Working on fix ECUs... AND FIXING WITH SUCCESS!!!

[Nacho-RT74]

what you read... I will show you pics later but everything points out on THIS being the guilty on the MP chromed units:



with just one difference... NO MOTOROLA EMBLEM ON IT... just the ON letters... a copy of originals? dunno.. if it is, maybe that confirm the use of bad quality components ?

By the moments only was able to find the MJ10005 replacement. Is the closer I could find to the original specs but will work to discard the fail and making it work

IF IS THIS THE PROBLEM is an easy serviceable piece to replace AND CHEAP. Just need to cut the epoxy area on that location, replace and refill with any regular black silicone.

the bad is: FBO box got erased the numbers on transistors and I don't think he will be agreed on tell me that number

[Nacho-RT74]

SUCCESS!!!SUCCESS!!!SUCCESS!!!SUCCESS!!!SUCCESS!!!SUCCESS!!!SUCCESS!!!SUCCESS!!!SUCCESS!!!SUCCESS!!!SUCCESS!!!SUCCESS!!!SUCCESS!!!SUCCESS!!!SUCCESS!!!SUCCESS!!!SUCCESS!!!SUCCESS!!!

fixed the first one... pics soon!

[Nacho-RT74]

SUCCESS!!!SUCCESS!!!SUCCESS!!!SUCCESS!!!SUCCESS!!!SUCCESS!!!SUCCESS!!!SUCCESS!!!SUCCESS!!!SUCCESS!!!SUCCESS!!!SUCCESS!!!SUCCESS!!!SUCCESS!!!SUCCESS!!!SUCCESS!!!SUCCESS!!!SUCCESS!!!


fixed the SECOND ONE!!!...
what I need now ? the right Transistor to get same specs from Module.

Shame FBO transistor got erased the numbers from manufacturer

[Musicman]

Nacho

I have an FBO A688 back at the house... I'll look at it tomorrow and see if I can find anything.

Mike

[Ghoste]

Good work Nacho! 

[Nacho-RT74]

Nacho

I have an FBO A688 back at the house... I'll look at it tomorrow and see if I can find anything.

Mike

Don uses sandpaper to remove numbers from Transistor to keep the secret. I don't think you'll find any number on it

[Nacho-RT74]

promised pics. Need to note these pics were taken AFTER the process of dissasembling and in fact after the first module test when the new transistor was solded and mounted on car, not allong the process, but you'll get the idea

first the steps dissasembling everything. Removing the black stuff:



how it basically looks after that:


This is the pins area... These pins are full of tin and after remove that we found they are riveted, so we had to use a Dremmel to loose them. For the test they were placed back, and full filled with tin and solded back to the printed circuit board, but to placed back stronger, is better try to drill a small hole and use a small screw to attaching THEM back, then solder back on to the printed circuit board.


these are the transistor solding points and screws... the remove process is basically just remove the tin and screw them out... fairlly easy and THE MAIN GOAL ON THIS like you will see later.


how it looks the transistor and disipator plate out of the case... fairlly easy to remove, simply pulling it out:

Need to note TEH TRANSISTOR TESTED DAMAGED once removed. But, if the transistor tested bad why we didn't stop to dissasemble and simply replaced it ? because we tried to find an internal reason for the failure.

THE GROUND POINT between case and circuit board... is basically a pin bent over the circuit board, like a nail and solded. Remove the tin and straightened up the pin


THE CIRCUIT BOARD!!!, of course when pulled out it was full sticky of the silicone, epoxy or whatever is full filled. This is already clean. Not hard to do


we checked all diodes and transistors on board, they simply gave us PERFECT measurements. Same with resistors, although for a better test they were removed at one ledge from board to don't read the ohms of the circuit, and just the resistor. ONCE AGAIN EVERYTHING WAS PERFECT.

The conclusion... Transistor simply got a premature fail by itself... maybe bad component quality ? NOW WE HAVE THE DOUBTS... which one is original and which not ? My friend told me that latelly Motorola is not using anymore the M emblem on them and now they are using the ON letters. beside this, you can note the Pn printing quality. If you search on the ebay, is funny to see all transistor stating MEXICO but... sent from China/HK ? LOL...

This is the full pieces set. You'll notice the cork. Is not more than a gasket beween circuit board and ECU plug location on Case. Of course it was glued to the silicone all the outer edge around, not the faces... this is a clean view.


You can see there the white stuff looks to be an spacer and gasket for the transistor ledges. Also the ground case location.


WE ASSEMBLIED BACK and used the closer to original specs Transistor available locally, The MJ10005. my friend who is really a tech told me the one I got is a Chinesse unit with the motorola emblem on it, not original either. But since this was a basic test, not the definitive refurbished job it was to work... LIKE IT DID!!!

[Nacho-RT74]

If you care about transistor specs, here is the original one

http://www.datasheetcatalog.org/datasheet/motorola/MJ10012.pdf

and here is the one we are using ( well maybe not an original, but should be close at least )

http://www.datasheetcatalog.org/datasheet/motorola/MJ10005.pdf

Dunno if the small diffs on specs really will affect on performance. My friend told me that even could work better, but he is not so expert to predict it. The original one is specifically made for ignition stuff as the datasheet says

[Nacho-RT74]

Now, that was the first job. Known the only component reading wrong was the transistor, we tried going straight up to that on the second box:

JUST CUTTING OUT the silicone on transistor area:


Removing screws and tin, voila, transistor out:


front face with transistor out and heat plate disipator ( or part of it )


welding back the replacement unit:


finished job on back:


( need to note will refill with black silicone but not now, will test it better on streets, after that maybe will aply a light layer of vaseline and then the black silicone to get it easy for a new service just in case, or when I get the correct transistor, Original Motorola  )

and now... THE FRONT FACE FIXED:



needles to say, that as I told you previouslly THIS UNIT WAS MOUNTED ON CAR AND ENGINE STARTED UP PERFECT ( this was the unit which died after 24 hours! )... just like the first one we reassemblied back... need to test it on streets yet

[willard]

Congrats! Finally someone pinpointed the problem and found a solution! Great news for the mopar family.

