Original Message: ----------------- From: Walter Coe Whalt@xxxxxxx Date: Thu, 7 Nov 2002 03:08:55 -0500 To: DMCForum@xxxxxxxxxxxxxxx Subject: [DMCForum] OEM door lock module Q&A > If the diode is protection, would the door locks work without it?? Yes, certainly. >> For a while. It's there to protect the trannies. I hope I haven't lost you in the technical jargon. The diode is primarily protecting the rest of the door lock module, but it also protects the whole car per se. Even while the car is not running, the diode is still connected across the battery. You could put a dozen of these diodes at different points throughout the car and it wouldn't make much of a difference. The diode tends to protect the devices that it is closest to. >> The nature of the transient response of a long bit of wire means that all these distributed diodes protect th devices they're in. > If not, are there any other parts that could be replaced that would have been damaged?? Not likely. The most sensitive parts in any device are the semi-conductor junctions. >> Personally I replace the main timing caps too - on the most recent one I've done, I've dropped the value to 470uF because the new relays draw much less current and consequently stay on longer than they need to with the original 1000uF caps. After 21 years those caps aren't up to much and may well cause current leakage. At the time I glanced it over and have not yet read all of it. I trust that the transistor that the author suggests for replacement is well suited for the job. >> There are manu out there that will. In fact the OEM one is a crap choice. A 2n2222 will take 2A and costs a few pence. Method 2: This one is promoted by Martin Gutkowski. The fix is to replace the weak OEM relays with better ones that are hermetically sealed (air tight with inert gas inside). Even though the relay contacts are still released slowly which promote arcing, the contacts have no flammable >> Ionisable :-) air around to burn them. I consider this an elegant fix and admire Martin's ability to have thought this through. >> Actually it was a happy accident on the relays I found. The last I heard, Martin was offering for people to send him their old modules for upgrades using the sealed relays he found. He was willing to do this at minimal cost. >> Hehehehe but wait for me to get around to it :-) After doing 3 or 4 it got extremely tedious! I have a couple on my desk awaiting attention. In all honesty though the design is that poor I really should get around to building my little replacement design: www.delorean.co.uk/electronics/lockmodule.jpg (some component values are not correct). I won't say this design is correct in a purist sense - I'm using the trigger level of CMOS logic for example when I really should use a comparator, but it'll work fine and timing is not that critical. Adjusting C4 and C5 with R8 and R9 twiddles the time the solenoids are energised. (t=1/CR where t= time it takes C to charge to 66% of supply). This design would be tiny - and those BUK switches are lovely! With the space saved I was intending on squeezing the remote starter's door launcher control into the same box. Right now though I'm having more fun working on the more important parts of my car! > maybe he can tell you where he found those relays as I know sealed ones are rather unusual and hard to find. I got them from www.maplin.co.uk stock code YX97F (at least that's what I think they now are - the ones I have are black) Martin #1458 #4426 -------------------------------------------------------------------- mail2web - Check your email from the web at http://mail2web.com/ . To unsubscribe from this group, send an email to: DMCForum-unsubscribe@xxxxxxxxxxxxxxx Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
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