henrypaz
PLEASE: easy way to install hitachi carb? it took HOURs for 2 front nuts last time!
Posts: 106
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Post by henrypaz on Feb 20, 2015 20:39:31 GMT -5
Friends--
Being a curious guy, as I imagine most of you are, I wondered just what was inside the defunct "ignitor" of my '89. I had already replaced it, so I was sure it was bad and that It would be no loss to look into its innards. So I just whittled all of that plastic case away and what did I find?
Not Much! I found what looked like a power transistor, which is just what the FSM says it was. And it appeared for all the world to be nothing but a 2N3055 transistor which is common as dirt, and costs about $3,00 at Radio Shack. having learned this much, my overweening curiosity led me to do some experiments. I got some of those 2N3055 transistors and hooked them up to a good coil, and made that thing spark nicely.
For awhile. Eventually, I burned up my transistor. I don't think it happened because the experiment or the transistor was not the right kind, but rather, I am not a good electronics guy. I almost always burn up my transistors doing these backyard experiments.
So! What's next? I may try again. Or maybe some young Justy dude will pick up the banner and carry it on to success. I hope so. maybe some one will say,"Why spend a $100 on an " Ignitor", when a $3.00 transistor will do?
Good luck wit dat!
henry
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Post by nipper on Mar 21, 2015 21:59:15 GMT -5
It may be the heat load that killed the transistor, try putting it on a heat sink
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Post by kastein on Mar 28, 2015 0:02:56 GMT -5
Any chance you can post the writing, if any, that was on the transistor housing? Or some pictures of what you found in there? I'll see if I can figure out what the actual part is. It's probably just an NPN BJT or N-channel MOSFET acting as a low side driver for the ignition coil as you surmised, but a part number would definitely help me look up specs and find a suitable substitute if it is no longer available.
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henrypaz
PLEASE: easy way to install hitachi carb? it took HOURs for 2 front nuts last time!
Posts: 106
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Post by henrypaz on Mar 28, 2015 12:17:23 GMT -5
The only writing on the transistor case was the number "9103." No name. I couldn't find out anything about it on the internet pipes. Will you post what you find?
I did have a heat sink on my experiment, but am not sure I had saturated the transistor. i was also confused by issue of back EMF from the coil and voltage spikes. Someone mentioned using 'flywheel' diodes, which I bodgered around with.. I had a 555 timer in the system too, which was working well enough. Not sure my coil was top notch either. Lots of unknowns.
Glad for your interest and input too.
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Post by kastein on Mar 29, 2015 8:40:24 GMT -5
Flywheel or freewheel diodes generally are used to keep back EMF from destroying a driver transistor with an inductive load, so that does make sense. I like to use schottky diodes for this as they switch much faster than regular silicon diodes, which is critical in handling back EMF spikes.
9103 is likely the datecode, that is a standard format, 91 = 1991 and 03 = third week of year (late january), which makes sense as well. Too bad the part number isn't printed on the part, that makes things difficult.
I got a spare ignitor from a junkyard 1993 while picking up spare parts for my justy recovery trip last week, so I can give measuring parametrics a shot after work some night I guess once I check the wiring diagrams and find out which pin is which.
I will either post all info I find or not post it, as you desire. I am guessing by the fact that you made this thread that you would like it posted.
Edit: Basically back EMF is the way inductors respond to a sudden change in current flow. Inductor voltage is the inductance in henries times the instantaneous (derivative) change in current over time measured in amps per second, so you can see that if you suddenly turn off the driver transistor, the voltage will jump incredibly high very quickly which is a great way to kill the transistor. The problem is, this is part of how ignition transformers need to work, since they need to build a high voltage spike, so you have to allow a certain amount of current discontinuity to actually get a spark, just not enough to destroy the driver transistor. At least they use an external ignitor that can be replaced at all unlike mid 80s and early 90s Fords, which have it built into the ECU as far as I know and are famous for blowing up ECUs. One guess which part of the ECU burns out...
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henrypaz
PLEASE: easy way to install hitachi carb? it took HOURs for 2 front nuts last time!
Posts: 106
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Post by henrypaz on Apr 16, 2015 14:21:20 GMT -5
ken-yes post any and all that you find out re this device. I think of it as a communal property, not my own project.
Re the edit, that fits exactly with my thinking on it.....ie...needing that spike to make the spark happen.
