Green Wagon Posted August 17, 2015 Posted August 17, 2015 (edited) Briefly, the JBL L212 is the 70's (?) version of a sub/sat system. The bass amp (Bass energiser) is of such an age now that they need reworking. This one had been worked on previously. I'll let you judge the 'workmanship' for your self........ Due to it's age, condition, unknown state, and rarity, I ended up spending ~2 weeks on it. Thats not including the month I spent waiting for parts. Lots of parts. Soooooooo many parts.... Actually, the only remnant of the original is the metal work, transformer and circuit board. Oh, and a few unobtanium diodes (ms700) that even the replacements have been unavailable for over 10 years. Mind you, I was so sorely tempted to un-rivit the board and make a new one. One of those boards that just loves to spit tracks with no provocation. Helped by the fact that jbl decided it was a great idea to fold the legs on to the tracks before soldering them. I HATE that. And it really boils my ham that I had no option but to do the same as the tracks are just that bad. I'm sure the owner will throw in his thoughts and info regarding the system. Anywho. Time for porn. Keep in mind this section bolts to the bottom of the sub enclosure (scroll down if your impatient ) Before work commenced. Oh lookie. what should be 4 filter caps is 3. They call me, Tripod................ Main section removed from mounting plate. Hmm, someone gave it a little bit too much power. Bottom left, arcing between tracks on the input section.. Also several input filter caps had been removed, One top left (open holes) and one on the actual level control (Cross cap later pics) And some nice magic smoke that escaped. Yes, theres supposed to be an input filter cap in 'C1'. Wheres wally ? And here we go. Remove some bits, clean the board, put new uprated bits back in. Sigh. I think the tracks really wanted to be somewhere else.. Part of the previous, um, repair ?? To be honest they didn't do to badly in some ways. Just cut a few corners in important areas. Lets drill some holes for the new filter caps. Finally. Progress. Some will notice the new proper bridge rectifier, and all the new output transistors. Nothing escaped. Nothing... Then a good check over with a magnifier, flux clean, and recheck before reassembly starts. Oh but wait, before that gets done, I need to do some mods to make it more user friendly for todays young whipper snappers. Power switch was actually split and about to fall apart, So, new switches and led power light to make sure it lasts for another 30 years. And it all goes into the base of the sub enclosure... Edited August 17, 2015 by Green Wagon 2
kelossus Posted August 17, 2015 Posted August 17, 2015 (edited) Wow, alot of work definitely went into this beast.......As Nigel knows I like to have everything in original condition and most people wouldn't have even bothered going to such lengths to restore something. I like to keep Nigel busy though and he always does such a neat job........ Already thinking about my next project.....Maybe Charge Couple Crossovers........ Haven't had a chance to set up the system yet but this active sub will rotate between my L20T3's and L212's. Edited August 17, 2015 by kelossus
Equaliser Posted August 18, 2015 Posted August 18, 2015 Nigel do you supply the Vishay resistors from your store or was this a custom order off Mouser?
Green Wagon Posted August 18, 2015 Author Posted August 18, 2015 Heya, No and No. 95% was ordered through farnels. (resistors, caps, semis) 4% through rs. (switches and led) 1% through me (The cross cap)
Equaliser Posted August 18, 2015 Posted August 18, 2015 Damn. I'd be over the moon if there was a supplier for good resistors in Australia. I've stopped my orders completely from PCX and Hificollective due to our schit AUD.
Green Wagon Posted August 19, 2015 Author Posted August 19, 2015 As all my stock comes from o/s (euro), I'd love to hear more about this wonderful exchange rate Oh, and then theres the parts I'm buying from usa to fix my old automotive brick. Somehow, even with freight, it's still cheaper to buy vovo bits from 'merica. Australian bricks and mortar, I'd love to support you, but $180 to your counter + 3 weeks wait, just doesn't compare to $100 with 5 day freight to my door.
Green Wagon Posted November 24, 2015 Author Posted November 24, 2015 Update. The Satellites have been rebuilt, here -> http://www.stereo.net.au/forums/index.php/topic/92906-jbl-l212-satellites/
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