Tools, Sharpening and Power Machinery - info on Makita DC1470 charger needed

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lawrent
01-22-06, 01:31 PM
I have a Makita 6227D cordless drill. The charger blew it's mains fuse, and I diagnosed diode circuit ref D7 as short circuit. All attempts to find any info about this diode, marked as B22, or a service sheet, from various official Makita web sites round the world have met with either no response, or a "buy a new one" type answer :mad: The charger is easily accessible with 4 ordinary cross head screws, the PCB component refs clearly marked, and there are no 'no user serviceable parts inside' type stickers. To me, as an electronic service engineer of some 30 years experience, this means it is meant to be serviceable! Does anyone have access to a service sheet for a DC1470 charger, or know what a diode marked with 'B22' is? I'd eat humble pie and take it to a service centre, but as I live & work in Fiji this isn't an option. Help!


chandler
01-22-06, 02:04 PM
There's one for sale on ebay at this moment for 10 bucks plus shipping. Time is worth something, and I have found that trying to fix something like this will take an eternity, even if you find the parts.

lawrent
01-22-06, 03:06 PM
Many thanks for your swift advisory Chandler - your solution may turn out to be the right one in the end. But - where I am (Fiji) makes this option lengthy and expensive - even at 10 bucks initial price and especially factoring in the, err, vagaries of the Fijian customs department . . . Not only that but it rankles when I look at a that barely one-eighth inch long, 5 cent diode that is so easy to change. I may sound silly, but there is a principle here. I don't understand why a company like Makita, which makes excellent power tools, fails to make a simple service sheet or any info available, especially considering the superb service sheet they freely supply for the drill itself. Surely a cordless drill consists of the machine itself AND the charger - ? It can't work without both, after all - they are a unit. Whilst my two batteries are still charged I will continue to persue the repair option! It may be that I should look to an electronic forum for a diode type B22 - but with a drill as popular as the 6227D I'd be surprised if this was an isolated event.


mango man
01-22-06, 03:35 PM
I would contact the president of makita for you region and send him the request expalining your circumstances .

chandler
01-22-06, 08:08 PM
Fiji...that's San Francisco and take a left, correct? I understand your problem, in that shipping would be prohibitive. I also agree with mango man that there should be some sort of resolution from Makita. Their customer service should be able to do something. Gee! Good luck with the charger. Wish I had a better solution.

md2lgyk
01-24-06, 10:20 AM
B22 is a standard voltage regulator diode. Here's more about it than you'd ever want to know:

http://www.semiconductors.philips.com/pip/BZX884-C12.html

Just scroll down until you find B22.

lawrent
01-24-06, 02:37 PM
Thanks for your help in solving this, md2lgyk. The right diode is actually a BZX79B22, a 22 volt zenner, glass encapsulated. I should have known this by looking more closely at the circuit in the first place - the 'B' prefix threw me - I am used to seeing 'C' as a voltage prefix with zenners. Enough - no excuses - thanks to you all who helped. I will be writing to Makita about the lack of charger schematic, not to mention their seeming unwillingness help. This thread can rest now.