
My Commentary and Technical help
From BobDavis321
Tuesday, September 23, 2025
I am building a new deck.

Monday, September 8, 2025
Build Your Own LED Wall
Most P6 panels can be connected together by metal brackets that have holes on 1 inch centers and are found at most hardware stores. P4 and P5 panels use 3D printed junctions and 3/4 by 3/4 aluminum rails for the outside edges. I also have a mounting adapter for 5A-75B receiver cards that can control up to 8 strings of LED panels on thingiverse.This is a schematic of a typical setup. The 5A-75B can only control strings of 6 panels with the default lessings.
Here are two pictures of some assembled LED walls. The second does not have the top and bottom aluminum rails installed and the vertical rails were moved to the middle of the panels so they would match the hanging loops spacing.
Thursday, September 4, 2025
Mini-Split Line Cover Problems
I have now installed three mini-split heat pumps. I would only recommend the MrCool ones as the flared line sets seem to always leak. One of the issues is in covering the line sets. Some people use the plastic eves, and I have done that as well on an existing HVAC installation. This one installation took two of the line cover kits at $39 each, and then I was still short one straight coupler. So I designed my own couplers and 3D printed them.
Friday, August 15, 2025
I finally got a Zero Turn Mower a Z Force S 46
I bought my first Zero Turn Mower, its a Cub Cadet Z Force S 46 for $350. Boy was I in for an education! The mower only had power to one rear tire. I decided to change the trabnsmission fluid but quickly discovered there is no drain hole! So after watching many Youtube videos I decided to add my own drain holes. I chose a 1/4-20 by 1/2 inch bolt, with a metal washer and a rubber washer to make it watertight. I drilled a small hole then the hole size for the tap then tapped the holes. Changing the fluid did not fix the problem!
After watching many more videos I decided to see it the lever was being pulled to tell the transmission to move. It worked on one side but not the other. I chased the issue to a broken plastic part costing about $16.
Wednesday, May 21, 2025
How to repair LED matrix panels.
A few years ago I had two P3 LED panels with missing LED's in the corners due to being beaten up in shipping. Recently it happened again, this time three P5 LED panels had missing LED's from shipping abuse. In another case I bought 18 P6 panels that were likely bad before they were shipped. Every panel had bad LED's, some had as many as 30 LED's that were not working out of the 1024 on the panels. At first I repaired them to where 1-5 LED's were still out, but then with a better soldering iron tip I was able to get them to 100% working.
I want to show you how to repair minor problems with LED matrix panels. Usually it is a corner LED that is loose or missing. You can buy reels of 100 LED's for about $6. In the P3 and P5 panels they were 2121 LED's. The P6 panels had 3535 LED's.
First remove the almost invisible screws near the missing LED. Then lift the panel screen and make two small cuts in the screen as can be seen in the next picture. Remove the cut out piece. Set the screen back down. Clean up the solder pads, leave some solder on them.
Wednesday, May 7, 2025
Signs, Signs, Everywhere Signs!
I have just finished my latest book "LED Sign Projects". I am not happy with the cover. Besides being off center its kind of redundant. LOL. Also they used to add a page saying it is a proof. But if you were happy with it you could remove that page and sell it. Now they have "Not for Resale" on the cover! The proof costs about the same as buying one so why do that to it!?!?
Here are some of my other LED signs from the back side. This is similar to the one shown above. Note that the panel joiners are all 3D printed. I tried 3D printing the edges but they broke too easily so I use 3/4 inch L aluminum extrusions found at most hardware stores.
This is a water resistant version featureing 4x5 or the 32x32 pixel P6 LED panels.
Monday, May 5, 2025
Using LED strips to light up a Street sign instead of fluorescent bulbs
A couple of years ago I replaced the non-working five foot fluorescent bulbs in our church street sign with LED's. However the horizontal strips were visable and became annoying. So I came up with the idea of using edge lighting. The LED strips would be on a metal surface so they would be less likely to overheat and burn out.
I had some 130 per Meter or 36 per foot 2835 SMD LED strips. They were 10 Meters or 394 inches or 32.8 Feet in length. They are soft white and run off 12 Volts. The total power is 90 watts per 10 meters length. I used two of these strips for four laps around the inside of the sign. I think if I was to buy them I would get bright white LED's instead.
Monday, March 31, 2025
We had to dig up the church well
The pump quit in the church well so we had to dig it up. When we tried to pull it we could see somthing on the pitless adapter. We tapped it with a long stick and discovered it was a rock and now it was further down in the well. No amount of pounding or pulling would loosen the pitless connector. So we had to did up the well.
Waveshare Zero to Pi3 Review
I recently purchased a Waveshare Zero to Pi3 adapter. I had a couple of Pi zero's laying around not being used because I had to look up the HDMI and USB adapters in order to use them. One Zero was even so old that it did not have any built in network ability. I had to use USB memory sticks to add programs to it.
Friday, March 14, 2025
Mackie Thump TH-15A Powered speaker Repair
I was asked to repair a Mackie Thump TH-15A Powered speaker by a friend. It powered on and everything looked good but there was no sound coming out. I checked the speakers and the power supplies but everything was just fine. However, the computer board was getting really hot. It had 3.3 volts coming into a voltage regulator but only .5 volts coming out. I tried easter egging the capicitors and it turned out to be the tiny little .1 uF capacitor that was shorting out the power supply. The correct output is 1.2 volts.
This is what the guts look like, we are going to zero in on the logic board.