What is on your workbench right now?

[Sal1950]

@venquessa. I have worked extensively with 12V high current batteries like the battery you have on your floor in the house. I've personally witnesses maybe a dozen explosions caused by lead acid batteries. The explosions where in a battery shop that I used to manage and several where in a huge industrial building and so the roof, walls and windows where never damaged but it scared the heck out of the staff. I suggest you get that battery out of the house to avoid some sort of fire hazard or explosion potential. It's really dangerous.

Absolutely. those gases can built up under that table and one spark, BANG
"During operation and charging, lead acid batteries produce hydrogen and oxygen which occupies the headspace in a battery above the electrolyte. If such gasses are not vented correctly or are exposed to a source of ignition, battery explosion can occur."

 

[Doodski]

Absolutely. those gases can built up under that table and one spark, BANG
"During operation and charging, lead acid batteries produce hydrogen and oxygen which occupies the headspace in a battery above the electrolyte. If such gasses are not vented correctly or are exposed to a source of ignition, battery explosion can occur."

O, YeaH!.. lol. I've seen a SLA battery split open and chunks laying about after a good bOOMski. When I worked the battery shop manager job we used to cause lotsa small explosions and that was with the back overhead door open, venting the shop and we still had them. Nasty stuff and it eats most any fabric other than polyester.

 

[venquessa]

Thanks. Noted. It's a 100Ah sealed lead acid rated for 900CCA.

The only way for pure hydrogen or oxygen to get out is if the seal is broken. That would require enough current to boil the water and over pressure the battery (entirely possibly in a real world scenario). That would occur if you are pushing very high current or very high voltage across it.

The reality of lead acids and all batteries is using them within spec and based upon their manufacturer's limits... or in this case dividing most of them by an order or magntude before it's an old, tired lead acid.

This particular lead acid still shows a "green" light on it's sight glass.

990Amps, for 5 seconds. I'm pulling 3Amps and it can't maintain 12.1V. It's dead. I know this. Charging with a max of 5amps. I am using trusted electronics bench supplies and multimeters to verify voltages/currents.

When you are using a bench supply/load in both directions charge/discharge you control all of it on both sides.

If you think the lead acid is a concern, wait till you see the lithium replacement. Y'all have a panic attack! It would probably melt this old lead acid's heart.

 

[reysero]

Too much. In the cardboard box is the DSP (so I can protect it from me being an idiot). It has it's new power supply (in the unshrunk shrink tube) as the onPCB regulator died. Along side the UI dev bed. Which as you can see from the random gibberish "volume" value is coming along really well (sarc).

On the left is my complete mess of 12V/5V USB and DC wiring running off that little power supply (coming from the solar LFP 12V garage system)... and the 100Ah Marine lead acid "buffer battery" on the floor... which is about to be capacity tested this weekend with the colourful little gizmo. Out of shot the internet router and network switch are running off said lead acid. It itself is a temp surrogate for a new "Audio lab battery", a 6S LiFePO4 battery, which I will multi-tap for a range of voltages including -10+10.

My little blue 1.5 Watt headphone amp glowing nicely.

(Yes, that feed does come in through the wall via a 6mm cable ... and I tap it with croc clips. It's 12V FFS. It's fused at 15A, if the cat shorts it, the fuse will blow.)

EDIT: ON protecting the thing from "me". This week I am healing a nasty blister a whole in my pocket and feeling dumb. I set said new power supply on top of the MCU board. It was powered off of course. Not that dumb. Until later on, when I switch it on and didn't immediately play any music. So I didn't notice it was shorted. When I did notice I lifted the PSU board off the MCU and immediately dropped it because of how hot it was. Being even more dumb I then put my finger on the MCU itself to see how hot it was. It now bears the tattoo of my fingerprint and I lost about 1mm of the skin off my finger . I figure it was just below glowing orange 300+C. £40 replacement.... already in stock.
Not two nights later I put my multimeter into the mains outlet of an inverter on the wrong setting and fried it. £100 replacement. Meter "should" have survived it, but due to design/wear and tear it failed to.
View attachment 277318

EDIT: The MCU in it's shorted state was consuming 1.6A at 12V. Most of that heat seems to have been centred in the exact point I touched.

This is a good idea about tattoo.

 

[Ricardus]

On my bench right now is a vacuum tube spring reverb unit that I am building for a friend.

 

[thecheapseats]

must be UPS repair month... rebuilding one of four apc ups units that are hanging around here - it was time at appx 15 -20 years old... a few bad caps and some out of spec components... don't make 'em like this anymore...

 

[Sokel]

I'm finally getting around to replacing the innards of my main music server box that got fried by a lightning strike last fall..
Not a brand new board but I got a friend that's a gamer and upgrades his box every few years. Couldn't pass by the deal.
I paid the shipping only for the board and i7 cpu. I've got it all up and running and in the system now, smoking fast with
my Linux OS, Delivers 4k Video w/Atmos sound without a blink. Yippee.

View attachment 276890

Coolermaster rocks!
One thing only,you have put PSU upside down,just flip it the other way,it even has it's own dust cover underneath.

