CD ignition repair

[thevojtiseks]

Does anybody know if its possible to get the CD ignition unit repaired - where and rough cost ?? Mine seems to have stopped whistling !!

1971 911S.

Thanks !

[Groesbeck Hurricane]

Do a search on the Bosch CD. There are some photos imbedded in several recent topics that show the innards and give suggestions on where to look for damage/wear.

[campbellcj]

Your cheapest bet (and it IS a bet to some degree) is to find a used one for $100-200.

Keep a spare...BTDT and a spare box saved me from a very short day at the track.

[Lorenfb]

Pelican has many sources for rebuilt parts. Since you use their BBS, why not
ask the Pelican salesmen?

Suggesting another parts house? I don't think they have a Porsche BBS.
Where's your loyality?

[jdowty3]

Wayne does sell a rebuilt unit but the $350 price tag seems a bit steep compared to other sources.

[thevojtiseks]

I didn't realize Pelican does rebuilt parts - I did check out the online cataloge and only saw new - non OEM parts for sale, and I'm trying to keep my car original. Thanks for the tip though

[Gunter]

I believe that you have the 3-pin Bosch CD module. Advertise on this board under WTB classifieds. $100.00 should do it. Keep a spare.

[jdowty3]

Did you do an engine swap or add a CDI to your 71 motor? Have you tried replacing the relay yet? I just read a post where someone described why/where the relays fail, a possible fix, and a prevention tip.

[Early_S_Man]

thevo ...

Generally, repair is in the $100 range ...

Here is the link to the thread with pics, shematic, and parts list ... also Bosch test procedure and general circuit theory of operation for the Bosch BHKZ -- aka CDI unit!

Perma-tune CD or Bosch CD?

When the whistling stops ... it is usually the 2N3055 power transistor ... currently the most popular replacement transistor in the world ... $1 - $5 available from many, many electronic surplus and supply stores.

[Wayne 962]

Here's the link to the rebuilt units:

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

and they come with a full warranty as well.

-Wayne

[Lorenfb]

"When the whistling stops ... it is usually the 2N3055 power transistor ... currently the most popular replacement transistor in the world ... $1 - $5 available from many, many electronic surplus and supply stores."

or the following:

1. bad solder connections
2. shorted input zener diode
3. shorted SCR
4. shorted rectifier diodes
5. bad flyback transformer
6. shorted flyback zener diode
7. shorted base diode
8. etc.

Also, the 2N3055 is NOT a good replacement as it lacks the adequate SOA
(safe operating area) for the switching current of the oscillator.

Kinda like; It uses oil, so put those rubber things (get em @ Pep Boys)
on the valve ends.

[thevojtiseks]

Originally posted by Lorenfb
"
Also, the 2N3055 is NOT a good replacement as it lacks the adequate SOA
(safe operating area) for the switching current of the oscillator.

What would you recomend this is replaced with ??

Thanks !

[thevojtiseks]

Originally posted by Wayne at Pelican Parts
Here's the link to the rebuilt units:

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

and they come with a full warranty as well.

-Wayne

Thanks Wayne, but I have a '71 and you don't have a part for this year listed...

[Lorenfb]

There's only two types; a 3 pin and a 6 pin. The Pelican catalog shows them both!
Unless you don't have a Bosch original.

[thevojtiseks]

Pretty sure I have a Bosch original, it's just the online catalogue does not list anything prior to 1974 ....I had assumed somthing changed and this is why you don't have units for the 71 model.....anyway what would you recomend using instead of the 2N3055 transistor Lorenfb ?

[Early_S_Man]

thevo ... the 3-pin CDI is the same unit for all 1969 thru 1977 model cars!

The 2N3055 has worked for 30+ years in many CDI units, so dismissing that as a reasonable replacement is a bit self-serving of Loren! It is still used in more current power supply designs than any other transistor in the world! There have been many, many new Silicon power transistors introduced in the past 40 years, but none have replaced the 2N3055 in massive numbers ... it remains in production today because it is a very useful and reliable product!

Many folks on this board have repaired their own CDI, and suggesting that a reliable unit requires replacement of the 2N3055 with a different transistor for it to be a reliable repair is pure BS! The analogy he used is LAME, and he knows it!

Loren's repair service costs $275 on an exchange basis ... through Pelican. I will let Pelicanheads make up their own mind as to whether it is worth that much $$$ to them!

[Lorenfb]

"Many folks on this board have repaired their own CDI, and suggesting that a reliable unit requires replacement of the 2N3055 with a different transistor for it to be a reliable repair is pure BS!"

First, that part RARELY every fails. So, why direct DIYs to replace O.K. parts.
Second, Bosch never used the standard 2N3055. Just because it fits and has
some similiar characteristics, doesn't mean it should be used as a replacement.
It's like using VW engine parts in a 912 engine because they're both 4 cylinder
engines and look similiar.

[Randy Webb]

yeh - build that business....

[Early_S_Man]

Loren,

You are losing credibility with every post and by the minute! First you say the 2N3055 is underated, and imply that to use that part would be an unreliable repair ... then you say that part rarely fails!

If Bosch never used the 2N3055 in production ...why is it listed in their spare parts document?

I have seen it used in dozens of CDI units that had never been apart or repaired previously ... and pics Zendalar posted from Finland clearly shows an RCA 2N3055 in his CDI unit! His unit was old and had many fractured wires ... a very likely problem with most 3-pin CDI units, which are 27 - 35 years old -- if still original!

[Lorenfb]

Bottomline: Find the spec for the RCA 2N3055 35+ years ago and compare
it to the 2N3055 to can buy now. RCA had a much greater SOA. If they're
the same spec (which they're not), then use it.

As I said, who knows whether that's even the problem. This is a complete waste of time!