later.

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 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.
• Manual: "s-band" uploaded the manual for the D2MAC Mod EPROM to Satellites.co.uk

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.

Pressing Setup on the back panel of the receiver will display the ROM version number.

Pressing Shift then Menu will display the channel information: channel number, frequency, channel name (from the SI data), audio type, and bit error rate.

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

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.

1. Unplug the MAC board from the card reader board. Plug the MAC board directly into the receiver motherboard.
2. Desolder the left and right audio wires going from the MAC board to the PAL board.
3. Disconnect “VBC” and “VI” from the PAL board. Connect them together.
4. 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.
5. 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.

The Trac ROMs support three types of LNB:

The above assumes a receiver tuner range of 0.95 to 1.75 GHz.

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.

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.

Tatung documentation:

• Tatung TRX-2801 Service Manual
• TRX-2801 main firmware ROM (Intel D87C257) version TUKR1.3

I've created a LIRC IR remote configuration file for the TRX-2801:

• tatung_trx-2801.lircd.conf.txt

To enter Test mode:

1. Hold the TEST key on the local keypad while powering the receiver on.
2. Keep the TEST key depressed until the LED display shows H (standby).
3. Press the Standby button to wake the receiver. The receiver will display scrambled pictures when not authorised, instead of blanking the video – this is intentional.
4. Press MENU to display the main menu.
5. Press 6 to enter the Test menu.

The receiver will remain in test mode until it is switched off and back on again.

• Philips STU902 service manual (thanks to freeservicemanuals.info)
• Philips STU902 firmware ROMs:
  • version PhiR209 (thanks to fsphil)
  • version PhiR211
  • version PhiR213 (thanks to fsphil)

ACM diagnostics – press Menu, then the 0 (zero) key.

Transworld Satellites made several D2MAC modifications for the STU902. These ranged from an EPROM-only mod which only allowed access to free-to-air channels, right up to a Eurocrypt-capable D2MAC mod with a front-panel card-slot.

I'm looking for information and instructions for the Transworld mods, as I currently have a Transworld-modified receiver which powers on, displays “00” then “01” on the display, but otherwise doesn't work. If you have any details on these upgrades (or others), please contact me by email.

The main CPU is a Philips 80C31, running at 11.0592MHz.

The PSEN (program store) is connected to the 27C512 program memory EPROM.

The XDATA (external data) memory is mapped as follows:

• 0000 to 1FFF: MK48H64 RAM “7501”, not battery backed. 8 Kbytes.
• 2000 to 7FFF: RAM shadow copies (undefined)
• 8000 to FFFF: Subdecoded by 74F139 “7512”:
  • 8000 to 9FFF: Display Segment Latch “7514”
    • Bit 0: G
    • Bit 1: F
    • Bit 2: E
    • Bit 3: D
    • Bit 4: Red and Green LEDs (Red = DIG1, Green = DIG2)
    • Bit 5: A
    • Bit 6: B
    • Bit 7: C
  • A000 to BFFF: Display Common, Switches and Control Latch
    • Bit 7: → C7
    • Bit 6: Digit 1 / Red LED
    • Bit 5: Digit 2 / Green LED
    • Bit 4: STDBY → D6
    • Bit 3: RESET ⇒ B4, C5
    • Bit 2: Standby switch, 0 to sense on P1.3.
    • Bit 1: Service link, 0 to sense on P1.3.
    • Bit 0: Setup switch, 0 to sense on P1.3.
  • C000 to DFFF: IMBUS Register Read
  • E000 to FFFF: Access Control Module
    • A11: Register Select
    • A12: Read/!Write

Interrupts:

• INT0: Infrared remote
• INT1: Access Control Module