Search found 1350 matches

by robcfg
Wed May 05, 2021 6:19 pm
Forum: Dragon Hardware
Topic: Diagnosing a faulty CoCo2
Replies: 8
Views: 1092

Re: Diagnosing a faulty CoCo2

Success! I tried the CoCo 2's 6847 on one of my Dragon and the composite video output was dead. Then I put the Dragon's 6847 in the CoCo 2 and lo and behold, we have a fully working CoCo 2! CoCo2_11.jpg CoCo2_12.jpg Case closed! (Literally and metaphorically :mrgreen: ) Now, I need a new 6847. And I...
by robcfg
Fri Apr 30, 2021 8:13 am
Forum: Software Requests
Topic: Some software disks that I just transferred to DSK
Replies: 3
Views: 343

Re: Some software disks that I just transferred to DSK

Just create a post in the Uploads section of the forum and post or link your disk images there.
by robcfg
Fri Apr 23, 2021 6:17 pm
Forum: Dragon Hardware
Topic: Diagnosing a faulty CoCo2
Replies: 8
Views: 1092

Re: Diagnosing a faulty CoCo2

Hi Ciaran! Does CC:10 prevent the machine from booting correctly? Because I've managed to load software on the CoCo2, so my guess is that it initialises properly. Here's the memory assortment on my CoCo2: CoCo2_10.jpg I see a chip different from the rest, but don't know if it's different enough :mrg...
by robcfg
Fri Apr 23, 2021 5:35 pm
Forum: Dragon Hardware
Topic: Diagnosing a faulty CoCo2
Replies: 8
Views: 1092

Re: Diagnosing a faulty CoCo2

Well, results are in! CoCo2_08.jpg The video via RF works enough to get a picture, so that's good news! On the other hand, knowing that this works, and that signals from the PIA are correct as far as I know, the MC6847 must be damaged, so I guess it's time to get the desoldering braid and a spare so...
by robcfg
Thu Apr 22, 2021 10:41 pm
Forum: Dragon General
Topic: DRAM data retention time
Replies: 18
Views: 2067

Re: DRAM data retention time

Can it be run from a cartridge?

It may be way easier to program an eeprom or run it from the DragonMMC.

And, did I read 256KB Dragon? :mrgreen:
by robcfg
Thu Apr 22, 2021 4:59 pm
Forum: Dragon Hardware
Topic: Diagnosing a faulty CoCo2
Replies: 8
Views: 1092

Re: Diagnosing a faulty CoCo2

Hi Stew! It never crossed my mind that the VHF signal could be a problem. Thing is, my TV set detects the signal, and I can clearly see when the computer is on or off because the screen is completely black or as I showed above. Does the Tano Dragon have the RF output? If that's the case I could try ...
by robcfg
Wed Apr 21, 2021 6:12 pm
Forum: Dragon Hardware
Topic: Diagnosing a faulty CoCo2
Replies: 8
Views: 1092

Diagnosing a faulty CoCo2

Hello everyone! I'm trying to diagnose a 16Kb Korean made CoCo2 I got from a friend long ago, and as him before me, I'm quite stuck :lol: So, here's the patient: CoCo2_01.jpg And here's the symptom: CoCo2_02.jpg The screen is grey because it's a NTSC machine on a PAL tv. What do I know? 1) The machi...
by robcfg
Mon Mar 22, 2021 11:06 pm
Forum: Hints and Tips
Topic: Help running Basic programs from Rom
Replies: 3
Views: 928

Re: Help running Basic programs from Rom

Ok, analysing the code in the rom I mentioned, it turns out that the first line does the following: 1 POKE28,239:POKE32760,123:GP=0:RET=4:POKE32736,4:POKE32739,0:FER=2:POKE&H120,20:DEFUSR0=32720:CLEAR600,32720:P=PEEK(32761):IFP=1THENGOTO992:ELSEGOTO1450 So I guess I can have that on the asm loader l...