Blower Transistors
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Blower Transistors
Yesterday morning on my way to work I suffered the infamous failure of the blower motor control transistors and had an uncontrollable hurricane blowing through the car
I had a look, and sure enough, one was emitter-collector short circuit. What was more interesting is that my car had a long-standing windscreen leak in the usual place and the blower motor and controller had spent some time being rather damp. There was ample evidence of corrosion on the heatsink and PCB.
Wether or not this led to the failure or not is a moot point but it was not helping. I also noticed that Valeo had been very mean with heatsink compound when fitting the transistors originally.
Mine had the FW26025A type transistors, for which information is very hard to come by. They do however have equivilents in the MJ11015 and the 2N6287.
I have some on order from Farnell but I have had to buy six to meet the £20 minimum order conditions they impose Not many places seem to stock them and strangely, the consumer side of Farnell, CPC, don't, even though they're the same company Farnell have hundreds in stock.
So, if anyone wants a pair or two, let me know and you can have them at cost. As it's a bit of a tricky job fitting them (drilling out rivets etc), I'll be quite happy to fit them for you as well FOC.
I would suggest, if you have had a windscreen leak in the past, your blower may soon go into hurricane-mode and the transistors will need replacing. Use plenty of heatsink compound when you do! It may be a good idea to pre-empt their failure by changing them early. Having either a hurricane or nothing in a car on a day like today is no fun
A bit of trivia: These transistors are designed for use in high power audio amplifiers and thankfully not specifically for Citroen blower motor control
I had a look, and sure enough, one was emitter-collector short circuit. What was more interesting is that my car had a long-standing windscreen leak in the usual place and the blower motor and controller had spent some time being rather damp. There was ample evidence of corrosion on the heatsink and PCB.
Wether or not this led to the failure or not is a moot point but it was not helping. I also noticed that Valeo had been very mean with heatsink compound when fitting the transistors originally.
Mine had the FW26025A type transistors, for which information is very hard to come by. They do however have equivilents in the MJ11015 and the 2N6287.
I have some on order from Farnell but I have had to buy six to meet the £20 minimum order conditions they impose Not many places seem to stock them and strangely, the consumer side of Farnell, CPC, don't, even though they're the same company Farnell have hundreds in stock.
So, if anyone wants a pair or two, let me know and you can have them at cost. As it's a bit of a tricky job fitting them (drilling out rivets etc), I'll be quite happy to fit them for you as well FOC.
I would suggest, if you have had a windscreen leak in the past, your blower may soon go into hurricane-mode and the transistors will need replacing. Use plenty of heatsink compound when you do! It may be a good idea to pre-empt their failure by changing them early. Having either a hurricane or nothing in a car on a day like today is no fun
A bit of trivia: These transistors are designed for use in high power audio amplifiers and thankfully not specifically for Citroen blower motor control
Jim
Runner, cyclist, time triallist, duathlete, Citroen AX fan and the CCC Citroenian 'From A to Z' Columnist...
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Hi Jim
Good detection work. I believe that the original transistors are darlington pairs, but I have always used standard PNP transistors and they have worked OK. There were a while ago, lots of people having this trouble (hence my signature) so I would have thought you would have some takers.
Most of the component suppliers have either almalgamated or dissapeared now. I retired from the TV trade about 3 years ago and that's also now almost completely dissapeared.
Good detection work. I believe that the original transistors are darlington pairs, but I have always used standard PNP transistors and they have worked OK. There were a while ago, lots of people having this trouble (hence my signature) so I would have thought you would have some takers.
Most of the component suppliers have either almalgamated or dissapeared now. I retired from the TV trade about 3 years ago and that's also now almost completely dissapeared.
Jim -
Dont get wrong on the heatsink compund. Its only used to make the transistor to heatsink heat transfer as even and effective as possible. Its not as good as pure aluminium in heattransfer. Therefore adding a layer of compound may very well worsen the matter.
Thats the reason why Valeo only used a smear of it.
Dont get wrong on the heatsink compund. Its only used to make the transistor to heatsink heat transfer as even and effective as possible. Its not as good as pure aluminium in heattransfer. Therefore adding a layer of compound may very well worsen the matter.
