3 cd stereo

Aiwa is not a weird brand. It is part of the Sony group, and is very common. The most likely thing on one of these - assuming that it's one of the carousel models - is that the laser lens is very dusty. In their heyday, I used to do probably 4 or 5 a week. Cleaning the lens - properly , that is, not with a 'CD lens-cleaner disc' - will restore one of these in 7 out of 10 cases. Failing that, you're probably up for a replacement laser. There are a couple of other potential issues which have been known to stop one working, but they are very rare. The decoder / deck drive electronics are generally very reliable on them. If you do have to get a replacement laser, make sure that you get the right one. KSS 213B is the commonest (and cheapest), but they have also had '213C, '213D, and '213E fitted. They don't like having the wrong one in them. None of them is expensive as lasers go, but I would warn against using the real 'cheapies' in these units, particularly if it's not a '213B, as in my experience, operation can be a bit marginal with a less than full spec laser fitted.

Arfa

Very nice post indeed Arf, but I doubt anyone who thinks Aiwa a weird brand has the potential to do anything but swab the laser if he/she can even do that :)

Hi Meat - how's it a'goin?

That did occur to me too, but I thought it was a nice example of 'one of those' questions relating to what is actually a very common stereo with a very common problem, and I thought it might serve as a useful vehicle for one of those magazine type "Uncle Arfa Answers ... " responses that could be useful to others with a bit more experience ;~}

Arfa

LOL Uncle Arfa's Answers. I'll archive these from time to time just in case a friend or someone asks me a question here. I basically dropped that line of stuff years ago and focused on vintage tube guitar amps for my brother in law's music store. He's kind of nuts and will buy these off the wall tube amps from street walk ins. I worked on an Alamo Montclair 1x12 he bought from a walk in. Needed some minor things, tube, resistor, etc... Nice little 22watt amp, great for blues as it breaks up nicely for that tube amp distortion before it gets too loud. Myself the smallest amp I have is a Laney Pro Tube 50 watt that sounds like a 100 watts. The rest of my tube amps are all 130+ watts RMS :)

I do a lot of guitar amps as well for the music store in the village where I live. I have just today been doing a Studiomaster 400 mixer / amp that had the LED bars both illuminated and behaving very oddly, and no output from either main output channel. I had to shell out $20 for a schematic-set download. The two final mixdown boards, are the same, but different ... !! One uses opamps with a standard 8 pin DIL package, and the other uses different opamps in 8 pin SILs. I've never managed to find anyone here who supplies those SIL opamps. Oddly, the same stage was faulty on both boards, and I suspect that something nasty must have been jacked into the insert sockets. I replaced both chips, using a standard DIL standing on end with wires to the other four pins, for the SIL one. That restored all the mixer functions, only to find that one power amp didn't work. There are 8 transistors blown, and the reason it just sits there quietly with no blowing fuses or flames, is that it's full of safety R's, which are all open circuit.

Last week I did a Marshall with both output IC's blown to pieces. They are the size of something in a car radio, and have 96v across them !!! I also had another Marshall that had three 5.3 ohm speakers in series in the cab - very odd arrangement to make up 16 ohms. One of the speakers was short circuit, and someone had screwed about with the wiring to try to compensate. The new speaker sent by Marshall was an 8 ohm - so much for their clever impedance calculations. When all fitted, the amp output seemed low, and lacking in 'zing'. Turned out a screen feed R on one of the output tubes was open. Sounded a treat when it had been replaced.

I don't know about you, but I find this interesting and varied work, and there doesn't seem to be too many of us about still doing it - particularly on tube equipment. All of the young engineers and fellow radio hams that I know, are terrified of tubes and the high voltages involved, and won't go near them. I make up the rest of my work with hifi equipment - some of it very high end from the nearby town's last remaining 'proper' specialist hifi store, and some of it basically junk, that comes to me through the last few independant retailers in the area. I only do trade work, as I can't be bothered with whining customers. I also have a 'commercial' contract to repair pcb's from drinks vending machines. No service info, but I rev-eng'd one a long time ago, and built a jig to test every function very rapidly. Takes me about 10 seconds to test and diagnose each board. VERY boring and repetitive work, but good bread and butter money for the business.

Arfa

shows what you two know! the cd tray was pulled out and wouldn't go back in. i was able to put it back in. also could something like that actualy brack the laser. if i need a new laser were would i get one. eather on line or what kind of shop would i need to go to to get that.

THe last mixing console I worked on was a few years back and as a favor repaid. It was a 24 channel Mackie that needed new faders(sliders)after beer was spilled in it. In order to get to them I had to remove all the knobs for each channel, must have been 200 of them, about a 100 screws and that allowed me to pull the top off enough to get at the 4 banks of 6 faders that were soldered onto 2 peripheral boards. Luckily all the trim pots for each channel did not have a nut and washer. I think I spent more than 2 hours just dissembling it. Total time from start to finish was probably 6 hours.

