admin wrote:There are 3 different types of Mark I Dragon 32 boards (All the MK 1 boards have the same layout with the exception of the RAM area:
- The original 16K board with 16K Piggy Back, labelled as (c) Dragon Data Services Ltd - Issue 2. Only circa 10,000 of these were produced before production moved to a 32K machine.
The ones that where supposedly origionally going to be 16K machines, until DD got wind of Sinclair releasing the 48K spectrum....
The OKI board, labelled as (c) Dragon Data - Issue 2, using 8 OKI 16x16K RAM to give 32K.
Those are the half good 4164 64Kx1 chips, the 48K spectrum also uses them for it's bank of 32K RAM, these boards are easy to upgrade to 64K by simply replacing the RAM chips with 4164s and doing the decoder mod, shame the OKIs where not socketed.......
I believe the above two boards are actually the same mainboard.
The Siemens board, labelled as (c) Dragon Data - Issue 2, using 16 Siemens 16x16K RAM to give 32K.
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Ahh the one with the stacked 18 pin chips.
There are 2 types of Mark II board:
The Mark II Board, labelled as DRAGON DATA LTD CPU UK 32K MKII - Issue 5 or Issue 6 - with the SAM mounted horizontally to make room for 16 RAM chips on the main board.
There does not appear to have been an Issue 1,3 or 4 board put into production.
I'll have a look see if there are any significant differences. (If I have both types of board), which will involve opening a few dragons...
The PSU board for the Dragon 32 comes in Issue 1,2,3 and 4. Issues 1 and 3 will be the most common and Issue 2 was withdrawn due to a modulator compatibility problem.
Not sure which versions I have I'll have to have a look at the ones that are not in machines (first) and will take some piccies.
As for the Dragon 64, I used to think there was only 1 board but recently I have seen two different D64 boards.....
I think both of mine are the same but then I've only actually seen the inside of two dragon 64s, are the Dragon 200 boards the same as the Dragon Data ones ?
Cheers.
Phill.