Does anyone know if there is a name for this style of multi-layered printed circuit film soldered together seen in Ferrari fuseboxes? Image Unavailable, Please Login
You got it. They are common in electronics and are just called multilayer board. They aren't soldered together, they are manufactured that way, foil, substrate, foil, substrate, foil... 4 or more foil layers are not uncommon. See Multi-layer Circuit Boards. "Thru holes" are either isolated from other layers or connect to them. In your picture you can see that there are some solder connections to the bottom foil layer and some that are not. The problem with these boards in some Ferraris (the 328) is that they delaminate. I have been told this is due to heat resulting from the traces not being heavy enough for the required current. I have seen some 328 boards where the layers which were literally falling apart.
For years the Maserati Biturbo has been brutally criticized for it's piece of merde fusebox. The cause of most those electrical gremlins on that car. So I guess Ferrari's just get a pass? Does anyone re-manufacture these and improved them? There's a guy who does that for the Biturbo fuse boxes which I think comes out of some Lancia. Another Italian champion of electrical design.
That is a Double Sided PCB. It has components on top, with some traces. No components on the bottom side. If it has no traces on top, it would be called Single Sided PCB.
Johnk, Thanks for your reply. I have not deconstructed one of these MLPCB's but your descriptions jive with what it appears to me as far as construction and assembly. In the Ferrari boards not only is this not such a great design but also poorly soldered. I have once before just resoldered the exposed solder joints and it improved the fusebox. Things that did not work did work again. I was quite young and inexperienced then. I have learned to measure twice and cut once. Did I get Lucky that time? Is there a general repair methodology for this kind of board? Are there any statistics on doing a resolder and whether such a board is likely to be made better or worse?
Also fuseboxes seem to be a universal Ferrari problem. I wonder why new boxes aren't just made in the aftermarket. I thing birdman did that for 308's.
What you have is an early technology plated thru hole (PTH) board, probably using FR4 for the board material and copper foil for the traces (conductors). Your board has a component and a solder side. The bare boards are loaded with thru hole components, placed on a fixture, and then the board fixture assembly is passed over a liquid solder wave (just touching the liquid solder) where the solder bonds with exposed metal. Capillary action draws the solder into the plated thru holes for an electrical bond to the component leads. The board soldering recipe is important and includes cleanliness, board temperature before the solder bath, speed and time when in contact with the solder wave. After the soldering operation, the boards are de-fluxed and coated to protect them from corrosion and moisture. PTH boards can be repaired. Components can be unsoldered and resoldered with a soldering iron, suction, capillary action. Trace (copper) defects can be bypassed with surface wires. Solder joints suffering from low cycle fatigue (dull, crystalized, not shinny appearance) can be reflowed with a soldering iron. Minor delaminations may be repaired and stabilized. Killers of boards are heat cycles, vibration, high temperature, and moisture or other contaminants. Typical failure points on high cycle boards are individual components (temperature dependent), solder joints (heat cycle dependent), delamination (moisture, vibration, displacement dependent). Bill
In my memory, they are a 7-layered mylar construction, and extremely fragile and subject to decay for all situations and conditions outlined by 308 bob(?)
The problem with the 308 fuseboxes is that they used the crappy european Bosch (torpedo or bullet) fuses that have a poor contact area with he fuse block. Birdman fuseboxes uses the old american glass AGC style cylinder fuses with a good contact area. I'm not sure why he didn't use the more modern ATO or Mini blade types since that has become the standard in things automotive. The later F-cars have those terrible PCB boards. I'm surprised so much effort is spent on them for either repair or re-engineering. Why haven't owners just converted to a PDU like Motec or OBR. Or even this ISIS Intelligent Multiplex System - Automotive Wiring Harnesses, Car Wire Harness, Engine Wiring Harness, Auto Wiring Harness, Truck Wiring Harness, Car Wiring Kits.
The problem with the Ferrari boards I have seen is that they delaminate (the layers separate). As a result, the plating in the thru holes breaks and there is no contact to the internal layers of the board and the circuit is FUBAR, (that's beyond any repair in this case). Re-soldering, if you are lucky, might restore functionality if you are lucky. But the connections are bound to break again.
johnK.... I've also seen a lot of cracked vias. Sometimes this is a process issue where the plating is too thin. There is also a coefficient of thermal expansion CTE miss match issue, between the board material (I originally posted FR-4 but after thinking, it's more likely to be polyimide) and the plated copper vias. This mismatch is in the Z-direction (normal to the board surface) and will fatigue the barrels over time which can cause electrical intermittents and outright opens. What part of the board were the delamination's occurring? Edges, any pattern, random? How many conductive layers? Bill
About 15 years ago I had inherited some legacy equipment for a special project at work and the printed circuit board "PCB" had failed. I was really surprised how easy, and cheap, it was to use an online prototype fabricator. There are freeware programs to design the board and then it takes a little time to draw where you want the copper to go but it is very easy. You send the output to the supplier and I think it was like 20 bucks for a 2 sided prototype that took about a week to turn around. Solder on components and your all good again. Maybe a place like this could help you out. http://www.customcircuitboards.com/
I think this thread has in it an excellent rebuild section for these types of boards: http://www.ferrarichat.com/forum/mondial/209843-sticky-mondial-8-qv-3-2-t-repair-thread.html You need to scroll down a bit
The fuse box circuit boards have been an issue for the Mondial group for a long time. There were several efforts by Fchat members to deconstruct the multi-layer circuit boards and either retro-fit the boxes or come up with new ones. The last I was following this, which was a while ago, no one had come up with a reasonably priced way of producing the boards and retrofitting the fuse boxes. It would be a significant issue for the Mondial folks if someone could do it for a reasonable price.
Actually this appears to be a problem on all models because they all have these poor multilayer boards. It is especially bad in mondials for some unknown reason. I wonder if heat in the passenger footwells helps to kill these boards? I am recording huge temperature deltas in the passenger footwell of 550's by only datapoint at this time. It would be great if other owners put a thermometer back there to see what kinds of footwell heat they are seeing.
I believe that the heat is actually coming from the inadequate current carrying capability of some of the "traces" therefore acting as built in heating elements causing the self destruction. IMHO. I repair legacy audio equipment and see this all the time.
That is surely true. But the ambient internal footwell temp of a 550 driven 25 minutes on a 75*F day is 140*F! Despite the firewall insulation the heat radiates through and heat soaks the electrical components. I do not know what you know about audio equipment. Do you think this radiated heat is hurting the components? There are multiple CANBUS ECU's there in addition to the flimsy fusebox. The heat I think causes the multilayer boards to expand and contract. That can't be good for those poor connections. comments? Image Unavailable, Please Login
Yes, Dave Helms of Scuderia Rampante Innovations in Boulder, Colorado does. Per his site: "Kits now available include Mondial, Mondial T, TR and F40. Currently in development are those for the 328, 512TR, 348 and 355." see: Innovations - Solutions - Scuderia Rampante Dave recently designed, built and installed one in my '95 456GT. Highest recommendation!
I think the biggest problem is the connectors themselves heating up and transferring heat to the board. They are very poor quality and have a tiny contact area owing to the shape of the contacts. When a connector heats up this causes the connection to get even worse and then makes it hotter still.
