xantia Transistors

uhn113x · Unread post by **uhn113x** » 09 Feb 2007, 07:34

Crystal, Kenny! I read everything absolutely literally, so one syllable or less is A Good Thing.

At a guess, Cit would use some obscure devices here; espacially as the use PNP - more expensive than the usual NPN transistors that the circuit could be designed around easily.

Hope you sort it out.

Unread post by **KennyW** » 09 Feb 2007, 14:05

Hi Mike and Peter,

Here are the details of the transistors on my new one.

FW26025A1
9M755
9M 604
MYS

The logo at the top is ST.

Have taken some photo's of the damaged Darlington Transistors.

Will check transistors with multi-meter soon and get back to you all,

Cheers

Kenny

uhn113x · Unread post by **uhn113x** » 09 Feb 2007, 15:05

Kenny
Looks like the FW26025 is available
http://www.1sourcecomponents.com/partinfo/FW26025.htm but the MJ11015 as Peter's suggestion is a direct equivalent.

Trust them to use a weird transistor, rather than a cheap and common NPN !

Clogzz · Unread post by **Clogzz** » 09 Feb 2007, 15:49

FW26025 has been used since the CX, and was supposedly ‘unavailable’,

as if Citroën had taken the lot of them:

http://img150.imageshack.us/img150/9959/regul8jp.jpg

AndersDK · Unread post by **AndersDK** » 09 Feb 2007, 15:51

uhn113x wrote:Kenny
Looks like the FW26025 is available
http://www.1sourcecomponents.com/partinfo/FW26025.htm but the MJ11015 as Peter's suggestion is a direct equivalent.

Trust them to use a weird transistor, rather than a cheap and common NPN !

Any major company in need of large quantities specifies their own transistor - and will have it delivered to spec at a reduced discount price - with some odd type number. This odd type number is referring to the spec of the silicon dice making up the transistor.

The "standard" type numbers we all know off - are the suppliers standard off the shelf types, having one major advantage : no lead time for delivery in smaller quantities.

ST will be SGS-Thompson, which is one of the worlds largest silicon dice suppliers.

BTW : it will not be Citroen that supplies or specifies the transistor, but the manufacturer of the blower assembly, probably Valeo or Bosch - or in turn one of their module suppliers.

uhn113x · Unread post by **uhn113x** » 09 Feb 2007, 17:14

Right - now I have seen one (thanks, Clogzz) I can see why 'they' used this; the heatsink (collector) goes to chassis, hence PNP, and it is a Darlington because there is not really room for any more electronics.
As to rivetting it on ......

However, the design (and that of the CX) will surely have cost more, especially if the transistor had to be produced; insulating the heatsink and using a common NPN device would have been cheaper; that was really what I was getting at.

As to "them" I meant anyone that designed this fiendish device!

Mike - in electronics professionally including design in my previous life 1961-1980

Unread post by **KennyW** » 09 Feb 2007, 18:11

Hi Peter,Mike and Clogzz,

I just wanted to fix my heater blower not start a debate

, but hope the info on this thread will help anybody else.

Still trying to figure how I attach the photo's to the Forum!!!!!!!!!!!!!!!!!!

Cheers

Kenny

Unread post by **Peter.N.** » 09 Feb 2007, 23:24

Sorry, I missed most of this. I replaced mine with ordinary straight PNP transistors and it worked a treat!

AndersDK · Unread post by **AndersDK** » 10 Feb 2007, 00:51

Peter.N. wrote:Sorry, I missed most of this. I replaced mine with ordinary straight PNP transistors and it worked a treat!

Which is the sensible approach

Anders - in electronics professionally including back engineering in my previous life 1973-1998

uhn113x · Unread post by **uhn113x** » 10 Feb 2007, 08:32

Anders & Peter
Absolutely!

This electrickery will never catch on ... (W Gummidge)

Kenny
It is always good to question things - by that we learn. I don't have a Xant or CX, but I now know how the blower speed works and what can be done if there is a problem; that may be no use to me, but I may be able to help someone else.