[Nacho-RT74]

specially cheap... less than $3 each, and able to do it at home if you have the skills.

so, no more $70 to spend on Chromed, or maybe $50 on Oranges. AS FAR the fail is the same, what it looks it allways be ( by now 2 of 2 )

rest to check if failure is the same on another chromed box I have around but OLD ones ( with the odd printed PN ) what printed circuit board is diff although components looks to be the same. Will replace the FBO one too, although I don't think will find the correct transistor substitute... a friend of mine have around 3 Orange ones ( one from the old days, rest newer ) and will proceed with the same.

[Ghoste]

Knowing very little about electronics, what would be the reason for Don keeping his transistor number a secret?  What aspects of the operation of the ecu would it change?

[Chryco Psycho]

What Don told me was that his transistor switches faster which in theory is what causes the timing light to wander by 2-3 degrees by switching too slow ... if you can believe what Don tells you ?

[Nacho-RT74]

If that's true THERE IS A GOOD CHANCE, the MJ1005 ( the unit I used ), could be closer to FBO specs... if you read the MJ1005 datasheet specs.

For those who still don't know, the reason why the A688 FBO unit is gone is because Standard who was the Modules manufacturer to DON, said BYE BYE to USA lands and they are building their stuff outside USA... so they weren't able to buy for him his units anymore. That's at least what he told me

[Nacho-RT74]

Being more specific on reference what you said:

What Don told me was that his trasistor switches faster which in theory is what causes the timing light to wander by 2-3 degrees by switching too slow ... if you can believe what Don tells you ?

what MJ10005 datasheet says about:

The MJ10005 Darlington transistor is designed for high–voltage, high–speed,
power switching in inductive circuits where fall time is critical.

[Musicman]

Nacho

I pulled the FBO unit apart... it's a lot different than the MP box in many ways, and not just the components. It's a little more difficult to replace parts on these units since the entire board is set in a bed of black silicon rubber. The power transistor would be easy enough, but the rest of the components would require that the board be removed, and this would be a little more time consuming... easily done, but time consuming. They're actually quite nicely made... I was actually impressed, not what I expected to find at all. I pulled the power transistor hoping there may be some info on the reverse, but no luck of course. As you said, someone purposely had the markings removed during assembly. I sincerely doubt that Don is responcible for this however, more likely it was the manufacturer.

Here's a shot of the board...



... and the power transitor with no markings of course...

[Nacho-RT74]

the circuit board needs to be removed on all the units anyway to replace any component but the amplifier

That one looks really pretty much similar to the OLD MP chromed unit I have laying around... with resistor ballast and all. AND EVEN THE COMPONENTS FACING UP. Will need to be further checked but looks to be pretty much similar, not the same but similar. Diff disposition by sure. The newer MP unit circuit board faces down the components and makes mandatory to remove for just testing.

on the printed circuit board facing up, you still can test dieletrical components ( transistors and diodes ) since their test is not affected by the circuit... not like resistors.

anyway, a blown resistor is VISIBLE. Is hard to get damaged a resistor being not the fail visible.

Just by a guess, replace the transistor with the one I used and just test it for working order, not performance... If works, then we got the failure, just need to find out the right component, which, obviouslly and logically I don't think will be informed by Don

[Musicman]

That's not a blown resistor Nacho, it just looks that way in the picture... it's just some of the old rubber. I didn't clean the board, I just took a picture of it as is. 

Looking at your pic's of the MP board and mine from the FBO unit... there are a number of differences, but I'm still betting that the MJ10005 would work in this circuit.

[Nacho-RT74]

here is the view of the Older MP Chromed box unit... note the similarities with FBO and the distance from the newer MP unit

This is with the replacement component already solded, ready to be tested.





The original unit have some numbers erased and the brand looks to be BRITAIN

it reads

87 ( something here what dunno if is some emblem or numbers ) 49
3597525
BRITAIN

[Nacho-RT74]

That's not a blown resistor Nacho, it just looks that way in the picture... it's just some of the old rubber. I didn't clean the board, I just took a picture of it as is. 

no, sorry, I'm saying a blown resistor WILL BE NOTICEABLE, just dieletric components can get failed and still looking good outside ( ex, the amplifier transistor )

so I think testing the transistors and diodes on the way is visible on box, will tell you for a good or bad component. And resistor just looking at them. That makes no need for remove the board from case and work on it like it is... diff than the newer MP units where remove the board makes mandatory for components testing.

[Musicman]

OK... that new pic makes better sence of what you were saying earlier. The old Chrome box design is "very similar" to the FBO unit.  Or more accurately stated, the FBO circuit is very similar to the old Chrome box circuit.

That said... the MJ10005 should do just fine.

[Nacho-RT74]

yes sorry, an image worths million of words

I still have not tested the Old MP box withe newer transistor...will do sometime in the afternoon

[Nacho-RT74]

New update about the older Chromed box. Didn't work quite as good. Started up fine BUT misssing some beats. Will check further on this later

Officially begining the street test time for the newer Chromed box with the replaced transistor.

[ChargerST]

Could you make a drawing of the circuit board and the components? My dad is a retired electronics teacher and he has got a cicuit board printer - need to give him something to keep him occupied  

Great work btw! 

[tan top]

awesome work Nacho    clever stuff