Martin Logan Odyssey power supply board testing


I have a pair of Odysseys that I bought in 2005 and replaced a power supply in one of them about ten years ago. Here we go again.....I think. First, does the blue lighted ML badge behind the transducer panel light only if there is an audio signal applied like on some DAC's, or should It always on when plugged into house power. Second, which board is the power supply, the small one at the terminals or the large board on the woofer wall? The third question is where do I measure bias voltage to determine if it is, in fact, not producing ht voltage and, what should that voltage be.

I know that the best authority should be, and they are always very helpful, Martin Logan themselves but, in the end I would like to make this into a DIY project and try troubleshooting toward the goal of replacing an inexpensive component instead of replacing another circuit board at a cost of $380.
128x128broadstone

Showing 2 responses by broadstone

I have Odysseys that I bought in 2005. About 10 years ago I replaced the power supply in one of them and am now faced with the same problem in the other. I'm trying to avoid buying a new one again especially because I don't know for sure if the problem is, indeed, this circuit board (the new one now is about $400). I'm looking for advice on troubleshooting with issues like, what HT voltage is proper and where is it measured. Also, because I'd like to fix this as a DIY project, are there specific components on the board that are the usual culprits. Any help would be appreciated.
Even though this doesn't appear to be a popular thread, I have more info that may be helpful to the apparently few that may be dealing with this situation. I removed the board and attempted to find the culprit component(s) to the extent, at least, that this was possible with them still in the circuit.

Checking the transformer was straightforward at least and it was found to be good. 3 of the 5 or 6 stepping diodes appeared to have been overheated but sort of checked good, at least in terms of polarity. Because these diodes were the only potentially apparent problem I decided to at least give a shot at replacing them before shelling out money for a new board. It worked and the total cost at radio shack was $3.00