$7 Smart Component Tester (LCR-T4 M328)

**tsbrownie** · Dec 19, 2019, 06:04 PM

If you deal with electronics for work or hobby, this is something to have! They are cheap $6-$7, but come with no instructions.

Got one of those smart component testers: resistors, capacitors, transistors, MOSFETs, diodes, ... Testing the tester.

WARNING: There is always a danger of shock, fire and electrocution when working with electricity. Capacitors of high voltage can kill if mishandled.

**mklotz** · Dec 20, 2019, 10:41 AM

I have to get one of those! I have a huge stockpile of components salvaged from old equipment and passed to me by folks retiring from the hobby. Identifying and testing it to select what I need is an eye-watering task.

I don't like to deal with Ebay or Bangood and the other Chinese-direct shippers but I see that the unit is available from Amazon...

https://www.amazon.com/Multifunction...J6JE19EAC96R9G

for $ 15.50 so it's on my shopping list.

**tsbrownie** · Dec 20, 2019, 08:34 PM

FYI: There is another style that has a digital selector. This one in this video is faster and easier. The selector type has calibration (and a basic freq gen, and freq counter). Either and both are better than doing lookups or using scopes, freq gens and standard parts to find values.

**baja** · Dec 21, 2019, 06:57 AM

Originally Posted by mklotz

I have to get one of those! I have a huge stockpile of components salvaged from old equipment and passed to me by folks retiring from the hobby. Identifying and testing it to select what I need is an eye-watering task.

I don't like to deal with Ebay or Bangood and the other Chinese-direct shippers but I see that the unit is available from Amazon...

https://www.amazon.com/Multifunction...J6JE19EAC96R9G

for $ 15.50 so it's on my shopping list.

Would that unit be able to diagnose a digital clock? I have a clock that came out of an old Marlboro advertising sign from a Circle K store in the mid 80`s that I set in a brass housing. It worked for years and years and one day started blinking like the power had shut down. Took it to a guy I know that fixes electronics and he had it for a couple months and it didn`t malfunction. I brought it home and found a loose connection in the cord which I repaired and it worked fine for a couple more months and the same thing. I can plug it in and it will run for a while and back to the same old, same old. I want to repair it because it`s the only clock I found that I can see at night with my glasses off, lol. Unless I spend big money on a new one.

**metric_taper** · Dec 21, 2019, 12:10 PM

Originally Posted by baja

Would that unit be able to diagnose a digital clock? I have a clock that came out of an old Marlboro advertising sign from a Circle K store in the mid 80`s that I set in a brass housing. It worked for years and years and one day started blinking like the power had shut down. Took it to a guy I know that fixes electronics and he had it for a couple months and it didn`t malfunction. I brought it home and found a loose connection in the cord which I repaired and it worked fine for a couple more months and the same thing. I can plug it in and it will run for a while and back to the same old, same old. I want to repair it because it`s the only clock I found that I can see at night with my glasses off, lol. Unless I spend big money on a new one.

No, it will test components that are removed from the circuit. Sounds like it is a power supply problem. I'm guessing this clock uses 5VDC logic. You can either figure out what is wrong with the supply, or replace it with a AC mains to low volt supply brick. Does the printed wiring board have any silk screen legends that indicate voltage? I don't know what your electronic skills are.

They do make a model of this, that has a boost supply that can test Zener diodes to 30v. This is what I purchased last year off eBay (search for "LCR TC1", you can find a USA seller if desired).

**baja** · Dec 22, 2019, 06:09 AM

Originally Posted by metric_taper

No, it will test components that are removed from the circuit. Sounds like it is a power supply problem. I'm guessing this clock uses 5VDC logic. You can either figure out what is wrong with the supply, or replace it with a AC mains to low volt supply brick. Does the printed wiring board have any silk screen legends that indicate voltage? I don't know what your electronic skills are.

They do make a model of this, that has a boost supply that can test Zener diodes to 30v. This is what I purchased last year off eBay (search for "LCR TC1", you can find a USA seller if desired).

Yeah, I remember from prior experience about removing the components to test them. I have minimum-t0-moderate electronic skills. There is no legend on it indicating voltage but I can remove it from the circuit and test the voltage and see what it is. The circuit board indicates it`s made in Hong Kong and has "0" jewels, lol. Thanks!

**metric_taper** · Dec 23, 2019, 07:19 PM

Originally Posted by baja

Yeah, I remember from prior experience about removing the components to test them. I have minimum-t0-moderate electronic skills. There is no legend on it indicating voltage but I can remove it from the circuit and test the voltage and see what it is. The circuit board indicates it`s made in Hong Kong and has "0" jewels, lol. Thanks!

Posting a photo would be helpful to see what the power supply (an analog circuit) and the digital clock circuits look like. I'm guessing it uses one IC that has the time clock, and the LED drivers. Can't help without seeing it.

**mklotz** · Jan 5, 2020, 10:30 AM

My tester arrived from Amazon a few days ago. Assembly was straightforward though one end of the plastic case won't fit without putting a lot of stress on the display cable. I solved that problem by not installing that part; doesn't affect performance and provides better ventilation of the electronics, though they certainly don't need it.

If you're an electronics dabbler this thing is just downright KEWL.

I pulled what I thought was a 100 pf cap out of my collection, plugged it in, and discovered it was a mini inductor. I have a lot of reclaimed components and this sort of misclassification is bound to happen but the tester will set me straight.

It produced believable values on a host of other components I tried. I had a few precision resistors so was able to test accuracy a bit and it was spot on on those.

I love it.