And so to…the JBL Aeon.. again

This has been not unlike taking a shortcut to Blackpool via Bombay. I think we’ve covered most of the problems of the Universe, without actually solving any. Some days are just like that.

The fault that we had so much difficulty in describing (see previous blog on Aeon if confused. If not confused also see previous blog, should you wish to be) actually came down to a faulty gain/level pot on the back of the cabinet. This where we get into levels of sillyness that should be experienced to be believed. That’s not a recommendation, you understand.

All we have to do is replace the pot. OK? No, not ok. The pot has to fit on the small pcb in the pic, which is mounted on the back of the cabinet. OK? No, sadly, not ok. Our first problem is to get one of these pots. They’re about 50 pence and five legged cows are easier to find. My first port of call was CPC, then RS, then Farnell. Now, Farnell actually had one of these. In fact they about a million. They’re called P140 pattern pots and used a lot in current equipment, which is presumeably why you can’t get them. The only problem with Farnell was that they wanted to charge me £16 (that’s, say, $28) to ship this component (which weighs less than my wallet: that puts it well into minus figures) about 100 miles. I could have launched it to Pluto for less.

Needless to say, that wasn’t an option. So I sought  out JBL parts suppliers. They were in US and you couldn’t buy the 50 pence part, you could only buy the complete pcb assembly. They didn’t say why; maybe some common philosophy with Farnell  somewhere. Anyway the pcb was about $50 or so, and shipping as per Farnell would have been at least double the gross national debt. I let that go.

I eventually did it for nothing (not counting the years of toil it took to do the mod).

Here’s how. The pic below shows a hole (amongst other things). This is where the original pot fitted. Just above that are four screened cables. These were soldered to the pcb pads to which the original pot was soldered. 

 

This is where the cables go to. I drilled a hole in the back of the cabinet and fitted the pot I had hanging around on the shelves

(dual gang as the original spec).

If you ever get a chance to read ‘Zen and the Art of Motorcycle Maintenance’ just bear this in mind, particularly where he proposes fixing his friend’s BMW bike with a bit of coke can; much to the perfect horror of his friend, who prefers to spend a fortune on the correct part. Even though it’s more or less the same thing with ‘Coke’ written on it instead of ‘BMW’. No cigar for guessing which way I’d jump.

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