Thats the reason why Valeo only used a smear of it.
Anders (DK) - '90 BX16Image
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Thanks Anders,
A very valid point indeed. Too much is worse than too little in this case
Basically, if when mounting the transistor on its heatsink the compound squeezes itself out from under the transistor and becomes visible around it as a bead you've used far too much
The line between too little and too much is a very fine one as we have discovered in the past with Intel P4 CPU chips. This is such a problem now that replacement chips and heatsinks come with a little syringe containing exactly the right amount of compound.
Peter, I began my career as a TV Service Engineer but could not fix one to save my life nowadays. I too miss the days when every town had a shop where you could get all the electronic bits you needed, especially to fix the radio or telly. Now we have Maplin in a few towns but it's a very poor substitute. All I can say is thank goodness for the Internet.
I'm off up to the National Vintage Communications Fair near Warwick tomorrow with a pal. We were going in the Activa but when I told him the aircon and ventilation was non-functional in it, he elected to take us in his Picasso
A very valid point indeed. Too much is worse than too little in this case
Basically, if when mounting the transistor on its heatsink the compound squeezes itself out from under the transistor and becomes visible around it as a bead you've used far too much
The line between too little and too much is a very fine one as we have discovered in the past with Intel P4 CPU chips. This is such a problem now that replacement chips and heatsinks come with a little syringe containing exactly the right amount of compound.
Peter, I began my career as a TV Service Engineer but could not fix one to save my life nowadays. I too miss the days when every town had a shop where you could get all the electronic bits you needed, especially to fix the radio or telly. Now we have Maplin in a few towns but it's a very poor substitute. All I can say is thank goodness for the Internet.
I'm off up to the National Vintage Communications Fair near Warwick tomorrow with a pal. We were going in the Activa but when I told him the aircon and ventilation was non-functional in it, he elected to take us in his Picasso
Jim
Runner, cyclist, time triallist, duathlete, Citroen AX fan and the CCC Citroenian 'From A to Z' Columnist...
Runner, cyclist, time triallist, duathlete, Citroen AX fan and the CCC Citroenian 'From A to Z' Columnist...
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My new transistors arrived at 7 this morning courtesy of the Postman. Not bad considering Farnell did not get the order until 17:10 on Friday evening. I'm mighty impressed with both companies A half-hour before work saw it all back in and working
One thing I noticed as I was reassembling was that the spade connectors on the loom and motor wiring were a rather loose fit. The responded nicely to a gentle crimp to tighten them up. Considering the currents that run around these wires, a bit of high resistance could cause overheating and more bother in the long run.
I found another possible substitute to the MJ11015 today, the MJ11033. It can run 50A of collector curent (20A for the MJ11015) but it is obsolete and the small stock I could find costs nearly £16 per transistor
One thing I noticed as I was reassembling was that the spade connectors on the loom and motor wiring were a rather loose fit. The responded nicely to a gentle crimp to tighten them up. Considering the currents that run around these wires, a bit of high resistance could cause overheating and more bother in the long run.
I found another possible substitute to the MJ11015 today, the MJ11033. It can run 50A of collector curent (20A for the MJ11015) but it is obsolete and the small stock I could find costs nearly £16 per transistor
Jim
Runner, cyclist, time triallist, duathlete, Citroen AX fan and the CCC Citroenian 'From A to Z' Columnist...
Runner, cyclist, time triallist, duathlete, Citroen AX fan and the CCC Citroenian 'From A to Z' Columnist...
The fan in my car STOPPED completely due to those spade connectors on the blower motor itself. After unplugging them and plugging them back in again it was working, but the terminals were getting quite hot.citrojim wrote: One thing I noticed as I was reassembling was that the spade connectors on the loom and motor wiring were a rather loose fit. The responded nicely to a gentle crimp to tighten them up. Considering the currents that run around these wires, a bit of high resistance could cause overheating and more bother in the long run.
In the finish I ended up soldering the crimps in the terminals (especially on the brown plug) tensioning the terminals a bit (they were all loose) and also cleaning them with some LPS1.... no more hot terminals!