I think if we can get a durable transistor in the circuit, it should be easy to make it work. I have NO experience with Schottky diodes. Do I hear they are sensitive to work with?
Thanks for your help/inteest in this
henry
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Post by kastein on Jul 16, 2015 12:25:26 GMT -5
They are somewhat sensitive but not overly so. Their chief benefits are that they have much lower forward voltage and switching times. The forward voltage is why they are used extensively in switch-mode power supplies (almost every computer power supply made today) and the switching time is why they are used as back EMF snubbers.
I have had next to no time to dedicate to this project unfortunately. Will get to it sometime, but getting my Justy running again is higher priority.
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henrypaz
PLEASE: easy way to install hitachi carb? it took HOURs for 2 front nuts last time!
Posts: 106
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Post by henrypaz on Mar 10, 2016 17:24:23 GMT -5
Justy Friends--
just a little update on this project:
It turns out that several chip manufacturers have chips that are specially designed to switch the primary of the ignition coil. One such is made by ST Microelectronics and the part number is VB525SP-E among others. Another is VB027 which is To-220 package, an older chip. these have all the goodies inside to clamp the voltage spike, and limit current, and other things. they are not very expensive--about $5.00 on eBay for instance.
My problem with completing this project is--I am a very incompetent electronics experimenter. Two year degree only. Just enough to always "let the smoke out" of my circuits. So, if anyone out there has enough expertise to carry this on and finish it, AND post the results with a schematic, we can use it to develop an open source Justy ignitor! I think that would be pretty cool.
thanks for thinking on this with me
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henrypaz
PLEASE: easy way to install hitachi carb? it took HOURs for 2 front nuts last time!
Posts: 106
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Post by henrypaz on Aug 22, 2016 20:41:56 GMT -5
just a little more re this project. A friend of mine wanted to make an electric fence to protect his bee-hives from the bears, which like to tear them up and get the honey.
I got a good signal generating circuit going with a 555 timer IC chip and some other little bits: ( 2N2222A transistor, TIP31 transistor and some electrolytic capacitors and some little resistors, and an 914 diode.) So that's all working well, and I am using it to drive a big ignition grade transistor, a MOTOROLA MJ10012 NPN. that thing is throwing a 1/4 inch spark that should deter any bear. And with a little TLC, it should run a Justy. I paid $7 at Amazon for it. had to buy 5 though, so I have some extras to sell.
The point of it all, is, that thing should replace the transistor inside the "ignitor", on a Justy. For $7 and not "massive" Subaru prices. ( I paid $100 for a complete ignition from the wreckers once.)
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Post by papcina on Aug 24, 2016 10:51:25 GMT -5
hi guys, i started a thread a couple of days ago, after i found out that it is the ignition module problem.... anyway, didn't saw this thread before, so maybe the admin can merge the topics here... in any case, look at my findings about the TO3 transistor on the link subarujusty.proboards.com/thread/6428/ignition-coil-swap-control-modulewhat do you say I try to replace the bad original transistor with the one from STmicroelectronics, BU941 (TO3 package)?
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Post by papcina on Aug 27, 2016 9:09:40 GMT -5
okay... some updates from me... i've tried to swap the broken transistor with an 2N3055 but for me it didn't work... i've ordered one BU390 NPN transistor over ebay so i'm waiting it... usually, all those ignition moduls in back were made out with BUX37 NPN Darlington transistor... equivalent for that one can be BU930, BU931, BU932, BUT51P... we will see how it ends... thanks!
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Post by papcina on Sept 4, 2016 1:49:27 GMT -5
Justy Friends-- just a little update on this project: It turns out that several chip manufacturers have chips that are specially designed to switch the primary of the ignition coil. One such is made by ST Microelectronics and the part number is VB525SP-E among others. Another is VB027 which is To-220 package, an older chip. these have all the goodies inside to clamp the voltage spike, and limit current, and other things. they are not very expensive--about $5.00 on eBay for instance. My problem with completing this project is--I am a very incompetent electronics experimenter. Two year degree only. Just enough to always "let the smoke out" of my circuits. So, if anyone out there has enough expertise to carry this on and finish it, AND post the results with a schematic, we can use it to develop an open source Justy ignitor! I think that would be pretty cool. thanks for thinking on this with me one question henrypaz, i don't get it maybe... I've ripped off the whole casing from the broken ignition module and there was a transistor in TO3 package... I am (still) waiting for the BU930 transistor (bought from eBay) to replace the original broken one and try it running with that one... Am I missing something? I don't see any more electronics in that module, except 5 wires and that transistor... so I don't know why you need an schematic for the circuit? or you just asking for the wire connections? originally I've replaced the broken transistor with the 2N3055, but it didn't work neither... have you done something else except replacing the 2N3055 transistor when it worked for you (before it burned out)? Thanks a lot!
