Performance CDI layout and schematic diagrams

[ivan H]

See post #18 to view these two pix in a readable format. Thank you very much for ur assistance with this KCVale. Greatly appreciated. Ivan
Important Note; The SCR must be put in the right way. Positioned as shown on the layout, the side with writting on is facing UP. The SCR has been bent back to be lying flat against the board.


Ok, if u cant properly read the resistance values (in blue), they are; across the top, left to right; 16 ohm, 120 ohm, &220 ohm.
Next down, running along the right side of the SCR (as seen here); 390 ohm.
Next down, along bottom of SCR (as seen here); 1k.
Next down; 33 ohm.
The next down, & last is amongst the timing caps; 760 ohm.
The small caps near the 760 ohm are the 35V Tantalum's & from left to right are;
0.47uf (on a jumper to ground)
4.7uf (next to 760 ohm resistor). Both cap & resistor go directly to ground;
0.47uf (on jumper to ground):
The + marked leg of the 3 tantalum caps must go to ground (or jumper for the 0.47uf's).
Hope this helps.


Ok, hand drawn layout & schematic for the stock aftermarket CDI. If u click on them u'll get a full screen photobucket pic. They arent in a seperate album so u can also check out my switchable #39/#36 modified marshall amp clone (as used by Slash for rehersals (#39) & recording (#36) of Appetite For Destruction) in various states of construction. Wicked sounding amp, but thats another story.
U might notice 2 differences between the layout & schematic.
(1); the layout shows a 16 ohm resistor where the schematic shows a 15 & a 1 ohm in series. The jag uses 5% carbon film resistors & a 16 ohm isnt available in this type. I use 1% tolerance metal film resistors & a 16 ohm is available in this type. Use the 1% metal film type, 1/2 watt. They are better quality & closer tolerance, & cost a couple of cents more than the carbon film type.
(2); The layout shows two 0.47uf charge caps while the schematic shows one 1uf. Adds up to the same thing.
I'll get the complete component list up after I knock off this arvo. If anyone has any construction questions dont hesitate to ask. Till later this arvo, cheers

 

[ivan H]

Firstly, sorry for the low quality layout pic, I'm not equipped for this digital age.

Resistors, which are colored blue on the layout. They are 1/2 watt, 1% tolerance metal film resistors. U will need one each of the following;
16 ohm
33 ohm
120 ohm
220 ohm
390 ohm
760 ohm
(or make up by using a 750 & 10 ohm)
1k.
Make up a 760 ohm resistor from a 750 ohm & a 10 ohm by putting them in series. Put the 2 resistors side by side. Now twist the leads at one end together & solder them. Clip off the excess. So now u have the leads at one end joined & two leads at the other end. There is ur 760 ohm resistor. Should u choose to save 20 odd cents by using 5 or 10% tolerance carbon film resistors u will need to also make a 16 ohm resistor out of a 1 ohm & a 15 ohm resistot the same way.

The SCR (silicon controlled rectifier) is a
C106D1.
Get a quality one.

Diodes. U will need 5 of.
IN4007.

All capacitors are colored yellow on the layout.
35Volt Tantalum.
One of 4.7uf
Two of 0.47uf.

Charge caps are 275VAC, X2 type polypropylene capacitors. U can use either one of
1uf
or two of
0.47uf.
X2 is a designation & doesnt mean times two. Be sure to use X2 type polypropylene capacitors as they are rated to handle AC voltage. If u use polypropylene caps like maybe audio coupling caps with a DC voltage rating of 400 or even 630 volts they wont work properly as their voltage rating shows the DC voltage that they are rated to block, while passing AC audio signals thru them. Likewise polypropylene caps used for speaker crossovers wont work.

U will also need pins for the jumpers, 8 pins in total but u cant buy that small an amout. U can get strips of about 25 for cents. Use either
Dual Inline Jumper Pins
or
Header Terminal Pins
also a small pack of
Jumper Shunts.
The jumper shunts are the little things that are either plugged onto the pins or removed from to adjust timing parameters.