Regards,
Simon
Simon
1997 Xantia S1 3.0 V6 Auto Exclusive in Silex Grey
2016 Nissan Leaf Tekna 30kWh in White
2011 Peugeot Ion Full Electric in Silver
1977 G Special 1129cc LHD
1978 CX 2400
1997 Xantia S1 2.0i Auto VSX
1998 Xantia S2 3.0 V6 Auto Exclusive
1997 Xantia S1 3.0 V6 Auto Exclusive in Silex Grey
2016 Nissan Leaf Tekna 30kWh in White
2011 Peugeot Ion Full Electric in Silver
1977 G Special 1129cc LHD
1978 CX 2400
1997 Xantia S1 2.0i Auto VSX
1998 Xantia S2 3.0 V6 Auto Exclusive
A transistor configuration using two transistors of opposite type (NPN and PNP) is the Sziklai pair, sometimes called the "complementary Darlington". So, PNPs would constitue a pseudo Darlington pair OK.
In reality, the appelation 'Darlington pair' is correct only when on a single chip.
In reality, the appelation 'Darlington pair' is correct only when on a single chip.
Good detection work. I believe that the original transistors are darlington pairs, but I have always used standard PNP transistors and they have worked OK. There were a while ago, lots of people having this trouble (hence my signature) so I would have thought you would have some takers.
R.I.P. January 2010.
XM 2.1 auto VSX 1996 - Bosch Inj, Xantia HDi 90 estate 1999, Xantia 1.9TD 1997
Previously...
GS 1970, Dyane 1974, Xantia 94 VSX TD, XM 94, 2.1 auto - Lucas Inj, XM 92 2.1 estate - Lucas Inj
XM 2.1 auto VSX 1996 - Bosch Inj, Xantia HDi 90 estate 1999, Xantia 1.9TD 1997
Previously...
GS 1970, Dyane 1974, Xantia 94 VSX TD, XM 94, 2.1 auto - Lucas Inj, XM 92 2.1 estate - Lucas Inj
Truth is that there is precious little left to repair on a 'modern' TV, other than the PSU/scan modules. I install UK SAT/TV in Provence, and over the last 15 years I have seen the virtual disappearance of repairable kit - be it TVs or satellite receivers. Textronix oscilloscope just sits on the bench these days...Peter, I began my career as a TV Service Engineer but could not fix one to save my life nowadays. I too miss the days when every town had a shop where you could get all the electronic bits you needed, especially to fix the radio or telly. Now we have Maplin in a few towns but it's a very poor substitute. All I can say is thank goodness for the Internet.
R.I.P. January 2010.
XM 2.1 auto VSX 1996 - Bosch Inj, Xantia HDi 90 estate 1999, Xantia 1.9TD 1997
Previously...
GS 1970, Dyane 1974, Xantia 94 VSX TD, XM 94, 2.1 auto - Lucas Inj, XM 92 2.1 estate - Lucas Inj
XM 2.1 auto VSX 1996 - Bosch Inj, Xantia HDi 90 estate 1999, Xantia 1.9TD 1997
Previously...
GS 1970, Dyane 1974, Xantia 94 VSX TD, XM 94, 2.1 auto - Lucas Inj, XM 92 2.1 estate - Lucas Inj
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In the past: 3, CX td Safaris and about 7, XM td estates. Lovely cars. - x 1199
Hi Lol
The MJ 11015's are shown as as a pair of like polarised transistors in the data but I had replaced at least two pairs with ordinary bi polar transistors before this was brought to my attention and they worked fine, so - I dont know.
I still get the odd TV in for repair but most of the little work I get now is setting up TV/video bundles that have defeated their puchasers. I do though have a TV in my workshop at present, which has only served to remind me of how useless is all the equipment I have. I used my EHT meter to see if the line was starting up, will probably be the last time I ever use it!
The MJ 11015's are shown as as a pair of like polarised transistors in the data but I had replaced at least two pairs with ordinary bi polar transistors before this was brought to my attention and they worked fine, so - I dont know.
I still get the odd TV in for repair but most of the little work I get now is setting up TV/video bundles that have defeated their puchasers. I do though have a TV in my workshop at present, which has only served to remind me of how useless is all the equipment I have. I used my EHT meter to see if the line was starting up, will probably be the last time I ever use it!