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henrypaz
PLEASE: easy way to install hitachi carb? it took HOURs for 2 front nuts last time!
Posts: 106
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Post by henrypaz on Sept 10, 2016 14:38:21 GMT -5
okay... some updates from me... i've tried to swap the broken transistor with an 2N3055 but for me it didn't work... i've ordered one BU390 NPN transistor over ebay so i'm waiting it... usually, all those ignition moduls in back were made out with BUX37 NPN Darlington transistor... equivalent for that one can be BU930, BU931, BU932, BUT51P... we will see how it ends... thanks! Hey papcina--I just came across your post re the "Ignitor Sham" thingy. My latest thoughts/findings re the matter are-- One the "Ignitor" is Nothing but a beefy NPN power transistor Two The 2N3055 is not strong enough for the job. Three--I bought some Motorola MJ10012 NPN transistors that are working for me now in an automotive coil environment, using a 555 timer and some transistors, and a 0.047 microfarad ( I think ) capacator. The disclaimer here is.....I am only sparking one time per second. Why ? Because it is for a bear-deterrent fence for a cluster of bee-hives. It's been working for weeks now. The once/second spark, would of course, not stress it in the same manner as sparking at engine operating speeds. The heat generated is trivial at 1 Hz. The MJ10012 cost me $35 for 5 at Amazon.com Four--re the "schematic," that's not really necessary, just a description of what you eventually worked out. Just for the Justy folks to have access to. I am glad you are interested and working on this issue. We can call it the "Open Source Ignitor" when it's finished, huh? henry
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Post by papcina on Sept 12, 2016 2:54:07 GMT -5
thanks henrypaz! I'm still waiting the shipment of a BU930 NPN Darlington transistor that was used in that years to ignite the coils, as well the other similar transistor (BUX37 and so on), as soon I receive it I'll try to plug it in... by measuring the transistors, I think the dimensions of it should be correct and the same as the original broken one... In any case, if the thing doesn't work, I've found on ebay the same ignition module as used in Justy, but being sold for Nissan 200SX / Sentra car. Since it is a car company from Japan, I suppose they've used the same parts in different car types, at the moment I've found only that for those two the same ignition module, who knows in what other car types is installed. In any case, it is cheaper (100$) compared to the price asked here in Europe (300-500$). i.ebayimg.com/images/g/X2UAAOSw0kNXh~3z/s-l500.jpgI'll see, maybe it will work out with BU930, at least I hope so I'll keep you updated with this topic since I have to make the Justy work
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Post by papcina on Sept 23, 2016 11:51:59 GMT -5
tadaaaaaam!!!! problem solved! Justy running perfectly! Finally, the BU930 transistor came from eBay, soldered it to the wires and here it is so far okay... eBay, less than 5$ so if anyone has the same issue just get one NPN darlington transistor and replace it it should be one of these here BU930, BU931, BU932, BUT51P or BUX37 the biggest problem for me it was to rip off the plastic casing from the transistor, so be patient and remove it slowly... the rest of the process is easy.. good luck to everyone!
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Post by subru on Nov 2, 2016 16:36:23 GMT -5
I have done the same thing that you have done. And I still dont get any spark. I've changed all of the ignition parts and the fuel pump is working.
Does anyone know what causes this problem?!
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Post by papcina on Nov 3, 2016 15:31:25 GMT -5
are the connections intact? All wires connected? check the cap that goes to the coil if it is okay
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Post by subru on Nov 4, 2016 14:14:18 GMT -5
Everything is intact. I'm getting frustrated!
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Post by gearheadeh on Nov 5, 2016 19:04:10 GMT -5
I have done the same thing that you have done. And I still dont get any spark. I've changed all of the ignition parts and the fuel pump is working. Does anyone know what causes this problem?! t is a common fault for the wires to break and you can not tell, you need to use and Amp meter and check the Ohms resistance on each wire, best place to see that is on the connection just outside of the distributor towards the coil
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Post by subru on Nov 6, 2016 15:10:48 GMT -5
Those wires are fine. Could it be something with the ignition switch?
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