The only other thing is a small piece of
Vero Board.
Get the small size which will measure about 75mm x 95mm
or 3"x 3.75".
This board has hole spacing of 2.5mm & the copper foil side has strips of copper foil connecting rows of holes.
I use a piece measuring
67 x 47mm or
2.65" x 1.85", arranged so the long side is across the bottom (horizontal) & the copper foil strips laid vertically, or crossing the boards width. This will fit the layout pretty well.

U will need a small amount of resin cored solder. 60% tin, 40% lead is fine & solder wire with a diameter of 0.7mm is good. U dont want it too thick & never use acid cored solder for electronics as the acid will continually etch the metals resulting in bad connections that cant be easilly cured.

 

[ivan H]

Ok, u want to cut ur 67 x 47mm piece of board so that the copper foil tracks lie across the shortest side (47mm), so when the long side is placed horizontally the tracks are all vertical. U'll end up with 18 holes across the shortest side & either 25 or 26 holes along the length of the board (the holes arent always exactly spaced).
Ok, the components are mounted on the side WITHOUT copper foil tracks, with their leads bent at 90 degrees & inserted thru the holes.
On the layout u will see it is covered in little black dots. These represent the holes in the board & the components lead spacing on the layout is exactly as u will need so u can count the dots sortta thing to know where they go. U will also notice on the layout that all component leads terminate in an orange stripe. The orange stripe represenys the copper foil track on the UNDERSIDE of the board that u solder them to.
The only areas that can be tricky is where the jumper pins are mounted & I recommend u count the holes to wori out where this area will be & the remove the portion of track between the 2 lots of pins, & also lightly groove the board between the little short pads & the long track running down the boards edge. U dont have to do this but it will help avoid solder bridging the tracks.
Note; ur Tantalum timing caps will be very much smaller that drawn in the layout, the 4.7uf will be about the size of a match head & the two 0.47uf's will be smaller again. U will probably need a magnifying glass to see the + marked leg, which MUST go toward the jumper pin, or ground. This is because these caps are opperating under a negative voltage.
The green wire link shown on the layout is exactly that, an insulated wire linking the ground on one side of the board (where the black lead from ur magneto attaches) to the other side of to board to provide the ground needed there.
The SCR is mounted with the side with writting on it facing UP, so u can see the writting when its on the board.
Dependinf on the physical size of ur charge caps, this is the only part that may not exactly match the layout. Simply adjust the end that goes to ur coil to suit.
Ur IN4007 diodes will have a black tubular body with a silver band at one end. They are shown on the layout & schematic as an arrow head with a bar across the point. The bar represents the silver band & they MUST be orientated as shown on the layout.
U can attach ur leads either with pins (u will have extra jumper pins) or by drilling the hole in the board a little larger & inserting the wire thru (wot I do).
When its soldered up I dremel all unused copper foil tracks off with a small carbide bit.
The SCR's legs are bent apart a little to provide 1 hole space between them.
A soldering iron in the viscinity of 15 ~ 20 watts is fine, dont use one that is intended for heavy work. A small butane fuelled iron is also fine.
If u arent practised at soldering, no problem. Watch a utube soldering guide & have a bit of a practise on somerhing first, its really quite simple & can be learned in short order. I gave a lowdown on in the "build a performance CDI" thread that gives all the do's & dont's.
Now have at it. If u follow the layout it should work without any trouble at all.
I use a drop of silicon or epoxy thru the hole in the body of the SCR to fix it to the board (vibration) & also a bit on the long sides of the charge caps (bridigng cap to board) for the same reason.

