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Discussion Starter #1
Anyone in the EU have a dead/damaged/non functioning SPU (service power unit / Fuse box) laying around that i can use for some destructive testing? 750, 910, 989, 1078 etc Bluetop/blacktop.

I have started a side quest into working out the functioning of the SPU with the goal of setting up a guide line for replacing it with:
A dumb micro relay set (ssVEC, Littelfuse, RTMR etc)
OR
a solid state relay set (micro relay, Motogadget mo.unit etc)
OR
Power Distribution/management Module (Ecumaster PMU, Racepak - SmartWire etc).

Having a dead unit laying around to probe with a micrometer would help.
 

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Hi Robbe!

I think I still have damaged SPU unit (blue backside) somewhere in the garage. I need to search during weekend.

It started show symptoms by flashing lights so I replaced it with a new one.
 

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FYI. From my journey with the "blue" 750s SPU, I can tell you the problem with them is HEAT
which is "fixable" to an extent with no need for any other solution.

The short of the solution is:
Dig out the polyurethane encapsulation, repair any damaged runs or pads on the board (if the unit experienced a failure), replace all four relay resistors and move them above the board, re-flow the solder on the main and power relays, then add a heat sink on the board on the opposite side of the small power relay.

The problem of the design is that the runs on the board are not large enough to dissipate the heat generated from the small power relay. This heat is compounded by the polyurethane encapsulation which leads to failing solder joint which leads to high resistance and even more heat.

1) If you have blinking head lights when the fan comes on and or continual running after removing the key or enabling the kill switch - the power really is stuck due to heat saturation. -- Remove polyurethane encapsulation and replace small power relay.

2) If you have a failed turn signal etc. a run near the power relay has failed or the solder on a related component near the relay has failed. Again remove polyurethane encapsulation and repair the damaged, run, solder, component.

910 and newer "blue" spu's do NOT use a mechanical main or power relay -- failures in those have not been explored by me.

I say give the 910 "blue" spu's a R&D...good luck! :nerd2::yo:
 

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Discussion Starter #4
Hi Robbe!

I think I still have damaged SPU unit (blue backside) somewhere in the garage. I need to search during weekend.

It started show symptoms by flashing lights so I replaced it with a new one.
I sent you a PM!
 

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Discussion Starter #5
Everybody, i am still looking for a dying, dead or damaged SPU.
 
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