I love Emotiva gear! We all know why: it's affordable, it sounds great, but most of all, it looks SEXY! so lets be honest about that.
Anyway, today we will be talking about a common point of failure with Emotiva Preamps and Processors- the power supply. Also, I will be focusing on the repair of a legacy UMC-1 that has the classic "Loading...." screen of death but this symptom is also found on similar Emotiva stuff.
I will describe here in plain English what is going on. If anyone would like a flow chart or pics, just PM or email me and I will try to provide them. For now, let me ramble with some groundwork:
Power Supply Specs: The Power Supply in many of the Emotiva preamps/processors have five outputs ; +15V, +12V,-12V, +10V, and +5V.
Regulators used are: 7805, 7812, 7912. I can't figure out how they are regulating the 10V which is bussed throughout the device,15V is unregulated. More on this later.
The Display logic/circuitry displays "Loading..." while waiting for the other processors to boot.
The Main processor board and I/O board each have MCUs that boot individually. They each have JTAG/Serial ports and their own RAM.
Failure Scenario #1 Very Common:
All labeled 10V test points will measure +/- 15V
7912 and 7812 will be visually blown
PCB area surrounding the main diode/bridge will look baked
PCB area surrounding the 7912 and 7812 will look baked
Z1016A1 Buck converters on Main board will be damaged, visually clear.
FB4 (SMT fuse by the Z1016A) will be open
Hope this helps. You can send me measurements and waveforms and I will try to help with your problem.
I'm looking for a spare UMC-1 power supply or for a dead UMC-1 if you have one for sale or donation.