So, Double Dragon had issues loading on a Tape Drive I'd acquired. It had come in a mouldy box, so I had a hunch that the drive itself would need a thorough clean and alignment.
There are multiple alignment tools, downloadable as disk images or PRG files. I could copy these onto my SD2IEC, but there was an issue: the SD2IEC gained power from the Datasette port which was now in use by the Datasette drive itself!
Powering the SD2IEC from the Datasette Cable
Fortunately, the Datasette plug has a screw that makes accessing the internal pins very easy. I opened it up, taking note of the cracked, flimsy plastic, and inspected the contents.
The green wire, pin 2, is the +5v that we're after. Bare back some plastic on the wire so we can solder to it. I found a male+female standard round DC power socket to use. Make sure the female is on the 'power' side, otherwise you'll have a potential for shorts if there is exposed bare metal with current flowing through it. Of course, the outer metal is ground, but still better to be safer than sorry.
From here I soldered on the plug and grinded out some plastic from where the main cable feeds in. This allowed the plug to hang out the end. Not the cleanest job, but it worked quite well. I sorted wanted to feed it out the side where the ground wire is... but I hadn't left enough length.
Next, on the SD2IEC end, bare some wire also. Grab the plug and solder it on, then use some form of insulator to tidy it all up. Nothing a little duct-tape can't fix.
Everything was plugged in and good to go!
Cleaning the head
Everyone recommends alcohol (isopropyl) wipes for this. The wipes have the benefit of leaving little residue and drying cleanly. You'll find that KFC wipes are also usable.
Take the swab out of the packet and wipe the heads, specifically the central metal one. I didn't actually know which way to wipe, or how much pressure to apply. So just be gentle and attempt to remove any visible dirt. Don't put a tape back in until everything is try.
Aliging the head
I copied them both onto the SD2IEC and then loaded them via the file browser. Cassette Azimuth is easy to work with. Load it up and then hit play on your tape. If nothing is happening then you'll need to start adjusting the player already. If you see data, and it's erratic, then you'll also need to adjust. The goal is to have straight vertical lines.
To actually do the adjusting, there is a tiny screw-hole above the rewind button that a small jeweller's screw driver will fit through. When the tape drive is playing, the hole lines up with the head adjustment screw. Turn this screw all the way clockwise (not too much pressure!) and then turn back in small increments as required. Pause between turns to let the screen update with the new readings.
You can hit F1 to get the guide-lines for the data. I couldn't work out if the data lines were meant to draw over the top, or in between, or where... but at least I got them vertical!
Here's the same process with Minimal Head Align. The app is much more raw; it starts off with a screen full of garbage which starts refreshing once you start feeding it data from the tape drive.
Back to Double Dragon
I had assumed that all the loading issues were from a dirty/misaligned head... so I thought I'd try the game again now that the tape was producing cleaner, more vertical lines on the test programs. I didn't have much faith... but it worked! It took just as long as last time, but this time I got to the first level!
The graphics are intense... hah. Controlling the character was hard at the start... then I realised it was because my controller probably hadn't been used in a decade. I'd found a sega mastersystem controller at a second-hand shop over the weekend. Works perfectly.
So as the game was loading, it got to the point right before the title and asked me to reset the counter to 0. Turns out this is so that, when you die, you know where to rewind the tape to.
From there you rewind to zero, press play... wait for the load and then have another go. I might try source the game on floppies to see if the extra data capacity allowed for a different version. Hmm... then again if this review is anything to go by, then there's no hope.