Back in 1988, at my 35th birthday party, the cops came twice to tell me to lower my stereo volume.
I have hearing loss from a DnB show from 20 years ago. Tinnitus is real, kids!
In high school we had a block party. The "real" party was in my back yard, where I had my enormous 15" 3-ways set up. You could hear them over a mile away, over the traffic, train, and factory noises.
No cops were called. Yes I'm deaf as a stone today.
This is interesting, because I had terrible tinnitus and it's much better now after getting my diabetes under control and losing 60 pounds.
I never discussed it with my doctor. I will bring that up.
I can do you one better Eddie...
This year's July 4th holiday, us neighbors got together for a cookout in my neighbor's yard, and they begged me to haul out my home-made custom jukebox that's been sitting since 2015 in my garage.
Thankfully, I have casters on the bottom.
200 watts, 4 10" woofers, 4 tweeters.
one "loudness" test that day had the music echoing off buildings down the street, but we kept it at reasonable levels for consideration of the neighbor's ears.
Back in 81 I think it was - I was having a b-day party and the cops came 3 or 4 times. This was back before I had a real sound system. 20 watts per channel, TUBES, a couple of Varco 8’s. We finally had it down about as loud as a clock radio, and the cop said he could still hear it at the fence, and that it was too loud. At that point, I disconnected the amp entirely and got out my disco light system. We knew who the complainer was so I pointed the rig at her windows and ran it all night with no music. No audible music anyway.
Want flashing lights? We’ll give you some flashing lights!
GE Microwave oven. The boss holding one side of the door opener "paddle" snapped off. I replace it with a piece of wood, with a hole in it to accept the plastic pin of that one side of the paddle.
I can only get so close with just my hands and a straight edge ruler. I dont have a milling machine with cranked x-y table. Couldnt hold the tolerance necessary for the door closed microswitch (paddle pushing too hard against the latch, so the switch wouldnt close), nor the door open kill microswitch (paddle not pushing hard enough...) Decided to have another go tomorrow.
Wife suggested that I simply flip the wood piece; maybe the asymmetry of my work would do it. It did! Door mechanism operates, microswitches close when the door closes.
Now as an ode to whomever designed that boss - which probably takes more pounding from the user than any other part - your design stinks. Did you realize the comparitively nicely constructed chassis, cover, capacitor, microwave tube, fan, PC board, connectors, keypad, turntable, AC line filter, light bulb, fuse - the envelope someone actually bothers to place inside the unit containing schematic and service information - it ALL goes into the trash because you cut that bit down to - literally - a 1/16" thick molded plate support structure, when it snaps off that is, rendering the oven useless.
Amazing the single point failure potential some costly and otherwise well done product rides upon. Next microwave is going to be one with a handle on the door - I've always been wary of these push-button openers.
I can only get so close with just my hands and a straight edge ruler. I dont have a milling machine with cranked x-y table. Couldnt hold the tolerance necessary for the door closed microswitch (paddle pushing too hard against the latch, so the switch wouldnt close), nor the door open kill microswitch (paddle not pushing hard enough...) Decided to have another go tomorrow.
Wife suggested that I simply flip the wood piece; maybe the asymmetry of my work would do it. It did! Door mechanism operates, microswitches close when the door closes.
Now as an ode to whomever designed that boss - which probably takes more pounding from the user than any other part - your design stinks. Did you realize the comparitively nicely constructed chassis, cover, capacitor, microwave tube, fan, PC board, connectors, keypad, turntable, AC line filter, light bulb, fuse - the envelope someone actually bothers to place inside the unit containing schematic and service information - it ALL goes into the trash because you cut that bit down to - literally - a 1/16" thick molded plate support structure, when it snaps off that is, rendering the oven useless.
Amazing the single point failure potential some costly and otherwise well done product rides upon. Next microwave is going to be one with a handle on the door - I've always been wary of these push-button openers.
A USB PC oscilloscope I designed.
It has two trimmers for setting channel zero's on display.
One worked ok the other didnt.
I found 3v3 on output from op amp.
Traced it back to input and input had 3v3 on it.
Checked resistor values around op amp and they were fine.
Removed clipping diode to 3v3 rail anjd it worked ok.
So duff 1n4148 diode. It was in right way around according to marking.
It has two trimmers for setting channel zero's on display.
One worked ok the other didnt.
I found 3v3 on output from op amp.
Traced it back to input and input had 3v3 on it.
Checked resistor values around op amp and they were fine.
Removed clipping diode to 3v3 rail anjd it worked ok.
So duff 1n4148 diode. It was in right way around according to marking.
Me, not being obsessed or anything, but when I build something, I test each component before it gets installed.
Because on rare occasions, there is a defective or out-of-range component to complicate matters.
Some simple testing jigs are nice to have, or build some.
I remember there was a tech in our lab - older fellow - who would get up from his seat, walk over to the next isle, and put whatever passive component up against the disc-terminals of the HP4262A LCR meter. I asked him why he did that. Said he got burned too many times; the effort to debug a mislabeled component far outweighed his short walk.
Hey, I've had things like capacitors being "off value" too, one reading 470uF but labeled 1000uF, etc etc.
And a few resistors too.
And..... some leaky diodes.
The time to test everything would make the items too expensive to sell.
Its rare to find a wrong or bad component. Twice in 10 years.
The faults are usually either solder short, a missed solder joint or even a component missing because it was out of stock.
That really depends on the scale of it... And the complexity of the part.
They test CPUs before they sell them
The problem isn't if it works or not, it's usually just out of spec enough to cause "Gremlins"...
Example, the 1µF cap tests as 100nF so there's no bass in that channel, or a different than expected value that makes a phase shift that causes motorboating in the gNFB loop etc.
They test CPUs before they sell them
The problem isn't if it works or not, it's usually just out of spec enough to cause "Gremlins"...
Example, the 1µF cap tests as 100nF so there's no bass in that channel, or a different than expected value that makes a phase shift that causes motorboating in the gNFB loop etc.
I have only had one design work out of spec.
I designed a USB audio mixer.
Built it up and 1VAC of hum on output !
Everything checked out ok.
I eventually tracked it down to smoothing cap charging impulses modulating the ground line.
This was being amplified and reached 1VAC even with shorted inputs.
So reworked the pcb keeping power supply separate.
Audio and power connections only connected once at the edge connector.
PCB came back and this time no hum at all.
That's a good result
Today I didn't repair but modified an amp here to use the new VA/PI/DR boards that can use LED for biasing the first stage instead of RC.
Needed 1.9V to replace what was being dropped in the 330R upper cathode resistor (lower is 68R and junction to gNFB) and I thought "It's probably yellow" and it was... 1.94V
Today I didn't repair but modified an amp here to use the new VA/PI/DR boards that can use LED for biasing the first stage instead of RC.
Needed 1.9V to replace what was being dropped in the 330R upper cathode resistor (lower is 68R and junction to gNFB) and I thought "It's probably yellow" and it was... 1.94V