1978 Ivie Electronics IE-30A Spectrum Analyzer and IE-17A Audio Analyzer Repair - Page 1
Forum section: electronics / repair

author: Smoky
author_rank: Frequent Contributor
timestamp: December 18, 2024, 02:44:09 am
content: Before I joined EEVblog, I did a repair of an Ivie Electronics IE-30A Spectrum Analyzer in 2018 on AntiqueRadios.com website:https://antiqueradios.com/forums//viewtopic.php?p=3000319I fumbled my way through it but found a short that kept one of the frequencies from displayingUnfortunately, the power supply section faded away soon after even though I replaced the large rechargeable batteries. At first I bought Ni-MH ones but soon realized that I could only use the original Ni-Cad types. I'm not sure if I caused more damage because of itWell, I packed the spectrum analyzer away for a future repair attempt.The IE-17A is an Audio Analyzer that bolts to the bottom of the Spectrum Analyzer.After reading its Users Manual, I found that it can send "snaphots" of graphs from the IE-30A when its connected to an oscilloscope! They even give examples of some. Extremely coolAnywho, this is one compact little instrument:Something that I was wondering about was, would it be possible to internally switch from a Ni-Cad charging circuit to a Ni-MH type? They mention that the demand for power is high when attaching the IE-17A. It would be nice to really beef-up the battery capacity.But, of course, I need to see if this thing can be brought back to life again first.I will attach all of the individual schematics, user's manuals, and calibration documents.

author: Smoky
author_rank: Frequent Contributor
timestamp: December 18, 2024, 02:51:17 am
content: Just to make it easier, here are the block diagram, power supply, wall wart, and board layout pages......and the User's Manual for the IE-17A is also attached as a PDF

author: Smoky
author_rank: Frequent Contributor
timestamp: December 18, 2024, 03:04:12 am
content: It's going to take a little time to get the analyzer back apart and laid-out on a bench.With parts being much smaller these days and PCB's able to be made cheaply, it would be something to make "new" replaceable boards where/if neededI have tons of pictures from 6years ago plus I'll be taking more.The IE-17A seemed to work like it should when it was stored but, at the time, I didn't know it could plot graphs and such so I never tried to hook it up to a scope.

author: floobydust
author_rank: Super Contributor
timestamp: December 18, 2024, 04:24:14 am
content: It's quite the piece of kit. Ifound itin dB Magazine circa 1977 and more. It would've changed the sound industry with portable real-time and ADC as well doing pink noise analysis I think.Do you have the schematic for the charger board 30P08? I'm a bit leery it seems to use battery temperature for end-of-charge to toggle a relay?I think you can match the old NiCd performance with NiMh 2,450mAh AA's with a mod to the charging voltage settings.

author: Smoky
author_rank: Frequent Contributor
timestamp: December 18, 2024, 04:42:55 am
content: Oops, Here's another copy with factory notes and a price list. There was also a modification/changes performed on these things early on it appears.

author: Smoky
author_rank: Frequent Contributor
timestamp: December 18, 2024, 05:03:19 am
content: Here's a full-size image of the 08 Charger Board schematic:I didn't realize that I had two user's manuals one with and one without schematics

author: floobydust
author_rank: Super Contributor
timestamp: December 18, 2024, 05:51:36 am
content: Fast charging (pretty much limited by what the AC adapter will put out into the battery pack minus a diode drop CR10) is around 1A. That terminates if the 1 hour timer expires or the batteries heat up, which causes the relay to pull in and adds R21 10R resistor is series to drop charging current down, to maybe the 300mA the schematic mentions.NiMh does not like constant charging at all, they seem to dry out and go high resistance. So if you left it charging overnight, I would think the batteries will have a short life. Especially if the original AC adapter is unregulated.I would mod a modern (regulated output) 9V 1A adapter to give 7.0VDC output and use that but I suspect the SMPS noise would be a problem, probably would add a lot of common-mode noise and make a mess with mic input noise.Change it to a 3 hour timer and upsize to 2,500mAh battery. Increase R21 greatly to say 100R for minimal constant (slow) charge current. Just some ideas.Q1, Q2 form a latch but not sure what it's for.

