Electronics > Repair
1978 Ivie Electronics IE-30A Spectrum Analyzer and IE-17A Audio Analyzer Repair
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Smoky:
I do remember how the performance of the analyzer slowly faded over the course of a day or so of random use that maybe totaled 2 hours.

The new battery sets of both the Ni-Cad and Ni-MH that I tried slowly drained because the charging circuit did not work. So it was the original charge of the new batteries that was ever utilized and expended.

The service manual states a maximum of 1.5A of current for the analyzer's charging circuit.

I just tested the wall-wart open without a load. The voltage at my outlets at home is 121.9 VAC:

9.90VDC with 2.0mV ripple using my handheld DMM.

I think that if the battery is low or dead, the analyzer will display just the red power/charge LED when the wall-wart is plugged in but the analyzer will not operate.

Only when the red and green LED's or just the green LED is lit, will the analyzer operate.

It is a power hog!
GLouie:
We had an IE30 at work when these were new, with the pink/white noise generator. They were really whiz-bang at the time, but over the years lost favor due to expense and alternative measuring methods and devices. IIRC, Greg Mackie worked on a cheaper alternative for Audio Control that became popular due to much lower cost, although only Class 2 filters instead of Class 3.

Our IE30 lost favor and was seldom used for many years until it no longer held a charge. I rebuilt the battery pack a couple of times, IIRC was 4 NiCds smaller than sub-C, but with no one using it, moot point. Then we also had 2 failed LEDs.

It was still working when I retired last year, but I didn't keep my files of documentation. For sure it's a power hog, but it could certainly run continuously and charge the batteries with the big factory AC power pack attached. There was another smaller AC adapter for charging the IE-20 pink/white noise generator, but it had a sub-mini phone plug IIRC, so couldn't be confused with the coax power plug of the IE30.
Smoky:
With an 8 Ohm load on the output of the wall-wart, my DMM measured .980 Amps at 8.2 VDC:







floobydust:
Yeah that AC adapter has a high output voltage, you'd like 7.0V max. at light loads (4 cells 1.56V each and the diode drop) and maybe 6V at high load I think. I wonder if it roasted CR10.

I would troubleshoot the charger and get it working before considering any modifications to it.
There's not much between the charger jack and the battery other than interconnects, diode CR10, and the relay, resistor R21.

With battery packs, if the (+) terminal ever touches a (grounded) metal chassis it can melt a ground trace/connection so also look for an open ground.

It doesn't have a low battery detect that I can see. Nothing to warn or shut it down when battery voltage is low. The charger red LED indicates high-rate charging, the green LED indicates slow-rate charging because the battery is hot or the charge timer has expired.
Smoky:
Exactly right. There's nothing to do until the wall-wart is squared-away.

I have a bunch of Triad Magnetics transformers that I bought on sale (10, 12, 16, 20, and 24 volt types). They would all easily fit inside the original wall-wart case with plenty of room to spare for more components. All of the transformers have dual secondaries. I'm using a 2W01MG 100v 2A bridge rectifier (w/1.1v drop) and a Nichicon HE 2200uf/35v capacitor to test their outputs under an 8 Ohm load.

I set a FS12-1600-C2 transformer up to test and I put the datasheet at the end of this post. Its secondaries are 6.3V at 1.6A each. Combined, that would be 3.2A. Well, since the transformers are also based on 115 VAC, the transformer came in a little high. Maybe a bridge rectifier with a higher voltage drop might work :-//

I measured 7.65 VDC at .933 Amps:





On a side note, and what bums me out, in the top portion of the bottom picture, you can see a small transformer attached to a cap. That little 10v transformer with dual 5v secondaries can deliver 1.2A combined but it measured ~5.5 VDC under test :-\ You could've put three of those inside of the original wall-wart case!
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