Cd Box

[sixbanger]

Is there a way to test a three pin CD box.Mine I think shot craps today.The car started and ran then died.Tried to restart it and it seemed like it was out of gas.Put gas in no go.Then I open the lit and had somone crank it and no sound comming from the box.
I took my meter and I found 12V at the plug going into the box.

THX
RT.

[azasadny]

Do you have the Bosch CD unit or the PermaTune? I know that PermaTune has test and diagnostic info on their website, but I'm sure about Bosch. Do a search here and I'm sure you'll find what you need. Good luck!

[limble]

I've heard from experts that the only way is to put it in a car that has a CD unit you are sure is working. Meaning, I couldn't find anyone who could tell me how to bench test it. If You find a way to do that send me a PM. I have a unit I think is faulty so I just wired around it with a stock coil and a condenser so I could get it going again. The car is my 70 which is in the middle of a major overhaul but someday I'm going to have to deal with it. If you haven't checked out the priceof a stock CD the prices are outrageous.

What year is your car?

[Jay Auskin]

There may be 12V going into the box, but what's coming out?? I believe you need to check the input to the coil. I think the Haynes manual even has a test instruction for this?? I'd have to check. But, the box should "buzz".

[Lorenfb]

"If you haven't checked out the priceof a stock CD the prices are outrageous."

Not true! Pelican sells rebuilt Bosch units at reasonable prices.

Tests for 3 pin Bosch:

1. Check for +12 at center pin. Unit should buzz with power.
CDI case should be ground.
2. Use a test light connected to +12 to check for good grounding
distributor points. Light should flash when cranking.
3. Pull coil wire from distributor & check spark (25mm spark to ground).
4. Check connections to coil; CDI to one pin & ground on the other pin.
5. Use a test coil if no spark in test #3.
6. If all the above & no spark find a test CDI.

The above procedure can be used for bench testing:

1. ground one coil pin to CDI case
2. CDI power pins: +12 to center pin, ground to CDI case (unit will buzz)
3. CDI output to other coil pin
4. coil wire from coil set at 10mm from CDI case
5. ground & remove points connection to CDI case for each coil spark

[Zeke]

This just in from a coversation at the LAAllEuroSwap (or whatever it is called). There is a way to BYPASS the CDI and run off the points and coil only.

Maybe a search will turn that up as I certainly don't know how to do it. Everyone should have these instructions in their glove box for emergencies. Apparently, all it takes is a made up jumper.

Anyone?

[limble]

Loren,

I can't find the rebuilt Bosch unit on the Pelican site. If you can find it I'd like to have the link. I've had T owners looking for one. I was talking about a new stock unit price.

Also, I'm a mechanical guy and can't understand your directions. Do you have an unabridged set with a schematic that I can use? I need to check my CDI box.


Thanks,

[rob'smobile]

me too I 'm not following please post pick and simlify ???

[Lorenfb]

You just have to look!

www.pelicanparts.com/catalog/shopcart/911M/POR_911M_igniti_pg6.htm#item27

There's nothing as simple as hooking-up & testing a Bosch 3 pin CDI.

1. 2 power wires - +12 & ground
2. 2 coil wires - 1 ground & 1 to the CDI
3. 1 pickup wire to the points which opens & closes to ground

[sixbanger]

Yes I know how to bypass the CD box and make it run.I like the explanation in above post.The coil has two wire connector pins on top.so out of the box to the pos side of the coil and the other side to groung RIGHT. Test wire is the one to the points.

[limble]

Originally posted by limble
The car is my 70 which is in the middle of a major overhaul but someday I'm going to have to deal with it. If you haven't checked out the priceof a stock CD the prices are outrageous.

What year is your car?

Loren,

I did "look".
The link you sent is for a 74+ I found those.

[Jim Williams]

Mike,

I believe all the 3-pins are the same. They all worked from a set of points up through '77. IIRC, the 6-pins used a reluctor starting with the SC in '78.

[Early_S_Man]

RT,

Here are threads with troubleshooting info:

Perma-tune CD or Bosch CD?

BOSCH CDI discrete components troubleshooting

All '69 thru '77 models use the same CDI unit, Bosch 0.227.200.001 ...

[Lorenfb]

"I believe all the 3-pins are the same. They all worked from a set of points up through '77. IIRC, the 6-pins used a reluctor starting with the SC in '78."

That's correct. Pelican needs to fix their catalog.

"Yes I know how to bypass the CD box and make it run.I like the explanation in above post.The coil has two wire connector pins on top.so out of the box to the pos side of the coil and the other side to groung RIGHT. Test wire is the one to the points."

It's that simple!

To produce a spark from a 6 pin Bosch CDI, connect basically as in the
3 - pin case. Then use a 1.5 volt "AA" with the negative connected to
pin 7 (center lead of green wire) and the "+" touched to the CDI case to
produce a spark. The distributor pickup needs to be disconnected,
if this test is done with the unit hooked-up in the car.