author: Smoky
author_rank: Frequent Contributor
timestamp: December 18, 2024, 10:25:21 pm
content: I took a picture of the label of the 6v Ivie wall-wart transformer. It appears to be a 2 Amp version dated 1986:I warmed the bottom cover of the wall-wart with my heat gun and it popped offA small PC board has one 4700uf 10v electrolytic and four PX1N5401 diodes.The stuff on the side of the capacitor is solder not a scrape.I plan to replace the capacitor and possibly the diodes. I can also test the wall-wart before and after the swap using a 4 Ohm load that I have. That seems to calculate ~1.5A of draw.The cord from the wall-wart is heavy duty but the plug that attaches to the analyzer I think needs replacing, or is usually the socket in the analyzer that's more often the culprit for a bad connection?Thanks FloobyDust!

author: Smoky
author_rank: Frequent Contributor
timestamp: December 18, 2024, 10:45:19 pm
content: I just noticed that looking at the schematic of the original wall-wart there is a diode and a resistor in series after the bridge rectifier diodes.The wall-wart that I have only has a smoothing capacitor after the bridge rectifier diodes.I imagine the current is being limited in the early original version.Should the wall-wart that I have be modified to limit current to 1 Amp before it enters the analyzer or is there a benefit to possibly utilizing the extra current?I checked the 4 new "C" sized Ni-Cad batteries I bought for the analyzer 6 years ago. They are 2800mAh each for a total of 11200mAh.

author: floobydust
author_rank: Super Contributor
timestamp: December 19, 2024, 03:20:42 am
content: I'm not clear if the analyzer can be powered by the AC adapter, or is it battery-powered only?First problem I see with that AC adapter is the lousy regulation, it might be 6V at 2A but at 1A or 0.5A or 0.1A, output voltage will skyrocket which makes it a battery killer. Once the battery is full charged, the voltage goes way above 7V I'll bet.Second problem is that missing resistor means it can charge at way over a 1A rate.Looking at NiMh Panasonic C 3,300mAh they list charging specs.HHR-300CH1,500mA for 2.4 hrs, or 300mA for 16 hrs. Low rate is 155mA 32 hrs, 100mA 48 hrs.Then I found "high-rate discharge type"BK310CHsimilar charging but no idea if a 1A drain is a lot.I'm not a battery expert. I would say you need to limit (fast) charging current keep it below 1.5A, and keep max. charge voltage to 1.50Vpc. The timer needs to be extended as well for the higher capacity cells.

author: Smoky
author_rank: Frequent Contributor
timestamp: December 19, 2024, 06:42:24 am
content: 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!

author: GLouie
author_rank: Regular Contributor
timestamp: December 19, 2024, 03:26:39 pm
content: 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.

author: Smoky
author_rank: Frequent Contributor
timestamp: December 19, 2024, 07:51:55 pm
content: With an 8 Ohm load on the output of the wall-wart, my DMM measured .980 Amps at 8.2 VDC:

author: floobydust
author_rank: Super Contributor
timestamp: December 19, 2024, 08:09:44 pm
content: 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.

author: Smoky
author_rank: Frequent Contributor
timestamp: December 19, 2024, 10:18:27 pm
content: 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 workI 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 testYou could've put three of those inside of the original wall-wart case!

author: Smoky
author_rank: Frequent Contributor
timestamp: December 20, 2024, 12:16:58 am
content: I went through my bin of diodes and found these:They are Vishay 31GF6 3A 600v single diodes and they have a Vf of 1.6v. That's .5v higher than the bridge rectifiers that I'm testing with now.If they wouldreallybring down the voltage that much, we'd be at 7.15 VDC.