Dragon survey, what to ask for?

[Vato]

Here are a few more pictures:

I will post some more once I have ploughed my way through the loft and taken the pictures.
There should be a 1233 modulator, Thomson 6809 and Siemens RAM and what ever else I come across.

Has anyone seen any other Power board with Reg 3 bolted to the heatsink?

Gareth

Thanks Gareth!
Nice to finally see a Tano from within!

Vato

[munkeyboy]

I have got a few more pictures, these are from a Dragon 32 which I will add to the database once I have carried out the speed POKE.

Thank you Zephyr for the information that a couple of your D32's have Reg 3 bolted down, the only one I have seen was in a TANO. I will post my next question on this in a new topic.

P1000211.JPG (100.9 KiB) Viewed 8347 times

[zephyr]

Fantastic! The 'Siemens' board, with its 8 Siemens HYB-4232 (double 16K) RAM chips. And, a picture of the Thomson EF6809E processor.

Here's the data sheet...

[zephyr]

I think these are basically the same as the boards that were fitted with OKI chips. Any chance of a picture of the whole board?

Edit: It would be nice to have good pictures of all four boards.

[zephyr]

That picture is also a really good example of the OKI RAM configuration. Alastair, is your RAM configuration like this?

Yes, though in my case the OKIs are labelled M3732L-20RS 2Y110.

I thought so! I'm really surprised that it doesn't run at double speed though. I have four Dragons with these boards fitted, and they all run exceptionally well at double speed. All of my OKI boards are marked as 'issue 2' and are fitted with the MK1 (UM1286) and MK3 (UM1287) power boards. Perhaps its just a slow ROM chip, or maybe its something as simple as a couple of extra capacitors (like the early CoCo's) thats causing the problem. Are both of your ROM chips socketed?

Edit: I have just been looking at all four of my OKI boards, and I noticed that although they all look identical, one of them has the jumpers set in positions 2,4,6,8,10 rather than 1,4,6,8,10. I tried swapping the first (leftmost looking from the front) jumper to position 1 like all the rest, but the Dragon didn't work correctly aferwards. After carefully comparing it with all my other OKI type boards, I can't see any difference. Can anyone explain this?

[munkeyboy]

Here is the full 'Siemens' main board

P1000212.JPG (98.31 KiB) Viewed 8293 times

[zephyr]

Thanks! This picture now shows a Motorola MC6809E processor rather than the Thomson above. Have you got two Dragon 32's with 'Siemens' boards fitted?

Edit: Looks like I was wrong about these being the same as the OKI type boards. Still issue 2, but I can see that it has some of the mods that were present on the later 16x16 type boards..

[Alastair]

That picture is also a really good example of the OKI RAM configuration. Alastair, is your RAM configuration like this?

Yes, though in my case the OKIs are labelled M3732L-20RS 2Y110.

I thought so! I'm really surprised that it doesn't run at double speed though. I have four Dragons with these boards fitted, and they all run exceptionally well at double speed. All of my OKI boards are marked as 'issue 2' and are fitted with the MK1 (UM1286) and MK3 (UM1287) power boards. Perhaps its just a slow ROM chip, or maybe its something as simple as a couple of extra capacitors (like the early CoCo's) thats causing the problem. Are both of your ROM chips socketed?

I'll need to check the ROMs (which are they), I'll also see if I can borrow a digital camera so that I can upload some pictures. By the way, it's not the only OKI Issue 2 that cannot take the double speed poke, if the owner of the Dragon 32 with ID 81 at http://www.studio68.no/surveys/dragon/default.asp speaks up then they'll be a second person who could answer questions.

Edit: I have just been looking at all four of my OKI boards, and I noticed that although they all look identical, one of them has the jumpers set in positions 2,4,6,8,10 rather than 1,4,6,8,10. I tried swapping the first (leftmost looking from the front) jumper to position 1 like all the rest, but the Dragon didn't work correctly aferwards. After carefully comparing it with all my other OKI type boards, I can't see any difference. Can anyone explain this?

I've read that you have to be very careful with these jumpers as you can cause damage if you do not know what you are doing. I wouldn't know what I would be doing, so I've left them well alone.

[zephyr]

I'll need to check the ROMs (which are they)

The ROM chips are IC17 and IC18.

I'll also see if I can borrow a digital camera so that I can upload some pictures.

Thanks!

By the way, it's not the only OKI Issue 2 that cannot take the double speed poke, if the owner of the Dragon 32 with ID 81 at http://www.studio68.no/surveys/dragon/default.asp speaks up then they'll be a second person who could answer questions.

I saw that, but I don't know who owns it.

I've read that you have to be very careful with these jumpers as you can cause damage if you do not know what you are doing. I wouldn't know what I would be doing, so I've left them well alone.

Don't worry, I checked first to make sure that it didn't change any voltages.

A lot of D32s of 82-83 vintage were built on 'Issue 2' mainboards. These had room for only 8 chips on the mainboard, and often 8 OKI 3732s were fitted (see above). However, they are even more common in their (16 x l6k) versions, when the 8 extra memory chips were added in sockets above the others; or else a small subsidiary ’patch' board was added, containing l0 RAM chips end the 74LS244 memory buffer - 6 RAM chips remained on the mainboard, with connections to the patchboard taking up the space normally occupied by ICl,IC8 (RAMs) and lCl6 (74LS244).

To facilitate their use as either (8 x 32k) or (16 x 16k) boards, 5 jumpers were fitted, just in front and to the right of the power supply connector (looking from keyboard!). The positions of these jumpers are numbered on the board from 1 to 10 (odd positions are at back), and they perform the following functions (which, if you are in any doubt, you should verify!):-

a) The first (leftmost) jumper 'controls the inclusion, or not, of an inverter in the RASl/Z7 signal line. In position 1 there is no inverter, in position 2 there is.

b) The second jumper controls the voltage on pins l of the RAMs. In position 3 it is -5v, in position 4 it is +5v.

c) The third controls the voltage on RAM pins 8. In position 5 it is 12v, in position 6 it is 5v.

d) The fourth controls the use of RAM pins 9. In position 7 there is +5v on the pins, in position B it is RASl/Z7.

e) The fifth (rightmost) jumper controls the voltage on pin 12 of IC35. In position 9 this is 5v, and in position 10 0v.

[munkeyboy]

Hello, please let me apologise for the 'mis-information'. The Siemens board is on a different Dragon 32 to the Thomson 6809 CPU. My mistake - sorry!
I will have to check my own database for irregularities
It will take me some time to check, photograph and high speed POKE each Dragon from scratch, but at least I will know that the information is absolutely correct.
I have over 20 Dragons (most of them from my brother who used to service them, as well as my own from 1983, plus a few from ebay) and I want to submit the correct information to Vato's database so that a better overall picture of the Dragon's production history can be collated.
So I think my school report should show -
'Tries hard, but needs to pay more attention to detail'.

Gareth