Forgive me if I'm teaching Granny to suck eggs....
I've never got around to looking at the blower motor circuitry as yet, so I'm not sure what drives the blower motor output transistors.
Regarding the Darlington vs non-Darlington, it really depends what is driving the transistors. The non-Darlingtons will require more drive. If the drive circuitry can supply the necessary current, then it will also be required to sink more current, and dissipate more power (heat). The MJ11015 have a current gain of up to 1000. Non-Darlingtons of similar rating would usually have a current gain of less than 100 - probably less than 50. Current gains of the order of 1000 from a single stage are very much the domain of small signal transistors.
I've never got around to looking at the blower motor circuitry as yet, so I'm not sure what drives the blower motor output transistors.
Regarding the Darlington vs non-Darlington, it really depends what is driving the transistors. The non-Darlingtons will require more drive. If the drive circuitry can supply the necessary current, then it will also be required to sink more current, and dissipate more power (heat). The MJ11015 have a current gain of up to 1000. Non-Darlingtons of similar rating would usually have a current gain of less than 100 - probably less than 50. Current gains of the order of 1000 from a single stage are very much the domain of small signal transistors.
Re: Blower Transistors
Jim, do you have any of the transistors left? If so then I will take a pair off your hands.citrojim wrote:So, if anyone wants a pair or two, let me know and you can have them at cost. As it's a bit of a tricky job fitting them (drilling out rivets etc), I'll be quite happy to fit them for you as well FOC.
Richard
1998 Xantia 1.9TD Estate (Sold - replaced with Skoda Octavia (sorry))
Re: Blower Transistors
This just happened to mine , is it an easy fix as i'm not electrically mindedcitrojim wrote:Yesterday morning on my way to work I suffered the infamous failure of the blower motor control transistors and had an uncontrollable hurricane blowing through the car
Anybody in the Lancs region are welcomed to fix it
2013 Berlingo Multispace 1.6 XTR 115bhp
2003 2:0 HDI Dispatch Van 186000 miles......gone
2000 Xantia Hdi 90bhp Forte Estate 97000 miles gone..........to heaven
New High pressure Fuel Pump and Patched ECU , Blower Module fixed by CitroJim
2003 2:0 HDI Dispatch Van 186000 miles......gone
2000 Xantia Hdi 90bhp Forte Estate 97000 miles gone..........to heaven
New High pressure Fuel Pump and Patched ECU , Blower Module fixed by CitroJim
- CitroJim
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Re: Blower Transistors
No, but you're welcome to send me your blower module and I'll fix it for you and return it. I have a stock of spare transistors PM me if you want to take me up on thispikecrazy wrote:This just happened to mine , is it an easy fix as i'm not electrically minded
Anybody in the Lancs region are welcomed to fix it
If you're not happy working on electronics then don't try yourself. There are a few pitfalls around about for the unwary. To do the job effectively you need a very good solder sucker and have to drill out the rivets holding the old transistors to the heatsink.
Jim
Runner, cyclist, time triallist, duathlete, Citroen AX fan and the CCC Citroenian 'From A to Z' Columnist...
Runner, cyclist, time triallist, duathlete, Citroen AX fan and the CCC Citroenian 'From A to Z' Columnist...
Re: Blower Transistors
Is it easy to take the module out as i will probably take you up on your offer.citrojim wrote:
No, but you're welcome to send me your blower module and I'll fix it for you and return it. I have a stock of spare transistors PM me if you want to take me up on this
2013 Berlingo Multispace 1.6 XTR 115bhp
2003 2:0 HDI Dispatch Van 186000 miles......gone
2000 Xantia Hdi 90bhp Forte Estate 97000 miles gone..........to heaven
New High pressure Fuel Pump and Patched ECU , Blower Module fixed by CitroJim
2003 2:0 HDI Dispatch Van 186000 miles......gone
2000 Xantia Hdi 90bhp Forte Estate 97000 miles gone..........to heaven
New High pressure Fuel Pump and Patched ECU , Blower Module fixed by CitroJim