Check out this web site (www.systemsc.com) on the Diagnostics page
for ignition coil data and distributor pickup specs. The Waveforms page
provides info on the pickup signal and the high voltage coil signal on the
Bosch CDI.

[Jim Williams]

Loren,

Thanks for posting all this good info about the CDI boxes. I'll book mark the link to the troubleshooting threads. I have a file folder in my "Porsche" file cabinet with schematics I made of the electronics in these boxes several years back, but I never carried it as far as the detail you posted.

[Early_S_Man]

I am not sure what you guys find so 'useful' about Loren's diagnostic page with regards to a 3-pin CDI 'box' [or where you found it] ... as it refers to multiple technology ignition systems on the same page without any form of outline or headings, but the info posted for both windings of the CDI coil is incorrect!

The Bosch test document I posted on the 'Bosch Permatune' thread link above has the correct coil info [as does the Haynes manual] for checking the resistance of the coil windings ... and would be worth saving and printing for reference.

[Jim Williams]

Warren,

Ooops, my bad. The threads you posted links to in your message dated 02-07-2005 3:43 AM are the ones I intended to give credit to. I am still new at this Pelican BBS, and looked at the wrong message when I posted my reply. Just take away Loren's name from my post and replace it wiith yours, that was the way I intended it. I have both these threads bookmarked.

My apologies. (No offense intended to Loren).

[Lorenfb]

"but the info posted for both windings of the CDI coil is incorrect!" - Warren -

Wrong again Warren! Just can't get it right as usual.
Get the multimeter out, as my data comes from actual Bosch Porsche coils and
NOT antiquated data.

Some people just search for data and post it without any understanding
of it or how to interpret it. Kinda like internet spam.

[Early_S_Man]

Loren,

You REALLY should get your multimeter calibrated!!! Your data is erroneous, and calling the data from official Bosch documents, as well as the Porsche factory service manuals antiquated ... DOESN'T make it so! Copper wire doesn't change its' resistance over the years ... just because YOU say the specs are invalid! Your data doesn't even specify limits or a tolerance ...

I have tested several non-leaking German-made Bosch 0.221.121.001 and 0.221.121.006 coils over the years and always found them to be nominally within the factory specs of 0.4 - 0.6 Ohms for the primary, and 650 - 790 Ohms for the secondary.

As far as spamming this board goes ... take a long look in the mirror, for that is what 90% of your posts have been since the day you joined this board!!! Rather than post useful info or answers, you always post the link to your website ... which contains NO useful information at all regarding Bosch CDI systems!

Just to illustrate some of the 'noise' you have added to CDI threads ...

1. You have stated/posted categorically that the inverter transistor Bosch used for both 3-pin and 6-pin CDI units wasn't a 2N3055! That statement contradicts Bosch documentation, and my experience examining both types of CDI!

2. You have stated/posted that the 2N3055 transistors don't have sufficient SOA [Safe Operating Area] ... for the Bosch inverter design!

3. You have stated/posted that the 2N3055 transistors seldom fail in Bosch CDI units, contradicting both of the above statements!

4. You have stated/posted that currently-available 2N3055 transistors don't have the same specs as original RCA 2N3055 transistors!

5. You have stated/posted that testing individual components of a CDI unit with a multimeter is not an effective method of troubleshooting and repair ... in an attempt to discourage or discount DIY repair!

[Lorenfb]

1. You have stated/posted categorically that the inverter transistor Bosch used for both 3-pin and 6-pin CDI units wasn't a 2N3055!

No Bosch CDI unit has generic 2N3055s other than RCA ones.
I worked for Motorola Semiconductor for many years and know the products
of many/all of the semiconductor suppliers. The RCA 2N3055 had a higher
SOA than generic 2N3055s.

2. You have stated/posted that the 2N3055 transistors don't have sufficient SOA [Safe Operating Area] ... for the Bosch inverter design!

True! The generic 2N3055 lacks the SOA. Check the max voltage & current switched. They exceed the generic 2N3055 ratings.

4. You have stated/posted that currently-available 2N3055 transistors don't have the same specs as original RCA 2N3055 transistors!

The RCA 2N3055 had a higher SOA than the generic 2N3055. One MUST
always obtain a data sheet of replacement semiconductors to determine
adequate and proper ratings, especially in inductive switching applications
where secondary breakdown can destroy semiconductors.

5. You have stated/posted that testing individual components of a CDI unit with a multimeter is not an effective method of troubleshooting and repair ... in an attempt to discourage or discount DIY repair!

Proper component testing requires removal from the circuit board. Dynamic testing
is the most effective method of troubleshooting, i.e. for any electronic system with
greater than a few components, e.g. many components are affected by the circuit
voltages which CAN'T be tested for outside of a circuit.

CDI boxes are very simple to troubleshoot using an o-scope.

Again, reading tech pubilcations without fully understanding electronics
can be very problematic for DIY repairs.

Bottomline: Topic is a waste of time anyway, since the power transistor
rarely if ever fails in the original Bosch CDI. As I said, use an o-scope for
testing a CDI unit and NOT a limited multimeter.