Restoring an old bandsaw

I inherited an old bandsaw from my grandfather which worked but needed serious TLC. The wooden stand was trashed and the belt mounting was non-existent. Time to make a new one. Didn’t help I had to fit it in the back of a 350z..

Fixing the wiring

Before i start with a new stand, I had to address the awful wiring. I replaced basically all of it with modern wiring, luckily the motor cover had a wiring diagram on it to determine what direction the motor spins so I could reverse it to have a more compact stand.

New frame and adding a sander

I opted to use 18mm plywood and 100x50mm timber with locking caster wheels to make it easier to move around. It is all mounted with T-nuts to make it easier to dismantle. I added a new blade at the same time, but I had to move the cover bolts to get the shorter, thicker blade installed. 

I also added a belt sander on the other side since I reverse mounted the motor under the machine. Having the lower space underneath also gave me space to put my air compressor as well making it an all in one portable setup. The only thing that is left is to remove some of the vibration which I think is belt or blade tension related.

No Red or audio on a Sony PVM

So after moving house, my PVM developed an issue where it would intermittently show the red in the picture. It took a while to figure it out as I thought it was just a loose connection but it seemed to be something internal.

The symptoms and fix

After I realised it was an internal issue, I finally could reproduce it by pushing up on the back of the casing and could introduce the issue consistently, this proved it was either a loose connection or a cracked solder joint and not a bad red beam in the CRT itself.

Once I figured that out.I had to find a way to isolate the issue, I ordered some cooking chopsticks on AliExpress so I could poke around the board while it was powered on without risking shocking myself. After reading the schematics and finding the likely area, I finally found that it was the daughter board carrying the signal that was socketed into the mainboard. I powered it off and removed it, put contact cleaner in there and put it all back together and the problem went away.

An Audio side quest

While I had it all part I figured I would address the missing audio. I did replace a few of the caps in the audio section with no success and determined it was the op-amp itself. I ordered a new one and the sound all came back in its mono glory.

USBC charging for a PS3 Controller

Everyone knows how annoying it is to charge PS3 controllers, you have to have them plugged into a PC or the PS3 itself powered on, well I attempted to work around that.

The solution

A while ago, I came across this Github project thats aimed to solve this issue by using an ATmega chip and USBC. The PS3 controllers use USB handshakes before they will start to charge, which is why only a PC or PS3 will charge them. This github project, uses the ATmega chip to initiate the USB handshake and the start charging up to 4 controllers via a USBC input.

Safe to say, the project was more annoying that I expected it to be. It uses 0402 SMD parts and an annoying way to program the chip using pogo pins ( of which you needed to make a custom adapter for, AND the you still had to solder on wires anyway. I think in future the PCB should be redesigned to use normal pins for programming as there is actually enough space.

Programming

This was buy far the worst part of the project, the github had very little detail on how to actually program these chips and to get the 12mhz internal clock signal calibrated correctly. I did ask some questions on the github but ended up writing my own instructions.

STEP 1: Connect the Programmer
Make sure your programmer is wired to the ATmega328PB correctly:
MISO → MISO (pin 18)
MOSI → MOSI (pin 17)
SCK → SCK (pin 19)
RESET → RESET (pin 1)
VCC → VCC (pin 7 or 20)
GND → GND (pin 8 or 22)

STEP 2: Check Current Fuse Settings
Open your terminal and run:

avrdude.exe -C”avrdude.conf” -v -patmega328pb -cusbasp -U lfuse:r:-:i -U hfuse:r:-:i -U efuse:r:-:i:i

You’ll get something like:
lfuse: 0x62
hfuse: 0xD9

STEP 3: Calculate New LFUSE with CKOUT Enabled
https://eleccelerator.com/fusecalc/fusecalc.php?chip=atmega328p

That becomes: 0x22

STEP 4: Program the New LFUSE
Run:

avrdude.exe -C”avrdude.conf” -v -patmega328pb -cusbasp -U lfuse:w:0x22:m
Now CKOUT is enabled. The system clock will appear on PB0 (pin 14).

STEP 5: Measure the Clock Output
Connect a frequency counter or oscilloscope probe to PB0 and GND.

You should see a signal close to 12 MHz.
If not exactly 12 MHz, that’s expected — the internal oscillator needs calibration.

STEP 6: Calibrate the Internal Oscillator (OSCCAL)
In your firmware:
Use a loop that outputs a square wave (e.g., toggle a pin).
Adjust the OSCCAL register value (0x00 to 0xFF) until the frequency on PB0 is as close to 12 MHz as possible.

STEP 7: Compile with Atmel Studio 7
Import ps3-charger.c into Atmel Studio and compile to a hex file.
You should enter the clock signal into the source code from earlier

STEP 8: Flash to ATmega328PB
Connect programmer (e.g., USBasp), and flash the new file, for example:

avrdude.exe -C”avrdude.conf” -v -patmega328pb -cusbasp -U flash:w:ps3charger.hex

avrdude -c usbasp -p m328pb -U flash:w:PS3-Charger-C7-250.hex

STEP 9: (Optional) Restore LFUSE to Disable CKOUT
Once calibrated, you can turn off CKOUT to regain use of PB0.
If your original lfuse was 0x62, restore it:

avrdude -c usbasp -p m328pb -U lfuse:w:0x62:m

Files can be found here

Testing them out

After programming them finally, I found that it didnt work very well with just 1 controller plugged in, the timing or capacitance on the USB lines must not be right, 2 controllers always started charging immediately. There is some notes in the schematic to fix that for a new revision they never got around to I guess.

Dualsense Controller Hall-effect Upgrade

Somehow I ended up with a bunch of faulty Dualsense controllers and then a few mates wanted theirs fixed as well, so I ordered up a bunch of them to do them all at once.

Removing and reinstalling

Tearing down the controllers was pretty easy, although I did realise that there is 2 different versions of dual sense controllers already. It is always easier to remove the old sticks with new solder, then a desoldering gun, then hot air out the last of it and they just drop out. If you have good hot air, you could probably do it all in once step.

I got the replacement hall effect sticks from AliExpress, https://www.aliexpress.com/item/1005007688806322.html?spm=a2g0o.order_list.order_list_main.186.785e1802SoJOqZ

The only thing you have to do after you replace them is recalibrate the sticks afterwards. I used https://dualshock-tools.github.io/

Ikea Besta Cooling Fans

This is just a quick little project to put some exhaust cooling fans in my Ikea TV cabinet so the PS5 doesn’t overheat and die. 

Gallery

Just a few photos of the finished product. Its a mashup of 2 STL files, a 2x120mm fan mount and 120mm exhaust funnels. I am using USB to 12V fan adapters.

https://www.thingiverse.com/thing:1745860
https://www.printables.com/model/525851-adjustable-bracket-for-a-120mm-fan
https://www.aliexpress.com/item/1005007600112166.html?spm=a2g0o.order_list.order_list_main.251.785e1802SoJOqZ