Search found 424 matches

by sorchard
Sat Jun 20, 2020 1:21 pm
Forum: Dragon Hardware
Topic: ?OM errors
Replies: 10
Views: 358

Re: ?OM errors

It's worth sounding out the seller to see if they are willing to do anything. It may well have been working when last used, but has deteriorated with time, and being rattled around in the back of a van was the last straw. It's impossible to know for sure. I should have said initially that the first ...
by sorchard
Tue Jun 16, 2020 3:38 pm
Forum: Dragon Hardware
Topic: ?OM errors
Replies: 10
Views: 358

Re: ?OM errors

The extra resistors are fairly normal and are tweaks to the display. I've seen these on quite a few boards. As for the fault, there are many possibilities. It could be a RAM IC, ROM, CPU or SAM as previously mentioned. It could also be a bad power supply. Try lifting each socketed IC a little and pu...
by sorchard
Sat Jun 06, 2020 9:13 pm
Forum: Dragon Hardware
Topic: Video quality revisit
Replies: 1
Views: 122

Re: Video quality revisit

The colour subcarrier crystal is usually just to the left of the power connector, and just under the crystal there is a load cap C7. On some boards this is a 22pF trimmer and can be adjusted to fine tune the subcarrier frequency. If it's a long way off then the display device might struggle to lock ...
by sorchard
Sat Jun 06, 2020 11:40 am
Forum: Dragon General
Topic: XRoar Windows packaging - good? bad?
Replies: 6
Views: 326

Re: XRoar Windows packaging - good? bad?

I tried the msi on my work laptop which has Win7. The desktop shortcut works, as does the link to the manual via the start menu. The installation ended up here: C:\Program Files\6809.org.uk\XRoar snapshot 0.35.15208 I was able to put roms in either of these folders: C:\Users\Stew\AppData\Local\XRoar...
by sorchard
Wed Jun 03, 2020 9:05 pm
Forum: Dragon Hardware
Topic: Opening dragon joysticks
Replies: 2
Views: 132

Re: Opening dragon joysticks

My first thought was that there are often screws hidden under the rubber feet, but unfortunately that doesn't seem to be the case with Dragon Data joysticks. I think you're probably right and the two halves of the case are glued together. If you're lucky then some gentle heating might soften the glu...
by sorchard
Tue May 26, 2020 4:00 pm
Forum: Dragon General
Topic: Comparison of Dragon mass storage options
Replies: 10
Views: 679

Re: Comparison of Dragon mass storage options

Interesting Stew - so have you added a ear and remote socket, and made the uDW play out the cassette loadable Drivewire dweeb? That's pretty much the size of it, though I just fit the ear socket and chose a switching type, such that plugging in the cable triggers the file playback. This scheme also...
by sorchard
Sun May 24, 2020 12:23 pm
Forum: Dragon General
Topic: Comparison of Dragon mass storage options
Replies: 10
Views: 679

Re: Comparison of Dragon mass storage options

Perhaps this should! http://tormod.me/udw.html - does anyone here own one? Yes, I have one of those and am very happy with it. For best results it needs some form of rom support, such as Tormod's modified BASIC rom, or (I imagine) a DriveWire extended DOS. To make it more convenient to use, I added...
by sorchard
Thu May 14, 2020 12:19 pm
Forum: Dragon General
Topic: Dragon power board problems!
Replies: 9
Views: 918

Re: Dragon power board problems!

I assume those were all bare-machine, no disk interface and on factory original 4700uFs? That's right, the PSU boards are factory original, and no cartridges or other devices were plugged in other than a monitor. It would have been nice to get some scope captures of the ripple voltage but I can't g...
by sorchard
Tue May 12, 2020 12:21 pm
Forum: Dragon General
Topic: Dragon power board problems!
Replies: 9
Views: 918

Re: Dragon power board problems!

An LDO regulator would certainly make the supply a bit more forgiving in the event of sagging input voltage. There isn't much to pick between them, any 3 Amp device should work. Just check the datasheet carefully for notes regarding the output capacitor as they have a nasty habit of oscillating if t...
by sorchard
Tue May 12, 2020 12:11 pm
Forum: Dragon General
Topic: A 6809 Single Board Computer
Replies: 22
Views: 2700

Re: A 6809 Single Board Computer

Apart from checking that the ICs are getting the correct supply voltages, I would be a bit stuck without an oscilloscope. I would want to be looking for activity on the chip select signals to the rom/ram/acia to confirm that the firmware is running.