 

[Steven Holt]

As soon as I get off here I going to start on a pair of Utah VERY LARGE standmount speakers, 3 way 12 in. woofer full horn mid some kind of metal ring tweeter. The crossover is a joke, some kind of resistor. I hardly know where to start, but PartsExpress is going to get a lot of business from me, I suspect.

 

[Sal1950]

Coolermaster rocks!
One thing only,you have put PSU upside down,just flip it the other way,it even has it's own dust cover underneath.

Yea, I know. I felt it actually got better air movement and ran cooler that way.
It's been running in that CoolerMaster case for 15+ years like that. LOL
I was thinking about replacing it when I put in the motherboard and all the rest for a modern one with modular cables
but I was too cheap right now, maybe down the road. It's never given me a lick of trouble since I bought it in 2008.
The donated mother-board is around 8 years old too so they feel at home together. LOL

I love that CoolerMaster case, it's a bit of a size monster but has the room to do about anything you'd ever want.
It has the removable cartridges to hold 6 spinner drives or 12 SSD's. plus 5 more front accessible optical or
whatever drives, 5 cooling fans, lots more. Currently holding 11TB of SSD's, It operates as the centerpiece for my
music-video server and all around day to day computing needs.
Running PCLinuxOS Linux operating system, it covers just about all my needs.
Thanks for your input.

 

[Sokel]

Yea, I know. I felt it actually got better air movement and ran cooler that way.
It's been running in that CoolerMaster case for 15+ years like that. LOL
I was thinking about replacing it when I put in the motherboard and all the rest for a modern one with modular cables
but I was too cheap right now, maybe down the road. It's never given me a lick of trouble since I bought it in 2008.
The donated mother-board is around 8 years old too so they feel at home together. LOL

I love that CoolerMaster case, it's a bit of a size monster but has the room to do about anything you'd ever want.
It has the removable cartridges to hold 6 spinner drives or 12 SSD's. plus 5 more front accessible optical or
whatever drives, 5 cooling fans, lots more. Currently holding 11TB of SSD's, It operates as the centerpiece for my
music-video server and all around day to day computing needs.
Running PCLinuxOS Linux operating system, it covers just about all my needs.
Thanks for your input.

I have the same in black,the quality is outstanding,these brushed aluminum panels with the sound absorption material were a killer feature.
I don't think I'll ever need another case.
As long as the PSU orientation it's all about sucking the GPU's hot air (the upper part of yours is the intake) which PSUs don't like a lot but as long as it works and passes the time test everything ok!

 

[Sal1950]

As long as the PSU orientation it's all about sucking the GPU's hot air (the upper part of yours is the intake) which PSUs don't like a lot but as long as it works and passes the time test everything ok!

GPU has dual fans which exhaust out the rear, don't think it's an issue.

 

[dfuller]

Lately:

Vox AC30C2, jack to main board connector came loose. Reseated, amp works great.
Ampeg BA115, missing a knob and needed a new power connector. Fixed, amp works great.

Vox AC15, in for a checkup.
Fender Hot Rod Deluxe, noisy. Probably caps and the usual Hot Rod Deluxe dropping resistor fun, haven't opened it up yet.

 

[Thomas_A]

Still working on my motor control board for the turntable with a new motor; not easy to understand the whole circuit, I have no formal education in electronics. Don't know if I need to change the motor current sensing resistor (10R) since the motor windings of the new motor have higher resistance, but I have increased the drive voltage from 25V to around 40V to be stable.

 

[Peterinvan]

Just installed Knowles “Brown” acoustic filter in my Shure SE535. These are about 2mm and need a magnifying glass and tweezers to install. I got the slight bass boost I was looking for.

 

[dfuller]

Lately:

Vox AC30C2, jack to main board connector came loose. Reseated, amp works great.
Ampeg BA115, missing a knob and needed a new power connector. Fixed, amp works great.

Vox AC15, in for a checkup.
Fender Hot Rod Deluxe, noisy. Probably caps and the usual Hot Rod Deluxe dropping resistor fun, haven't opened it up yet.

Opened that HRD today. The usual problems of ****** IC caps and burned boards from poorly thought out mounting of resistors and zener for the LV supply have shown up yet again...

 

[thecheapseats]

Opened that HRD today. The usual problems of ****** IC caps and burned boards from poorly thought out mounting of resistors and zener for the LV supply have shown up yet again...

Leo Fender's pride and joy... electric toy...

 

[dfuller]

Leo Fender's pride and joy... electric toy...

The worst part is the old Fenders - i.e., tweed through Drip Edge - are incredibly well built amps. These... aren't.

 

[pma]

Right now it is Audiophonics PRE-TC10 preamp with tone controls.

New unit, bad LM337, fixed.

Bad LM337:

Fixed:

 

[Sal1950]

New unit, bad LM337, fixed.

My hat goes off to you being able to solder on that tiny stuff.

 

[pma]

My hat goes off to you being able to solder on that tiny stuff.

This one was hopefully not so tiny as are the pins of SMD SOIC packages, however, I admit that my 68 years old eyes are not what they used to be .