Data East 520-5047-00 – DMD Power Supply
Soon after working on the Bram Stoker Dracula DMD Driver Board – I received a Data East 520-5047-00 DMD power supply board for a Data East. The board kept blowing the F7 fuse. On initial inspection there seemed to be a few issues with the board that needed to be resolved. The game wasn’t delivering any 68V through the circuit, so this section needed to be repaired.
Compatibility of the Data East 520-5047-00
The board I received was a Data East 520-5047-00 revision C – which is supposed to be used in the small DMD (Dot Matrix Display) games. This board however came out of a large DMD game – Lethal Weapon 3. It is noted that some future versions of this board are backwards compatible – but I cannot find any usage of this particular board being forward compatible, probably what caused this issue.
Visual inspection and issues
The 1n4004 at D7 was destroyed, so this needed replacing. Whilst in there, it made sense to simply replace D5 also as it was the same component type and I had hundreds on a reel.
Pins, Pins, Pins
The pins on this board had been messed with poorly too, with wire used as a bridging connector, note the pin and wire through the hole next to my finger… nice work.
The central pins aren’t used on this game. I desoldered and removed further chunks of wire between the pins. With the old ruined pins taken out, the plug was put back to a usable condition. I wish I had taken more pictures of the wire pin, it was quite a bit of engineering.
On further inspection, the capacitor at C10 was bulging quite badly. After removing it from the board and a quick test with the DMM, my suspicions were confirmed. Two pins desoldered, a new cap popped in and job done.
The resistors on the board all measured out to within specification as did the 68v Zenner Diode. The 3.9V Zenner Diode did not. so this meant replacement of the Zenner Diode (1n5228). Whilst doing this, the PNP Transistor (MPSA92) and NPN Transistor (MJE15030) also got changed.
The MPSA42 and MJE350 were also broken and burnt, so they got replaced too.
The board was now ready to be sent back to its owner, whilst it cannot go back in the Lethal Weapon 3 as far as I am concerned – it is ready to have as a spare or be sold on once more.
If you have any experience of forwards compatibility of this board working – please let me know in the comments section.