Right, I need some advice:
Problem: Heater control box works fine EXCEPT the air flow control motor.
I have shoved 12v across the motor and it worked - so logicon is the prime suspect.
So I resoldered EVERY joint on the locicon pcbs (3 boards) with no joy.
Now I have read that the motor drive transistors can fail due to mazda using the wrong lube in the motor unit which causes abnormal load in very low temperatures thereby burning out the motor drive transistors , fine
lets have a go at them then - BUT which are the transistors on the board I need to replace ??? :3Confused also are there any suspect diodes or resitiors that I need to change in the process - agagin - which ones !
Anyone been here and done that ?
If so please let me know - or of there is a circuit diagram of the logicon anywhere
Thanks
2connect
hiya matey - i have a spare on , only prob is - i have packed it away for a house move - if you can wait a few weeks - i can send it over to you
no idea if it works or not - and no use in my car as it doesnt have the AC switch on it
cheers
stu
failing that i have a AC one you can buy or even try to see if it works if you want.
I think the transistor that fails is stuck on the outside of the Air pump motor - it\'s a power transistor. Don\'t know any details beyond that.
Grinder: thanks a million , i have emailed you about your generous offer, brilliant , thanks.
pdtaylor18: thanks for the offer, if grinders goes astray in his house move i\'ll get back in touch, what kinda £\'s would you want for it. Thanks.
prof: you have me confused now, I have stripped the motor that is the problem which is the air flow control motor, there is no transistor in there, should i be looking at the actual air pump motor now? I cant see how or why a control transistor would live in there for the air flow motor?? can anyone claify this?
thansk for the offers and posts
2connect
oops - my mistake - I thought you meant the air blower motor - that has the power tranny on it.
Can\'t remember too much what the Logicon looked like inside, but I don\'t think it had discrete transistors - more likely uses one of those darlington driver arrays - ULN2003 etc.
If anyone has a pic of the inside of one - I could probably identify the chips
MAZDA RX7 HEATER CONTROL UNIT ( LOGICON ) REPAIR OF THE DARLINGTON TRANSISTOR ARRAY - INFORMATION FOR OWNERS
Problem: No feed to air direction motor (screen â€" feet â€" face vents) rest of the unit is working;
I have already read the there is a documented error where the grease in the motor is unsuitable for low temperatures therefore causing seizure / overload â€" inspecting the circuit there are NO SAFETY electronics for a safe cut out in an overload situation SO either the main fuse will blow (unlikely as it will be 5 or 10 amp probably) so the transistor(s)are gonna blow.
INTENDED SOLUTION
1) Dry joint the unit s 3 pcb boards (re solder all connections adding new flux) (about a 50% chance of a fix)
2) Replace the transistors and any blown diodes (should have fixed any remaining unit)
My plan was to replace the 8 main (transistors 4 sets of 2 pairs) and check all the diodes on the board with a multi meter .
The transistors are 2 types, marked as follows:
1) B764 E-6K
2) D863 E-6k
***note there are some other transistors on the board also â€" test and replace any blown ones ***
It was my intention to document the rebuild and put it out there for the benefit of other owners
BUT....
I have spent about 4 days trawling the internet for the model numbers and electronic specs of these transistors WITHOUT ANY JOY WHATSOEVER â€" also i was hoping to get some circuit diagrams that might tell me BUT NO JOY ... so this is the current situation
I cannot rebuild the unit because I cannot identify the equivalent replacement transitions
Or identify their spec â€" I need to know
Category ? (well that looks like a darlington transistor)
Description ? (probably driver)
Info ? (Bipolar NPN I have no idea)
Spec ? (manufacturer data sheet spec data??? Usually obtainable when you can trace the bloody original transistor code)
VOLTAGE ???
CURRENT ???
TYPE ???
CASE STYLE ???
Sanyo made a part called a 2SD863 â€" no luck on the other code â€" no idea if its the same part.
