Despite the lockdown, I've had enough chores lined up to keep my evenings and weekends pretty much full until today. The time is long overdue for some tinkering...
First
thing on the agenda was changing the springs on my Vectrex joypad. This
was actually a lot fiddlier than I expected, and took quite a while.
The shiny new springs I got off eBay certainly make the centring tighter.
But there's still a wobble zone of a couple of mill around the middle, where the stick moves in and out and round about a bit without engaging. Is that normal? Kindof
feels like there should be a washer or something in there to hold the
ball-bearing on the joystick steady?
While I was in there, I gave the button contacts another going over with some contact cleaner and a cotton bud. They all worked before, but button 4 would sometimes fail to register if you hit it off centre. Seems to be better now.
Next was to get the back off and twiddle with the various screen adjustment pots and centring magnets. Moving the latter helped nudge the picture back towards the middle. Perhaps it had been shaken out of line in transit? The bolt holder in the pic below certainly had been. I knew it was missing from previous explorations, but only just found it today, stuck deep down in the gubbins. When I get some suitable glue, I'll try to stick it back in place.
Last on the list was a job I've been putting off for fear of mucking it up - the debuzz mod!!!!
I've had the amp and the resistors (recommended by Joe34) for a while now. Or at least I thought I had. Unfortunately, when I unravelled my roll of resistors it turned out that rather than the varied assortment I thought I'd ordered, it was actually a full strip of 100 Ohm parts. Gaaaaargh! Instead of waiting for some new ones, I decided to press on any way.
Before starting, I rewatched the videos posted elsewhere on UKVac by Nes4Life and VirtVic.
To save time, I followed VirtVic's example, and only took enough of the wires off to let me twist the bottom pcb round and work on it while still partially attached.
Top tip. Before taking out the 5 screws that hold the pcb in place, be sure to gently prize off the volume knob from the front of the console. I couldn't figure out what was holding the board in place until I gave it a (gentle) yank, and heard the knob rattle onto the floor. Whoops!
After reading various comments on the process from all over the interwebz, I knew the mod was unlikely to eliminate 100% of the buzz. But to maximise the level of success I decided to:
1) Use some old-school shielded RF cable.
2) Keep the wires as short as possible (I trimmed them down even further after this).
3) To help with no 2, and also keep the wires as far away from the CRT as possible, I drilled a small hole in the speaker casing to re-route the speaker wires.
Before anyone says anything, I know my soldering is pants. And yes, I did manage to singe some non-essential plastic parts. It would have helped me enormously to have one of those soldering holder do-dahs. However, it's done now, and job (seems to be) a good-un!
The result?
Before its operation, my Vectrex had a full-on throaty buzz, amplified to the max.
Now, unless you put your ear down beside the speaker, it's hard to hear any buzz. As expected, it's still there a tiny bit, but it really is hardly noticable, even at full volume.
NB: Before the operation, the highest volume was LOUD to the point of distortion. Now, it's still plenty loud enough, perhaps even too loud for a quiet room. Whether it would still be loud enough in a noisy room remains to be seen. But I suppose there's some scope for twiddling with the pot on the amp?
So, many thanks to the guys who posted their tips and videos on here.
If anyone else is planning the debuzz procedure who perhaps hasn't done a lot of soldering, or isn't too familiar with the insides of a Vectrex (like me), what VirtVic and Nes4Life make look easy, could easily drag out to an hour or two. Especially if you get distracted cleaning some of the grime of the PCB.
***
PS: I've only just noticed recently that my Vectrex is missing its two front feet! I've stuck on some generic pads in the meantime. But does anyone know where to get some more authentic replacements?
RygarR2020-05-03 17:19:34