I didn't find this in the archives. This is the original supplementary manual shipped with the Dragon 64, describing the additional features over the D32.
-- Rolf
Search found 299 matches
- Sat Aug 22, 2009 9:25 pm
- Forum: Uploads
- Topic: Doc: Dragon 64 Supplement
- Replies: 0
- Views: 3883
- Tue Aug 11, 2009 9:24 pm
- Forum: Dragon General
- Topic: EPROM Programmer?
- Replies: 10
- Views: 7600
Re: EPROM Programmer?
I'm sorry that I cannot help here. The schematics and the address ranges in the pictures indicate that this is two 8k PROMs in a 24 pin package. I am unable to find any EPROMs that are compatible with those specs. AllDatasheet (http://www.alldatasheet.com/) is a good place to start if you want to di...
- Mon Aug 10, 2009 8:35 pm
- Forum: Dragon General
- Topic: EPROM Programmer?
- Replies: 10
- Views: 7600
Re: EPROM Programmer?
I have checked the diagrams and photos again, and it looks like I was terribly wrong regarding the D32 PROMs. These PROMs are 8k large but come in a 24 pin package. I am unable to find an EPROM that meets those specs. It is probably still pretty easy to replace the D32 PROMs with standard EPROMs by ...
- Sun Aug 09, 2009 9:56 pm
- Forum: Dragon General
- Topic: EPROM Programmer?
- Replies: 10
- Views: 7600
Re: EPROM Programmer?
No, unfortunately they are of no help. All pictures with good enough resolution shows ROMs marked with "Dragon Data" and no part numbers. I'll take another shot at decoding the diagrams tomorrow...
- Sun Aug 09, 2009 9:22 pm
- Forum: Dragon General
- Topic: EPROM Programmer?
- Replies: 10
- Views: 7600
Re: EPROM Programmer?
I've given the schematics a try, but it is really hard to read the part numbers and pin numbers. However, it looks like the D32 contains two PROMs both with 13 address lines. That means two 8k PROMS, giving a total of 16k. Given my problem with reading all the pin numbers, I can't be completely sure...
- Sun Aug 09, 2009 9:11 pm
- Forum: Dragon General
- Topic: Extra PCB fitted to Dragon 32
- Replies: 14
- Views: 10629
Re: Extra PCB fitted to Dragon 32
Don't know what the purpose of the board is but both additional ICs are quite standard logic gates. SN74LS74 is a pair of D-type flip-flops (basically 1 bit memories) and SN74LS32 contains four 2-input OR gates. My guess would be a "patch" to compensate for an error on the main motherboard, but that...
- Wed Aug 05, 2009 10:29 pm
- Forum: Dragon General
- Topic: EPROM Programmer?
- Replies: 10
- Views: 7600
Re: EPROM Programmer?
The Dragon 64 uses two 16k PROMs. These PROMs are compatible with the 27128 family of EPROMS. You can get these EPROMS from Maplin (http://www.maplin.co.uk) or ELFA (http://www.elfa.se) or similar. Some vendors don't seem to carry the 27128 anymore, but a pair of 27256 (32k) EPROMS can also be used....
- Mon May 04, 2009 9:24 pm
- Forum: Dragon General
- Topic: Question about D32 circuit diagram
- Replies: 12
- Views: 8460
Re: Question about D32 circuit diagram
I did a similar trick back in the good old days. I simply removed LM1889 from its socket. This disabled color, but also resulted in a much steadier monochrome display. I did it on both my D32 and D64 with good results. LM1889 has been socketed (not soldered) on all Dragon models that I have seen so ...
- Wed Apr 08, 2009 9:06 pm
- Forum: Discuss This Site
- Topic: We missed a few posts, didn't we?
- Replies: 6
- Views: 8361
Re: We missed a few posts, didn't we?
I'm also back after having re-created my account. Why where the accounts closed? I'd be surprised (in a positive way) if the community is so large that there is a need to purge the user database of inactive users...
-- Rolf
-- Rolf