LOL I've seen all kinds of idiots bring in 4x12 cabs with some really whacked out things inside. BTW my Waller DSP 100 2x12 combo amp has a TDA something or another for it's power output. It sits on 90 volt rails and is the size of a car stereo amp chip. It had a digital hum problem shortly after I purchased it. The said send the chassis back to them so they could do some ground lift mod. I gave them my credentials and they emailed me the procedure complete with illustrated pics and allowed me to do the warranty :)

I love high voltages and tubes. The smell of rarefied air and ozone. The knowledge that you could die instantly if you grab the wrong thing in say an Ameritron legal limit amp with a 3CX1500A inside. If you have the time Arfa, have a look here

If you like power and volts and tubes, this is WLW in Ohio formerly 500 thousand watts :)

On Mon, 25 Jun 2007 17:49:39 -0700, jon puked:

Who is this "you two" that you refer to?

And for living in the usa posting from a netblock owned by an EDU, you sure can't spell worth a shit.

If by "you two" you are referring to me and Meat, I think you would find that between the pair of us, we have forgotton more than you will ever know ... If you had a tray problem in the first place, then you should have said so. If you did manage to get it back in without screwing the timing, you are a very lucky person. As far as getting a new laser goes, Google it.

Arfa

Arfa Daily wrote: I have just today been doing a Studiomaster 400 mixer / amp. I had to shell out $20 for a schematic-set

You shoulda emailed me...

Ron(UK)

Next time I need something, I will !! Never even thought to post here to be honest. Thanks for the offer anyway Ron. Did you see the 'note' I sent you in one of the other posts ref Elektor mag and audio modules ?

Arfa

Yes thanks, tho I don't read any of the punter mags anymore, I`m sure ILP will put the review on their website presuming it`s favourable.

Ron(UK)

That's a very good site. The tubes in the high power tx seem smaller than the ones we had here. I live not far from the famous Borough Hill BBC transmission site at Daventry, and went there several times on college field trips. The Third Programme transmitter that used to be located there, radiated 200kW during the daylight hours, and 470kW at night. The antenna was a lattice vertical dipole, located about a mile or so across fields from the transmitter house. It used an 'open wire' feeder made from 3/4" copper water pipe on 11 foot wooden telephone poles. I remember commenting to one of the transmitter engineers that was showing us round, that the feeder losses must be colossal. Not really, he said, only about 10kW ! Each half of the mast was fed by a separate final cabinet. I remember asking the same guy, naiive as I was, what would be the effect of one of the halves of the tx failing. He asked if they taught us nothing at college and said to just think about it. He said that one half of the tx stopping would represent only a 3dB drop in output power, and it would only be noticed at the fringes !!

The tank coils for the finals, were mounted on trolleys that ran on rails, so could be moved from cab to cab for frequency changes. The coupling was achieved courtesy of brass yardsticks set in the floor, and hand-written charts of measurements for different frequencies. I can also remember seeing those big old brown bakalite cased silver mica caps, strung across the insides of the cabs on long wires, apparently to kill internal resonances. This is all long wave stuff of course, but there were also many short wave transmitters on the site, sadly all gone now.

The finals, as I recall, were steam cooled, and the steam used to heat the buildings. As I say, the PA tubes were big things, also trolley mounted I seem to remember, predominantly glass, and with big nuts and bolts inside. The warranty started from the time they were delivered, so new or rebuilt ones were always put into service immediately to get the warranty period out of them, before being removed again, and put into stock. Happy days. I tried to find some pictures on the net to show you, but there seems to be very few surviving, which is odd as it was a very famous transmitter site, and also had a very active ham radio club located there.

Arfa

Here's a piccy of one of the output tubes that I just found. Looks like it does 250kW in one, rather than the 5 smaller tubes in the WLW transmitter, but you can see the huge difference in size

Arfa

Too bad you don't have a link for that stuff I'd love to see the hardware.

Holy Moses!! Now that's a final. The WLW Western Electric 500K was built back in the 20's if I recall. That's why they needed six different transmitters to obtain that wattage (available technology)

Cool. Looks like I could cook my lunch in/on it! :)

I was thinking the same thing with that heater in the bottom looking like it came out of a big ass electric oven.

Yeah. These big old tubes are gorgeous aren't they ? I'm not sure when that transmitter dates back to, but it's got to be a long way. The BBC have had a transmitter site on that hill near Daventry since the year dot, and the Third Programme (later renamed Radio 3) has been going virtually as long as the BBC themselves. I have a vague suspicion that the main transmitter was originally at the Droitwich site, but I could be completely wrong there. I'll have to have a bit more of a nose around on the 'net. They used to have a real antenna farm there as well. The World Service was relayed from there on short wave SSB transmitters, feeding wire-and-mast slewable rhombics. You used to get a fantastic view of it all from the nearby railway line, but as I said, nothing much there now except SHF telemetry relays and cellphone stuff.

Arfa