Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) Dreaded PCB Stikes Again

The dreaded instrument panel PCB strikes again




At least I found a burnt track, so its off to my local electronics engineer tomorrow for a full board health check, a repair of the burnt track and a test of the fan switch to see if that's the reason the blower motor has gone on strike too.



I'm definitely making progress, not only have I found a clear point of failure on the board but I've also got the impossibly stiff mechanical heater control moving nice and freely for the first time in my ownership

At least it's in an identifiable place, hope you get it sorted

Sounds like you're ahead of most when this common issue strikes Dave.

Thanks for your words of encouragement chaps, but of course there's only one true expert on this one.

We're all indebted to Rog for his instrument module PCB posts

Will be interesting to see how your proper expert repairs it, I would have carefully soldered a fine insulated wire between the two exposed ends to bridge out the whole of that strip on the pcb (but I'm from Yorkshire )

I've also just found the following post that seems to point to a common link between the blower motor and these multiple PCB failures

https://www.talkmorgan.com/ubbthreads.php/topics/612561/all/pcb-fails-for-the-fourth-time

This comment has also got me thinking:


TBH rather than relying on a repair of the burnt track I really need to understand why it failed in the first place, or it'll likely just fail again

In the above post Gambalunga talks of four PCB failures on his 2012 Plus 4 before he went to an old school relay solution, Monty is a 2012 Plus 4 and my failure also arrived at the same time my blower motor went on strike, the similarities are hard to ignore.

At the time of failure I also blew the fuse for my speedo and ignition warning light, however, once the fuse was replaced the speedo and ignition warning light did return. But sadly I was now left with no illumination in the fog light and heated screen switches, although in my case the issue is just switch illumination as both the switched devices themselves remain functional.

This is what I was left with:

* No illumination of the fog light switch - Rear fog light still works
* No illumination of the heated screen switch - Heated screen may not be working?
* No indicator tell tales - Indicators still work
* No headlight tell tale - Headlights and side lights still work
* No high beam tell tale - High beam still works
* No seat belt tell tale - This light never worked in my ownership

Oddly I still have illumination in my hazard warning switch?

Like I say, I’m keen to trace the true source of the fault rather than just have my local electronics engineer repair the burnt track, could there be something in the fan relay flyback diode theory?

Yes. it’s worrying that you reported seeing sparking. I fear the track might be just a symptom and the problem is lurking elsewhere. A repair might just fail again or worse if a thicker repair wire is used.


PS - It looks like the failure might have occurred on the tracking to the heated screen relay coil.

One for the proper elec experts…. Is that a flyback diode? Could that have failed shorted?

Many thanks Rog

Actually, now that I think about it I did try the heated screen briefly this morning as it was misting up, either I didn't have it on long enough or that circuit was dead as my attempts to demist were completely ineffective

Can anyone tell me about the Morgan dealer in Italy by the name of Luigi Borghi Automobili, as I understand it he offers dash upgrades that may include a fix for the PCB problem?

I Googled the 'Luigi Borghi Automobiliand Morgan' and found this page:

http://www.morganautomobili.it/allestimenti.html

And this image on their website:



I note the above looks very much like Rog's modified dash below.



As taken from Rog's following Dash PCB-ectomy post:

https://www.talkmorgan.com/ubbthreads.php/topics/776541/1

I also read this with interest....


That last bit I've highlighted in bold sounds an awful lot like what Rog created, so I'm wondering... is there a common theme here?

I freely admit I remain quite new to Morgan ownership, I love Monty but this instrument panel PCB issue is a real concern to me as it has the potential to spoil my ownership experience, So, while I'm happy to take responsibility for my own research and have discovered much is doing just that, I'm reaching out to the collective Talk Morgan brain for any more knowledge/intelligence that may have been gathered over the years regarding this seemingly common issue?

Thanks in advance, Dave.

Modern cars including Morgan trads built 2014 on have a BCU (body control unit) to handle electronics attributable to all functions outside the basic running of the engine, timers, switch latching, logic inhibits for light operation etc. Because there is a spill over between these functions there is a CANBUS interface between ECU and BCU.

Earlier cars have variants of the awfully fragile and exposed PCB as an early form of BCU. This allows the possibility to replace with basic relay control as Rog has done, although I believe without any timers. I think I'm right in saying the logic required within the PCB to provide the momentary switch latching is lost in such case hence need to replace with simple toggle switches. Perhaps Rog could confirm but if so it appears that Borghi offers similar as his version appears to employ retro toggle switches as well.

Rog has confirmed there is a CANBUS interface from ECU via an MFU to control ignition warning light, tacho etc. on earlier models but it seems minimal compared with later cars.

Hi Dave

Borghi has now been taken over by Romeo Ferraris: https://www.romeoferraris.com/it/concessionaria/concessionaria-morgan-motors
I believe Luigi is still in the business and I don't know if he sold to, or merged with, Romeo Ferraris. In any case I imagine that he is still doing these conversions, which can be done without replacing the dash. Part of the problem was that the heater fan is actually wired in reverse to the normal logic. That is to say it is constantly powered and the control is on the earth side, unlike the rest of the system.
After several years and many thousands of kilometers I have had no further problems.
Unfortunately you would have to take a trip to Milan to get the job done. When someone else had a dash replaced he did offer a loan car for use while the job was done,
It is a good excuse for a holiday in Northern Italy (read Lake Como, good wine and food etc.)