*** Note I also read warnings about oddball darlington transistors that have diodes and resistors built in... so I don’t know if this is the case here but it would just make the task even more impossible*** (maybe that’s why the second part of the code looks like a resistance value)***
So basically do not bother wasting your time trying to rebuild on of these logicons as it is a bloody nightmare
The reason i am documenting this is that i could not find any info about rebuilding the unit although I bet I’m not the first to try â€" the reason for documenting this now is to sav3e other people wasting their time
CONCLUSION
DONT BOTHER â€" SOURCE A NEW UNIT IF DRY JOINTING FAILS
FINALLY
I might have another crack IF anyone can giver any futher information or web links to the following:
1) Logicon & Logicon amp (the piggy backed black box) Circuit diagrams
2) Replacement transistors codes â€" suppliers
3) People who refurbed or remanufactured these boxes
I AM NOW DESPERATE FOR A LOGICON (PREF NON AC â€" BUT AN AC WILL DO NICELEY)
MY BEUTIFUL ROCKET IS IN BITS :Hammer AND SO AM I! SO IF YOU CAN HELP OUT THEN GIVE ME A SHOUT. MANY THANKS
2CONNECT
If the transistors are only acting as switches - turning motors on and off, then just selecting the correct type NPN or PNP or possibly MOSFET (unlikely) with adequate voltage / current and power ratings should suffice. You could use components rated at higher power and current so that they are less likely to blow in the event of an overload.
From the wiring diagram they look like they are in pairs of NPN/PNP - they have protection diodes across them in the circuit, so these probably don\'t have anything built in. My guess is they are just used as high gain switching transistors - and the frequency requirement won\'t be high - so some medium power switching transistors would proably work - get a matched pair. Most transistors will have adequate voltage ratings - the circuit is only working at 12v. The current rating may need to be 1 or 2A, so the range for smaller package transistors is more limited.
Could try ZTX653 (NPN) and ZTX753 (PNP) - these are rated 2A, 100V and 1 Watt, and have a gain of 100 these are in the very small e-Line package:
http://uk.farnell.com/jsp/Semiconductors/Transistors/ZETEX/ZTX653/displayProduct.jsp?sku=9525580 (http://uk.farnell.com/jsp/Semiconductors/Transistors/ZETEX/ZTX653/displayProduct.jsp?sku=9525580)
or go for TIPP111/TIPP117 - Darlington\'s NPN/PNP in TO92 case style - these are also 2A, 0.8W with gain of 1000:
http://uk.farnell.com/jsp/Semiconductors/Transistors/BOURNS/TIPP111./displayProduct.jsp?sku=426945 (http://uk.farnell.com/jsp/Semiconductors/Transistors/BOURNS/TIPP111./displayProduct.jsp?sku=426945)
If all else fails I have a spare one in my pile of bits from an 89 Egi - and I\'m in the midlands (Wolves) quite often so if you need it yell. :)
This is my plan now,
1) Use a new unit to get the rocket back on the launch pad, hopefully from glen quite soon (thanks glen:Thumbsup! )
2) have a go at rebuilding the old unit (thanks for the info prof) if successful then I will do a “HOW TO” on fixing the darlington transistor array – including the new part replacement transistor codes (thinking of going for the higher amperage ones prof)
3) Drive the rocket around again ASAP with a big smile on my face whilst pressing the air divert buttons just for fun. – having the rocket in bits is starting to make me glum now especially as I know I’m missing out on these rare mild & sunny winter days. :eek
Sincere Thanks to all you guys
Hi Prof,
Im having a small amount of bother sorting out me B E C legs on the old transistors for the purpose of meter testing.
Basically I know im looking to effectiveley measure 2 diode readings in one direction only from the Base, now im assuming the middle leg is the Base on PNP (is that right?) and if this is the case which leg is the base on NPN - the right or left leg? how can I be sure ?? as I need to identify for sure which type is which.
Also do you have a circuit diagram? if so can you email it to me at
2connect@btconnect.com
Now all I need to know is how to measure a zenner diode with a digi meter - right off to the t\'internet to find out
Thanks again
OK - I take it your checking the current tranny\'s out - not sure what package they are, but probably they are either eLine - very thin abotu 1mm thick package - or they are a TO 92 package - the more common style. There are lots of variants of this package :(
Probably the best way to identify the transistors base lead is to see which leads connect to the motor - for both NPN and PNP transistors these would be the collector leads. The Emitter lead is connected to the power line - 12v for the PNP transistor and ground for the NPN transistor - that leaves the remaining lead as the base.
