1965 Aiwa AR-145 12 Transistor Radio Issues
 

Hello everyone, this past Saturday I picked up from a local antique mall a 1965 Aiwa Model AR-145 12 Transistor AM/FM Radio that can run off of either 4 "C" batteries or AC Current.

Anyways this radio has very weak audio output (the volume has to be turned up almost full blast to be able to hear anything) and the tuner sensitivity/selectivity while its really good is really distorted even when the station is tuned in dead center, I figure its probably bad caps, but the problem is that the caps are hard to get to and unsolder from the circuit board, as I had already replaced the main filter cap which was a 500 MFD 6WVDC electrolytic and I had a heck of a time getting that cap unsoldered from the circuit board because they put too much solder on that cap and melted the (+) lead onto the board.

Anyways I would love to know a little more about this radio including if there's any service information for it out there and what kind of quality this radio would of been compared to say a similar model Zenith or Sony or RCA radio from the time period.

Thanks for your help.

This is the only AM-FM portable radio I have ever seen with the AM band extending down to 525 kHz. The standard AM broadcast band in North America begins at 550 kHz and ends at 1600 kHz. I don't know why this particular Aiwa radio goes down to 525 kHz on AM, unless the AM broadcast band actually starts there in Japan.

Your radio's weak audio may be caused by something as simple as weak batteries. Have you tried new ones? This is the very first thing I would check if I had a radio exhibiting very weak sound.

I wouldn't be too quick to suspect the capacitors until I changed the batteries. I am not by any means saying or implying the caps are not going bad (or have already, since the radio was made in 1965, 56 years ago), not having seen your set, but the batteries would be, again, the first things I would suspect in a radio with weak or no audio.

BTW, I have several Zenith AM and AM/FM radios that work and sound great for their ages. Zenith was one of the best, if not the best, manufacturers of radios (later televisions, of course) from their earliest sets until the last ones, the latter having been made just before the company was taken over by Gold Star. I hated to see that happen, as Zenith has always been my favorite brand of radio, stereo and television (I had several Zenith TVs years ago and truly hated to see the company leave Chicago). Zenith's radios, TVs and other products represented a level of quality we will, unfortunately, never see again.

To all of you who may still own one or more radios or TVs made by Zenith, I would say hold on to them as long as you can. The day Zenith left Chicago for Korea was truly the end of an era.

Yeah these Japanese sets almost always have bad caps. I have an AM only Aiwa from the same era. Same big slotted screw to get the back off. 3 C batteries only.

That would make sense to me, and it seems that from what you're describing Mr. Rye that if the AM only version of my radio uses only 3 C batteries, and mine which is AM and FM uses 6 C batteries then it stands to reason that each stage uses 4.5v each...:scratch2:

Run the radio a while & see if the audio driver or outputs are getting hot.
Often one will go leaky & cause symptoms like this.
Sams doesn't list this set so a manual will be a challenge.
The audio out area is pretty common design for most radios of this vintage.

73 Zeno:smoke:
LFOD !

Well I actually did a full alignment on this radio (or as full of one as I could do seeing as I had no service data on this radio) and the audio and reception perked up quite a bit in fact this radio's AM Band reception is just as hot as my Zenith Trans-Oceanic's AM Band reception! :thmbsp: :music:

The FM Band is still a little weak on the reception (two local Christian Stations that are very close to each other on the dial, one at 104.7 and one at 105.3) kind of crowd each other out.

Also the dial tracking is a little off as well, the lower end of the tuning dial range in the FM mode showed the pointer at almost off the dial (to the point of almost falling off the track that the pointer rides on) and there was still a half a turn of the tuning knob left before it reached the bottom of the tuning condenser's lower range (fully meshed) and on the upper end of the dial the pointer only reached to between the 105 and 108 marker on the dial and the tuning capacitor was at the top of its range.

So to attempt to fix that without having to mess with the oscillator adjustments (which are hard to get to in this set because of how they have the tuning capacitor situated in this radio) I loosened the set screws holding the flywheel to the tuning capacitor and moved the flywheel so that it moved the pointer all the way to the top of the tuning dial and then tightened the setscrews on the flywheel again and then checked the tracking and it definitely tracks much better now.

But there still seems to be a tracking issue with the FM Band because as I said 2 of the local Christian stations that are pretty close to each other on the tuning dial still crowd each other out (the stronger of the 2 stations which is a 50kW station, is the one that crowds out the 5kW Station because the 50kW station for some reason starts showing up at about 104.2 on the dial (its very faint starting there) and then gets blaring loud once it gets to 104.7 its actual home frquency, and then gets faint again until it disappears at around 105.5 (and the station that is being crowded off the dial is at 105.3, and it is barely audible on this radio as it is crowded out by cross-talk from 104.7).

Which the way this radio is acting is similar to an old TRF set, except this isn't a TRF set its a Superhet set with 3 IF Stages and an RF Stage for both AM and FM, so you would think that this set would have better selectivity than this, but it doesn't for some reason.

Any ideas as to what might be going on here?

vortalexfan, my guess would be that your set simply wasn't designed to have great FM selectivity, since the FM band was much less crowded back in the day. In those days, AM was still considered more important.

That makes sense, the mid-1960s was the the height of rock n' roll and most of that was still played on the AM band (and most cars back then still had AM only radios in them.)

OK, so I finally got around to completely recapping this radio (unfortunately I had some traces lift on me, even with using a 25w soldering iron, which is the lowest powered soldering iron one can get.)

With the radio recapped the radio works 100x better than it did before when I first got it, but then when I was trying to put the unit back together the wire lead for the (-) battery terminal broke off the board, and I am not sure where that wire lead goes to because I didn't pay attention to where it was connected to originally.

Does anyone on here know where the (-) battery terminal would of connected at on this radio? it works fine on 110V but I would also like to be able to use it on batteries as well.

I don't but my advice would be to look at the length to see likely spots for it to connect to, and use a magnifying glass to try and spot where the broken wires are poking out of some solder somewhere. You could probably trace the neg from the rectified AC and connect to a common trace.

It might be a mistake to use a low powered iron, as you have to dwell too long to get enough heat transfer to melt the solder, which will transfer into the PCB. A hot iron works better.

And yes, for those asking (albeit a while ago) Japan AM starts lower than 550, but I forget the exact number. I can only pick up 3 or 4 stations that are well away from the limits.

Just to set the record straight: The AM band in the USA is from 540-1700 kHz and has been for decades.

I think years ago (maybe 1930s or 1940s) the AM band used to go from 510 to 1525 or thereabouts, and then in the 1950s I think it went to 540-1650 and then I think the 1980s was when it went to 530-1710, and I think for a while in the late 1930s and early 1940s the AM band went from 540-1710 (1650-1710 was the old Police band and that was often times included on some of the higher end AM only radios.)

The only "hot iron" I have is a 1950s vintage Weller Dual Heat Soldering Gun that one of the settings is over 200 Watts and the other setting is over 300 watts which is probably overkill for PC Board work (but would be fine for a P2P wired metal chassis.)