The AM Forum

The IT-28 stopped working for electrolytic caps.  There is no deflection of the magic eye, good cap or bad.  It works for others. Do any of you know what it's trying to do differently for electrolytic caps? I'm getting a headache trying to decipher the wafer diagram.

Also, is there something modern and reliable I could get that could replace it? It's such a staple on the work bench but I hate flaky test equipment. I'm baffled enough without the test equipment adding mystery.

I paid 30 bucks and bought a component analyzer from China to work on cataloging the 400 lbs of bulk parts I got for ten bucks.

Measures anything, even unknown components, and tells you what they are.  Mosfets, transistors, caps, etc.

The only thing I don't see working correctly is the L function.  It always wants to treat as a resistor.  As I have a VNA and AADE lc meter, not a big deal.

This also has an ESR meter built in, which has agreed really closely to published specs of known recent made electrolytics.


Identical item to 322393525803 on eBay.  Like I said, I spent 30 bucks.  I see them for 10, if you don't want a case.

So far  accuracy as published, compares favorably with the AADE, a VICHY meter as well as my 600 dollar fluke, and the vna.

And, it's usb rechargeable.

--Shane
KD6VXI

Another shameless plug for that component tester.

I bought a bag of 100 x MPF102.

Tried 4.  ALL BAD!

Bought some j310, worked perfect.  Stuffed the bad mpf devices into a corner of the bench.

Got the tester, said what the hell.... 

Turns out gate and source where reversed, and the fets still work pretty decently.  I've NO idea what they actually are, but that saved me from trashing 'counterfeit' devices.

--Shane
KD6VXI

Fixed! After barking up the wrong tree for awhile, I discovered a bad R in the switched voltage divider. 22K R30 had zoomed to 1.6M. It didn't matter much for paper caps but electrolytics are a horse of a different color.

Shane. Thanks for the tip. I may get one of those.

Got a link to this magic device?

http://m.ebay.com/itm/3-5-TFT-Transistor-Tester-Diode-Triode-Capacitance-Meter-LCR-ESR-NPN-MOSFET-US-/322393525803?nav=SEARCH

The downside, it only drops to 25 pf.

--Shane
KD6VXI

I'm glad you fixed the IT-28. Too often people give up on the older gear especially that which is not 'big name', when all they need is some TLC after the decades of time.