Recent Posts

1

Beginners / Re: Basic AC/DC Din Rail Question

« Last post by ScottyB on Today at 07:46:04 pm »

P.S. Here's a small rack-mount control cabinet I finished recently, using Phoenix Contact terminal blocks. The left side of the rail has the 230V connections on PT 2,5-QUATTRO blocks, as well as the 24V DC power supply; on the right are the safety relay, relays, and then the low-voltage connections using PT 1,5-QUATTRO terminal blocks. The device this controls also has a tiny DIN rail in it with a few PT 1,5-QUATTRO on it. (In many positions, I don't need all 4 terminals of a PT...-QUATTRO terminal block, but it's cheaper and easier for me to just buy the 4-terminal QUATTRO versions in bulk than to buy small amounts of the 2- and 3-terminal versions, and the end covers for them, etc.)

Looks good. I’m not quite in that deep, but my understanding is infinitely better as of today. Thanks.

2

General Technical Chat / Re: Post a picture of a cat!

« Last post by TheSteve on Today at 07:45:41 pm »

Boomer often notes just how fast the bunnies are(and he has a leash on which doesn't help him).

3

Test Equipment / Re: HP 8566B - What to look for?

« Last post by W4PJB on Today at 07:45:30 pm »

Thanks again for your reply!

The first two digits are 31, so that should make my unit a '91 or later model. Great!

I will look into a better LCR/ESR meter for this. Never hurts to have one on the bench anyway. The DE-5000 seems to have a good following here for the money.

Also great info on the REF UNLOCK error. Unfortunately I was not able to keep it in warm-up long enough to see if it went away. YTO ULOCK did come up for a minute or so when I powered it up at the sellers house, but it quickly went away. It did not come on again when I powered it up at home, just REF UNLOCK. They got the SA from an estate sale, and are not electronics savvy, so I unfortunately have zero history on the unit.

Once I get an ESR meter I'll check all the caps in the RF section as well, hopefully that does the trick for the high band. I plan to replace the large caps in the power supply too, while I'm in there. I'll be sure to keep this thread updated as I progress, but now we're entering the waiting phase to get test kit, parts, and most importantly TIME to mess with it.

Thanks for the tip about Artek Media. The whole set of 5 manuals is only $15. I'll be placing that order right now!

4

Beginners / Re: Introduction & Help for a newbie on a simple SMPS

« Last post by Gyro on Today at 07:45:04 pm »

That was quick!

Yes, the output caps are certainly down a bit, but not to the extent that I would have expected a problem - they don't show any signs of venting due to over-dissipation.

The 10uF capacitor (presumably C8) does stick out like a sore thumb. It won't need to be anything special but 186R ESR is a definite fail, I would think this is the cause of the problem. Look for something 125'C rated if possible for a permanent replacement but anything will do for a test. ESR isn't going to be that critical.

The primary end of that SMPS must run hot.

5

Beginners / Re: Which DMM to use?

« Last post by BennoG on Today at 07:43:44 pm »

also if you make a mishap with your expensive 6 1/2 meter it is an expensive mishap, e.g.  measure mains AC while meter is in ohm range.
If you blow up a cheap 3.5 meter that does a lot less pain.
And this will happen to everybody some time, or multiple times.

Benno

6

Beginners / Re: Basic AC/DC Din Rail Question

« Last post by ScottyB on Today at 07:42:10 pm »

Thank you - all good advice.

I’m opting for the Wagos in a din rail carrier. Seems neat and simple.

I have had second thoughts about the power source, not liking the idea of live AC having a remote chance of being an issue, so going with a AC to DC brick, cut the connector off, then it’s DC everywhere.  I will tin the leads.

I do have it in an enclosure but @Kjelt got me thinking if someone was to poke around when I’m not here……not worth thinking about.

Such a helpful community and I’m definitely going to stick around.

7

Test Equipment / Re: $20 LCR ESR Transistor checker project

« Last post by madires on Today at 07:41:58 pm »

For those who see similar readings on silicon transistors on the k-firmware, which is incorrect (upper left corner). This is not a program error, but an incorrect measurement scheme. If we add inductance and capacitance to the scheme, highlighted in red SMD, we get correct readings for silicon transistors. For germanium transistors, measurements are shown - lower right corner.

Also recommended by the ATmega's datasheet, i.e. a small inductor plus cap for the ADC's power supply.

8

Beginners / Re: Basic AC/DC Din Rail Question

« Last post by tooki on Today at 07:41:38 pm »

P.S. Here's a small rack-mount control cabinet I finished recently, using Phoenix Contact terminal blocks. The left side of the rail has the 230V connections on PT 2,5-QUATTRO blocks, as well as the 24V DC power supply; on the right are the safety relay, relays, and then the low-voltage connections using PT 1,5-QUATTRO terminal blocks. The device this controls also has a tiny DIN rail in it with a few PT 1,5-QUATTRO on it. (In many positions, I don't need all 4 terminals of a PT...-QUATTRO terminal block, but it's cheaper and easier for me to just buy the 4-terminal QUATTRO versions in bulk than to buy small amounts of the 2- and 3-terminal versions, and the end covers for them, etc.)

9

Projects, Designs, and Technical Stuff / Re: Adjusting Fuel Gauge And Sender Resistances

« Last post by ThermallyFrigid on Today at 07:39:18 pm »

I think that's what I want to do......

Lower the resistance range of the Gauge ?

10

Test Equipment / Re: $20 LCR ESR Transistor checker project

« Last post by madires on Today at 07:37:58 pm »

UPDATE - no change to the voltage, I guess it's toast?

Yep, the LiPo battery needs to be replaced. I'd recommend also to add a small switch to the battery (to prevent draining it by the high quiescent current).