nvr4d
Minor Hero
Posts: 13 
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Post by nvr4d on Jul 27, 2018 14:01:16 GMT -5
No lights or anything. Fuse and power switch are fine, mains are present at PSU board. The PSU emits a barely audible clicking noise approx. each 750 ms - apparently trying to restart. Plugged a scope - looks like the +5V source repeatedly tries to start but fails.
Warranty has expired (I bought the unit in 2013), and it doesn't make much sense to ship it overseas anyway, so I would appreciate any suggestions what should I start with the PSU repair. Or C18/C19 replacement is usually enough?
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Post by Loop 7 on Jul 27, 2018 14:46:25 GMT -5
Mine was powering up but rebooting itself. I think Emotiva replaced the power supply and it's been error free. I think I had less than 30 days remaining on the warranty!
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nvr4d
Minor Hero
Posts: 13
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Post by nvr4d on Jan 3, 2019 15:38:54 GMT -5
Welp... After a while I came back to it. So I have replaced all caps with no effect. The clicking sound is still there, also there is +3.1V at +5V outputs and that's it. Looks like the clicking is caused by ICE 2A165 controller IC - it tries to start up repeatedly but ends up in the protection mode. Looks like there is short circuit somewhere down the line and I have no idea where to continue  What baffles me most is that there was no apparent reason for the PSU failure - I was travelling abroad for more than two years and UMC-200 stood in a warm and dry place, disconnected. Came back home and tada - my system is bricked. |
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nvr4d
Minor Hero
Posts: 13
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Post by nvr4d on Jan 3, 2019 18:30:40 GMT -5
Ok, going on. So far I have jump-started my UMC-200 standby mode using off-the-shelf 5V power supply. Connected it to 5V terminal on the main board, amber light came up. Now I wonder if I can just use an ATX PSU instead of that SMPS... But I guess it's not that easy.
If only someone knew what are the P-DTC, +V-STD and PWR signals are for...
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Deleted
Deleted Member
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Post by Deleted on Jan 3, 2019 20:07:27 GMT -5
Have you called Emo and got a price for a pwr sup? Anything $75 & under seems about normal
Sounds like that's it- a voltage regulator problem- bad transistor.
Wish I had a schematic to help you through it.
If I get some time over next couple days, I'll take a look at mine.
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nvr4d
Minor Hero
Posts: 13
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Post by nvr4d on Jan 4, 2019 3:57:11 GMT -5
Yes, I called them. The service representative told me that UMC-200 is no longer supported and they don't have PSUs in stock and can't repair it as well. They would trade-in my processor for a newer model, but there are no Emotiva dealerships in my country and I don't plan on visiting U.S. anytime soon, so the shipping and import duties would eat any value left in the UMC-200 Like you said, this indeed looks like a voltage regulator issue. Last night I've been probing all capacitors I replaced and found one shorted network on the low side, in +12V generator. Seems it is either ceramic SMD cap or transistor nearby who's causing it. I'll try desoldering them both and check if the short goes away. |
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Post by bolle on Jan 4, 2019 8:58:41 GMT -5
You could contact the UK company IotaAV. They sell a processor which is kind of a clone of the UMC-200. At least their power supply has the same problems which mostly can be fixed by replacing C18 / C19 - maybe they would sell you a spare PSU for a reasonable price.
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nvr4d
Minor Hero
Posts: 13
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Post by nvr4d on Jan 4, 2019 9:35:36 GMT -5
So I traced the suspicious network to diode D9 and desoldered it. It was 0 ohm both ways. Now the capacitors are not shorted anymore. Tomorrow I will get a replacement part and see if that helps. I'm amazed how the 2A165 managed to survive this and not kill the rest of the schematic. They guys who designed it know their job.
Thank you, I have sent an inquiry to them.
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nvr4d
Minor Hero
Posts: 13
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Post by nvr4d on Jan 5, 2019 11:10:33 GMT -5
After replacing the failed D9, my UMC-200 came back to life. Was a bit tough for a software guy.
So far everything seems to be in a working order, except one little old issue with left channel missing until I make a volume adjustment. It was present from the start, so I bought a reel of tantalum capacitors to replace stock decoupling caps both ways. Wonder if I should go all in and buy metal-film ones for the main stereo output.
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Post by JAJancik on Jul 7, 2019 14:33:15 GMT -5
What was the specs for that diode and is it easy to find? I am going to replace the C18 and C19, and wonder if I should knock that out while I'm am inthere.
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Post by savagecanuck on Jul 11, 2020 18:05:17 GMT -5
Hi, newbie on this forum. I picked up an UMC200 on a whim. The main switch powers on and front ring goes amber. But as soon as I press the front button it turns blue momentarily and then the safety kicks in and it shuts off.
Any advice appreciated.
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Post by 405x5 on Jul 12, 2020 13:01:44 GMT -5
There are only two things to do.
Pop the “hood” and make sure there isn’t a loose connector ribbon or otherwise in there.
If that doesn’t work, make a list of everything you need in a processor and go shopping. Anything else with that unit is now a wasted effort (sorry!)
Bill
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Post by savagecanuck on Jul 12, 2020 21:52:51 GMT -5
There are only two things to do. Pop the “hood” and make sure there isn’t a loose connector ribbon or otherwise in there. If that doesn’t work, make a list of everything you need in a processor and go shopping. Anything else with that unit is now a wasted effort (sorry!) Bill Thanks Bill. Had a feeling that's where things were headed. Guy |
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