How the circuit work is really quite simple so we'll get into that, going thru wot affect wot timing wise & how we can go about modifying the circuit to change various (all) parameters of the timing curve should u feel the need to. Oh, & I wont forget to post a simple test to ensure ur SCR is working correctly so u dont wack a faulty one in there if u buy from ebay (we know all about Chinese quality control, right?).
Cheers

 

[Huffydavidson]

Regarding the 760 , can a 768 metal 1/2 watt 1 o/o be adequate because that's what Muser carriers?

 

[ivan H]

SIMPLE SCR TEST.

Ok, for this u will need a 6 volt battery (or batteties to make 6v) & a small, low wattage 6 volt light bulb. 0.4 watt or 0.7 watt will be fine. U will also need to be able to secure a lead to each terminal of the battery & also to each terminal of the light bulb (not by holding them on).
Ok, u need to know wot the terminals, or legs of the SCR are. With the writtimg on the SCR facing u & the legs at the bottom, the legs are, from left to right;
Cathode (K): Anode (A); Gate (G).
Ok, connect the Negative terminal of the battery to the SCR's Cathode (K). Connect the positive terminal of the battery to one terminal of the light bulb. Connect the other terminal of the light bulb to the SCR's Anode (A).
The light bulb should be OFF. If it is on ur SCR is no good.
Now briefly short the SCR's Gate (G) to the Anode (A).
The light bulb should light up & stay lit up even without the Gate & Anode shorted.
If the light bulb doesnt light up when u connect the Gate & Anode or if it doesnt stay lit up when u disconnect the Gate from the Anode, ur SCR is no good.
Now disconnect something to switch off the light bulb & disconnect it from ur good SCR.
Cheers

 

[ivan H]

Hi Huffydavidson, did u mean the numbers on the resistors on the drawings here or the ones I emailed u last week? Or both?
If u have the abilty, perhaps u could assist by posting a layout & schematic drawn on a computer, as I neither have, nor know how to opperate one.
I dont know about on a computer, but with my phone I can click on the pix here to view them on photobucket fullscreen, then magnify them to be able to read everything. If this cant be done on a computer I appologise but there isnt much I can do about. I have been trying to get them up here for a long while for everyones benefit & this is kinda a last resort.
Yes, it is fine to substitute a 760 ohm with a 768 ohm. The normal Jag unit (from the pics I've seen posted here), use 5% tolerance carbon film resistors, which means they can vary 5% either way from their nominal value, which for a 760 ohm means roughly 38 ohms above or below 760. This is why I recommend using 1% tolerance. I recommend metal films as they are superior in all ways to carbon film. I recommend Tantalum for the timing caps as they are very stable in timing networks.
Using a 768 ohm resistor will slightly alter the point in the timing curve at which it starts retarding, but I do mean slightly. Cheers

 

[Huffydavidson]

Ivan , both my e-mail and here. Yes the numbers on the resistors . I get info and I'm back in the laboratory . BOOHAHAHA. It will come to life. BOOHAHAHA. LOL The numbers are blurry. Far as the768 I thought the same thing . (within recommended value). I've Incorporated a barrel switch furnishing lock as well . I'll send you a pic. Thx HD

 

[Huffydavidson]

O ya, I order the charge caps from China. They be yellers . LMAO

 

[ivan H]

Hi HD, most electronic components origonate from China, Korea, Taiwan etc. So long as they meet international standards is fine. I use charge caps made by SR passives.
U own a Jag CDI, yes? The closest I've been to one is pics on this forum. If there's anything else u need to know, uno.
Should anyone need to know the resistance values or their placing on the layout (until I can get a clearer one up) just yell out. Cheers

 

[Huffydavidson]

I just e-mailed you pics of my JAG. In the morning I'll take some reallllllyyyyyy up close pics and send them to you Ivan. This way we can develop an even better, performing unit !!!!.

 

[ivan H]

Hi HD, most electronic components origonate from China, Korea, Taiwan etc. So long as they meet international standards is fine. I use charge caps made by SR passives.
U own a Jag CDI, yes? The closest I've been to one is pics on this forum. If there's anything else u need to know, uno.
LMAO indeed.
Should anyone need to know the resistance values or their placing on the layout (until I can get a clearer one up) just yell out.

