Recent Posts

1

Repair / Re: Need Help Identifying Component with ID '5ACRPT' SOT-26

« Last post by fzabkar on Today at 04:17:01 am »

5AC = NCP1251ASN100T1G

http://markingcodes.com/search/c/5ac
https://www.onsemi.com/pdf/datasheet/ncp1251-d.pdf (datasheet)
https://help-master.com.ua/ua/p583800134-mikroshema-ncp1251asn100t1g-tsop.html (photo)

2

Mechanical & Automation Engineering / Re: low temperature coolants?

« Last post by coppercone2 on Today at 04:13:58 am »

try ethylene glycol 100% ( ie car antifreeze ) they used it for cooling in WW2 aircraft, should be cheap enough and readily available for you to test

i avoided that one for the same reason as methanol, i.e. when a hose disconnects and you get popped by a cobra

3

Beginners / Re: Can a Powerbank be used to start a car?

« Last post by JustMeHere on Today at 04:06:51 am »

The car's alternator generates more than enough electricity for the car when the engine is running. The battery is only needed to start the engine and if the car can be stated with the little power bank why do they put such a large battery in the car?

Lead Acid batteries are relatively cheap.  More tolerant.  And don't explode as easily as lithium.  The weight makes little difference to a car.


FWIW....there are starter packs that use lithium batteries that start car from a very dead battery.  No, precharging before attempting to start needed.  For a small engine, they are the size of a flat tissue box.

4

General Technical Chat / Re: 78L05 placed in reverse?

« Last post by Brumby on Today at 04:05:46 am »

Doesn’t  everyone KNOW that a regulator installed backwards, becomes an UNREGULATOR. 

It was my impression that they became a DEregulator.

Apparently they have been utilised in some government applications - with very mixed results.

5

Repair / Re: Roland E-35 keyboard with temporary noise/hum

« Last post by Vertamps on Today at 03:55:12 am »

Its over 30 years old, caps are generally great for 15 years and really go downhill after 20 depending on the quality.
Go with Nichicon and Chemi-Con and its good for another 30 years, and there are so few caps the order is going be
$30 including shipping from Digikey or Mouser.
I always replace capacitors on most music gear older than 2003.
*Check you have the correct DC voltages from the power supply.
-William

6

General Technical Chat / Re: $5 scrap pcb haul ($222) worth of ICs

« Last post by Vertamps on Today at 03:46:37 am »

I could see myself hooking up some clear tubing to a pen shell. I think i can also revere the airflow on my machine.

7

General Technical Chat / Re: Does anyone make good SSDs any more?

« Last post by IanB on Today at 03:46:09 am »

Wow, is this thread so old? I just scrolled up and realized I've posted in it before. Here was me thinking it was a new thread.

8

Test Equipment / Re: Tek 2465 Horizontal Sweep Issue

« Last post by kellymcdonald78 on Today at 03:41:49 am »

I’ll take another look, been out of town recently. XY mode seems to work, and I’ll check the voltage on pin 18 to see what I see.

9

Metrology / Re: Is anyone into quantum technologies and quantum metrology?

« Last post by Harfner on Today at 03:40:24 am »

Would be interesting to have such a laser handy, run it at a low power, at a "constant" temperature and current and use it as a voltage source (like we do sometimes with an LED).

You mean, like an LED is sometimes used as sort-of-zener diode? Would a quantum dot laser have good voltage stability if used that way?

10

Beginners / Re: 5V buck converter debugging

« Last post by davegravy on Today at 03:37:06 am »

Is there some way I can bring this board up more incrementally?

E.g.

1) solder just the IC and C5, apply power, check for overcurrent/overheating, check for nominal VCC
2) solder C6, apply power, check for overcurrent, check for ? switching waveform on SW1/2/3
3) solder inductor and remaining components, check for overcurrent

Or is the issue almost certainly not going to present itself until the last step when there's inductor current?