Graham Downey @grahamdowney.com · 09/09/2026Scored at the giveaway table at the computer science offices on campus! 020
Graham Downey @grahamdowney.com · 07/09/2026The Buick is happy once again! New rear shocks means it no longer feels like chopping waves on the open sea. 110
Graham Downey @grahamdowney.com · 29/08/2026A simplified version of the schematic would actually look more like this. If you notice V1a and V1b actually look quite similar now. Essentially when you switch on the modded it changes V1a from a cold clipper to more of a high gain boost like V1b. 100
Graham Downey @grahamdowney.com · 29/08/2026Looking at the full schematic again we can see at point 3 on V1b there is a 0.68uF bypass cap. Smaller values like this cut low frequencies of the signal and boost only the mids and highs. The 150uF installed on V1a is large enough that it boosts the entire frequency range down to around 1.6hz 100
Graham Downey @grahamdowney.com · 29/08/2026If we ignore the bypass switch we can draw these components into the schematic to better visualize what this mod really is. This is a side-by-side of the stock circuit and the modded one with the switch enabled. 100
Graham Downey @grahamdowney.com · 29/08/2026Now the question is what exactly are the resistor/cap combo on the side of the PCB supposed to do? These are connected at the top of R1 on the board, which connects the cathode on the V1a cold clipper to ground. We can see where this is on the schematic. 100
Graham Downey @grahamdowney.com · 29/08/2026The only thing really changed on this side of the circuit is the push/pull function acts as an on/off switch between the posts on the back of the pot. Pushed in the switch is off and the mod is disconnected. Pulled out and the components on the blue wire connect to ground. 100
Graham Downey @grahamdowney.com · 29/08/2026For anyone familiar with the inner workings of a JCM 800 you'll probably notice most of the amp was left pretty bone stock for a late 80s Marshall circuit. There's only the push/pull pot added and a parallel resistor/cap combo hanging off the right side of the board. 100
Graham Downey @grahamdowney.com · 29/08/2026The previous owner of the amp had it modded by Gar Gillies of Garnet Amplifier fame back in 2005. For those unfamiliar he was the tech who built the amps for the Guess Who in the 60s/70s and designed that signature "American Woman" lead tone. 100
Graham Downey @grahamdowney.com · 29/08/2026Finally got around to opening my JCM 800 to clean the pots and actually see what mods the last tech did on it almost 21 years ago! 110
Graham Downey @grahamdowney.com · 24/06/2026After 4 days of what felt like hitting my head against a wall we were able to roll back the Mac one version of MacOS. 030
Graham Downey @grahamdowney.com · 01/05/2026My game's map format is more memory efficient than yours :P 110
Graham Downey @grahamdowney.com · 26/04/2026Super satisfied with how this parallax scrolling turned out 020
Graham Downey @grahamdowney.com · 25/04/2026It's just called "IR Remote". Has a dictionary of common TV models you can load remotes for and also define custom IR patterns for unsupported ones. 000
Graham Downey @grahamdowney.com · 25/04/2026Got this Thinkpad 390E with docking station for $6 due to the broken screen hinge. Seems to work but it has a BIOS-set password so I can't boot it to test further. Anyone know an easy way to reset/bypass the password on these? 000
Graham Downey @grahamdowney.com · 22/04/2026Step 1 of my game for the DOS gamejam -- space physics! I decided to try VGA mode Q for fun. 256x256 resolution with 256 colors. Runs rather smooth at 2000 cycles in DOSBox. 140
Graham Downey @grahamdowney.com · 01/03/2026Shout out to my Galaxy S5 for still working long enough to open the IR remote app and fix it 120
Graham Downey @grahamdowney.com · 01/03/2026Days like today I wish smartphones still had IR blasters. My TV is stuck in french and to change it back or change the channel you need the remote which I haven't seen in a decade lol 220
Graham Downey @grahamdowney.com · 03/06/2025This 25 year old copy of Microsoft Word knows the difference between Canadian and American spellings. Why can't anything built using Chromium?? 000