Photos - you just need to put them somewhere we can see them (not on your PC)
Use something like www.flickr.com - it's free!
Then, you need a pair of IMG and /IMG tags (surrounded by [] )with the URL between them.
Have a look at this by doing a quote on it and you will see how I have made it.

Unread post by **KennyW** » 10 Feb 2007, 09:16

Hi Mike , Peter and Clogzz,

Thanks for all the help, one last question the transistor with the brown heat is that still usable.

I read my manual for the multimeter and it talks about putting the base and emitter pins into the meter to check whether it is working.

Problem the pins are too far apart and I don't which is which or it may be irrelevant.

Cheers

Kenny

uhn113x · Unread post by **uhn113x** » 10 Feb 2007, 14:25

Hi Kenny

KennyW wrote:Hi Mike , Peter and Clogzz,

Thanks for all the help, one last question the transistor with the brown heat; is that still usable?

Oh? I think is is safe to say that if it has got so hot that it has gone brown, then it is consigned to the big electronics factory in the sky! Bung a new one in.
(edited to insert missing question - please ignore "Oh?"

)

I read my manual for the multimeter and it talks about putting the base and emitter pins into the meter to check whether it is working.

Problem the pins are too far apart and I don't which is which or it may be irrelevant.

Cheers

Kenny

Right, is is probably a digital meter with a transistor tester on it - right? I have a few of them here, but they may not work on a transistor like this, as it is really two transistors in the one case. A Darlington.
Better just to test it on resistance or ohms range, using the normal leads.

Looking at the device laid on its front with pins nearest the bottom and right-to-left, emitter is on left, base on right. The collector is the case.
That arrangement is called TO3.
Connect each of the three pairs of leads in turn, in both directions.
You should get the following:
The actual values read are not important and depend on the meter.
B & E - no reading
E & B - reading
B & C - no reading
C & B - reading
E & C - no reading
C & E - no reading.
Your transistor is probably short circuit and will show readings from C to E either way, and maybe everywhere else!

HTH

MikeT · Unread post by **MikeT** » 04 Jul 2007, 17:14

uhn113x wrote:Hi Kenny
Better just to test it on resistance or ohms range, using the normal leads.

Looking at the device laid on its front with pins nearest the bottom and right-to-left, emitter is on left, base on right. The collector is the case.
That arrangement is called TO3.
Connect each of the three pairs of leads in turn, in both directions.
You should get the following:
The actual values read are not important and depend on the meter.
B & E - no reading
E & B - reading
B & C - no reading
C & B - reading
E & C - no reading
C & E - no reading.
Your transistor is probably short circuit and will show readings from C to E either way, and maybe everywhere else!

HTH

I followed the above and get readings both ways between Collector and Emitters on both transistors, i.e.

B & E - no reading
E & B - reading
B & C - no reading
C & B - reading
E & C - reading
C & E - reading

Can someone re-confirm I need to replace both transistors before I get the drill out? Is it usual for them both to fail the same?

Thanks,
Mike

uhn113x · Unread post by **uhn113x** » 04 Jul 2007, 17:24

Hi Mike
Assuming that the readings from C to E in both directions are, say, less than 2 kohms, they have gone short-circuit.

Possibly the reason for both to fail is that there was a "spike" on the supply - maybe welding, maybe a while ago, or the battery (alternator) voltage went sky-high at some point - one way to do that is by disconnecting the battery with the engine running, not necessarily by you.

HTH

MikeT · Unread post by **MikeT** » 04 Jul 2007, 17:32

Hi uhn113x,

I compared them to the new transistors and can confirm the old ones have gone short-circuit C-E.

In my case, the failure happened in my custody and, similar to citrojim's failure, water leaking onto the blower may have caused the short.

Thanks,
Mike

French Car Forum

xantia Transistors

CBE!