I\'ll forward you the circuit diagram tonight - as I can cut and paste the pdf. I\'ll stick some info about common transistor pin outs as well.
Your zenner diode is just like an ordinary diode in one direction - so on the diode test on the meter it should give 0.6v or there abouts, in the other direction it will be open circuit until the zenner voltage is reached - then it\'s like a resistor. It\'s not so easy to test on a meter. If the circuit is powered, the zenner will usually have the voltage on it that it\'s rated for. The cathode (stripe or mark on case) is always wired to the more positive side.
ok, here is some more bumf.
Transistor pinouts - like I said there are some variations on the TO92 case - but the common one is straigt TO92 - which is BCE from the top when viewed from underneath with the flat side on your left ;) hope that wasn\'t confusing :3Confused
Here are some pinout (http://www.technifest.com/transpins.htm) diagrams.
You can get a link to the wiring diagrams on Gary\'s Rotaryart site:
http://www.rotaryart.uk.com/acatalog...iterature.html (http://www.rotaryart.uk.com/acatalog...iterature.html)
the one you want is
http://www.rotaryart.uk.com/acatalog/19912ndGenS5wiringLHD.pdf#page=66 (http://www.rotaryart.uk.com/acatalog/19912ndGenS5wiringLHD.pdf#page=66)
I\'ve attached a simple diagram to this - it shows how the driver transistors are arranged - it\'s not so easy to see on the circuit as they are so small.
If you need anything else - let us know - I\'ll see if I can help.
this is a heavy thread to read !! :D
also part of my logicon plan is this ...
if i get a logicon donated to me , if i get my original logicon working i will return this donation back to the donor at their request or if they preffer I will donate it on to somone in need, thanks guys
what can i say prof ?
thanks for all the help info links and advice ...
BRILLIANT!
No worries - glad to be of service - we will all no doubt have to start fixing more and more bits of our electronics on these cars - for those that find the issues first and the solutions - it means the rest of us can benefit.
I had to resolder all my connections in the logicon to get the led\'s working, but the rest of mine seemed ok. I shall watch the motor stall issue though - good heads up. :cheers
Apoligies if people are finding this a bit heavy going to read - the intention will be to produce a simple step by step document for logicon owners that says something like:
Air vent direction dont work? then replace: x y x comonents with a b c equivelent components, available from XYZ Shop: You will find em marked T1 D2 ZD3 on the board - (make sure you get em the right way round)
It will leave out all the technical gubbins that the average owner just wont want to know, they just wanna know which new bits to soldler in and where. .... in fact thats actually what I want now really , but as its not out there and its a common problem then somdodys gotta do it aint they?
So the end result should be an easy to follow "how to fix document" that goes to the next step beyond just resoldering the dry joints as this wont work for everyone, so basically I\'m with the prof of this one as there are only going to be a limited number of logicons before the ONLY option is to trace & rebuild these circuit faults.
I\'m no expert but i know enough of the basics to "have a go" - I might end up with a smoldering pile of duff electronics amd a nervous breakdown - but hey at least i had a go, and if I can nail the bugger then others are sure to benefit, the electronics should cost under a tenner and it should take me no more than a few hours to try once I have the bits - so wish me luck as i wave me tenner goodbye - ha ha :Laugh
Right I just need a four hour slot do have a bash now ... :eek:
2connect
Really a BIG stuggle this problem - anyway landed a new logicon for £25 and now works perfect.
Also found the ROOT cause of the problem ... somebody had tinkerered with the linkage - it wasnt set up right therefore on sertain settings the motor was being held under load > therefore burning out the transistors and or diodes on the pcb... traced the stage (thanks for all the help and info prof) only to find MORE componenets with non transfereable values (NIGHTMARE) anyway in the process gathered some uselfull information for other owners so I will (when i get a chance) type up everything and post it with a view that somebody else may be able to fill in the gaps and finish a "how to fix your logicon" document ... im doing this because it would be nice to think I dint waste 5 days of my life (and othet peoples time) rfor nothing!!!
2connect :cool