Ok, I edited the 1st post, putting the resistance values & their positioning on the layout underneath the layout. Hopefully this helps. There is only 7 resistors in all so it shouldnt be too confusing. In a few days time, if people are intetested, I'll get into some simple modifications to change the timing parameters. I gave some info on this in another thread, but we can take a simpler aproach that may be more flexible in regard to adjustability. Cheers

 

[ivan H]

Hi HD, I got pix, thanks.
Cheers

 

[Huffydavidson]

Hey Ivan, one thing needs to brought into focus , and that is I can't read the caps . Get back to us.
Thax sollu
HD

 

[ivan H]

Hi, I will try to get a clearer pic u.
The 2 large caps (polypropylene charge caps) are both 0.47uf/275VAC.
The small timing caps, reading from left to right (as seen here) are;
0.47uf (on a jumper to ground);
4.7uf (next to the 760 ohm resistor). Both the cap & resistor are connected directly to ground;
0.47uf (on a jumper to ground):
The small caps in the same area as the 760 ohm resistor are the 35V Tantalum timing caps. It is important that their + marked leg goes to ground (the jumper for the two 0.47uf's).
I put this info below the layout along with the resistance values.
If anyone at all can assist in getting a decent layout & schematic up here it would be greatly apprecitated. If u need to know anything to do this u can PM me (include ur email address will make it easy).
Cheers

 

[Huffydavidson]

Hey Ivan, So moving right along with this , here's the next technical questions .
#1) Can we safely assume that the jumpers on the magneto side are the lower timing curve meaning
0 - 3800 rpm ??
#2) And the the jumpers on the coil side ( timing caps ) are the retard/advance ??
#3) If this correct and accurate , the JAG graphs and charts will fall into play??

 

[ivan H]

Hi HD, the jumpers on the 220 ohm resistor & on the 120 ohm resistor are the ones that affect the Low speed, or RPM operation (mostly). These are the ones u test for best Low speed pulling power with. They affect the initial firing point & placement of the whole timing curve in regard to TDC. No jumpers on is the most advanced setting, followed by adding the jumper on the 220 ohm, next with no jumper on the 220 but a jumper on the 120, & lastly with a jumper on both resistors being the most retarded setting. Wot is actually happening when u add the jumpers is that they arr being put in parallel with the 16 ohm resistor, thus lowering its value. Adding the 220 brings it down to about 14.9 ohms. Adding the 120 brings it down to about 14.117 ohms & jumpering in both resistors brings it down to about 13.3 ohms.
So reducing the 16 ohm resistors value moves the whole timing curve retarded. If u increase its value it will do the opposite & advance the whole timimg curve.
The other two jumpers affect ONLY THE HI RPM RETARD portion of the timing curve. Hope this helps. Cheers.

 

[ivan H]

Ok, these are fine for use with a general purpose, daily ride type motor but they are not suited to a race type motor. The main drawback is that they retard too far to let the motor develop the sort of revs u would want. To change this u need to loose some capacitance in the r/c timing network. The main cap there is a 4.7uf. The next value down is a 3.3uf & so if u replace the 4.7uf with a 3.3uf it should allow it to rev a good bit higher. Other smaller values are available for fine tuning, instead of just the 0.47uf. 0.1uf, 0.22uf & 0.33uf can all be used & a bit of thought about fine tuning the same way u do with the jumpers ion the 0.47uf's is all that is needed to fine tune ur retard curve to ur motors needs. Cheers

 

[KCvale]

Thanks for sharing the diagram.
Photobucket sucks but your 1024x768 pics are great so I oriented the colored one properly and put both pics up on my server for you to share full size.

http://KCsBikes.com/pics/IvanCDI-1.jpg

http://KCsBikes.com/pics/IvanCDI-2.jpg

Link them how you see fit or I'll take them down if you want, just trying to help ;-}

Any reason you can think of why you couldn't use this 20Ω pot for your 3 resister 2 jumper trimming?

http://www.mouser.com/ProductDetail...=sGAEpiMZZMtC25l1F4XBU7XpbFdDDzhrp5j7mmWEE18=

Another option for the 2 cap jumpers would be a little PCB mount 2 pole dip switch or little 3 position rotary.

