Search found 1339 matches

by robcfg
Wed May 05, 2021 6:19 pm
Forum: Dragon Hardware
Topic: Diagnosing a faulty CoCo2
Replies: 8
Views: 460

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: 92

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: 460

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: 460

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: 10
Views: 466

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: 460

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: 460

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: 686

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...
by robcfg
Mon Mar 22, 2021 12:14 am
Forum: Hints and Tips
Topic: Help running Basic programs from Rom
Replies: 3
Views: 686

Re: Help running Basic programs from Rom

I've tried following John's tutorial but makes no difference whatsoever.

Also if it were the case, why is it that the driving test rom works with that minimal loader?