The point is with a little effort you or jag could actually make a sealed enclosed box with external adjusters and even put a keylock switch in the thing like I did on the stock CDI's for awhile.

Just food for thought.

 

[Huffydavidson]

Deleted do to incorrect information.

 

[ivan H]

Hi KCValue, thank you very much for that, much, much better. Ur question about the minature pots fits in perfectly with the next step I was meaning to describe;
continually variable initial timing setting between a point a bit advanced of the normal most advanced setting, thru to the most retarded setting by using a minature 25 turn 250 ohm vertical trim pot. As HD said, vibration can be a real problem (tho the multi turn pots cope with this much better). The answer would be to tune using the pot, then remove it without changing the position of rotation, then measure from to find the resistance across it & make up a resistor of the same (or as close as possible) value to solder in. (In a race type CDI I wouldnt want jumpers).
So, u wiuld need;
an 18 ohm resistor;
a 51 ohm resistor;
a minature, 25 turn, 250 ohm vertical trim pot.

The trim pot is a little plastic block with 3 connections (pins) exiting the bottom & a small screw head at one end on top.
U would replace the 16 ohm resistor with the 18 ohm. Remove the 220 ohm & 120 resistors & their jumper pins.
Now u will want to use the trim pot as a variable resistor rather than a divider so u will connect the (variable) center leg to one of the end legs. Use ur multimeter to work out which one to connect it to, so that u know when u turn the screw u know whether ur making the resistot bigger or smaller (with regard to the way that u r turning the screw).
The trim pot cam go on the board where one pair of jumper pins were with the 51 ohm resistor then connecting the trim pot to the cathode of the SCR (where the 220 or 120 ohm WAS, depending on which spot u use).
So now, with the trim pot at its full value of 250 ohms the initial firing point will be slightly ADVANCED of the most advanced setting (no jumpers on the 220 or 120 ohm resistors) previously available. (basicly increases the 16 ohm to 16.984 ohms).
With the trim pot at its smallest value of zero ohms, the initial firing point will be roufhly the same as if u had a jumper on both the 220 & 120 ohm resistors. (basicly decreases the 16 ohm to 13.304 ohms).
To read the value of the trim pot once u have found ur ideal setting, u will first need to remove it from the circuit.
To then make uo a resistor of the same value u can put resistors in series, which adds their values together, or in parallel (use an online calculator to make it easy, google parallel resistor calculator), or a combination of series/parallel to get the value u need if it isnt available.
I think I'd be inclined to try leaving the minature trim pot in circuit before making up a fixed value resistor as I really think it might handle the vibration. When u see how they're constructed u'll see wot I mean.
So hopefully u can all understand my description of wot u need to do. If not, give me a yell asking about wot u dont understand & we'll try & clear it up.
With regard to the timing cap for use with a high reving race type motor, I think that changing from a 4.7uf to a 3.3uf will be enough of a reduction to allow the kind of revs needed for a race motor but this isnt something I have tested. My motor is ported & tuned for a wide midrange power band for use with a shift kit & 8 speed cassette, so my CDI is set up with just a smidge more initial advance & just a tad steeper retard curve (small extra capacitance), to keep it on the pipe which has slightly longer header.
By the way, nice job on the key lock ignition there KCVale, nice looking bike also, wot we can see of. The 3 position switch for the timing caps isnt a bad idea either, for a daily ride type aplication. For a race type motor I think I'd first tune the CDI to suit the motor's requirements, then solder all components in properly, just to ensure nothing could go wrong.
Cheers