Fried my UCD 180AD

[badman]

Dusting my preamp and something twitched... Maybe a contact wiggled in the XO, not entirely sure, but I now have a very nice producer of 13V DC on one channel.

Anyone blown (and hopefully, repaired) these before? I was under the impression that they were bulletproof having gotten half a decade of quality service from mine. I'm not terribly enthused with the prospect of having to upgrade both modules (cash is tight).

[MOER]

We have repaired several of these. If you wish us to repair yours please contact me at zedaudio@aol.com or call me at the factory at 805 526 5315

Steve

[TicksNLeeches]

Originally Posted by MOER

We have repaired several of these. If you wish us to repair yours please contact me at zedaudio@aol.com or call me at the factory at 805 526 5315

Steve

How much do you charge and can you guarantee your work? We have lots to fix

[fb]

Is there a reliability issue with these? Are the ST and HG models the same?

[TicksNLeeches]

Maybe if the OP wants to try fixing it himself he could check for expected 15 or 12 volts at the op amp supply rails, and checking for offset on either side of the coupling caps could be informative, especially if they're the stock electrolytics, which could last a lifetime but maybe they dried out and should be upgraded anyway.

Checking for proper continuity along the input path, including the connectors and cables wouldn't hurt either, the later easily done by swapping with the working channel.

You can desolder the mosfets and check them with an ohmeter for a failed output stage if worst comes to worst but check the simple things first. You stated this occured while cleaning your pre, perhaps internally, so maybe that's the source of your fault. Have you checked to see if there's any offset or short at the pre? Also easily verified by swapping with a working channel.

I'm sure MOER can walk us through the rest if there's anything more harder.

[badman]

No issues in the pre-amplifier playback chain. I'll see if I can get a gander at the offsets but I'll likely just zip it over to MOER depending on pricing.

[MOER]

We have a lot of experience with these. Due to the fact that we manufacture our own Class D amplifiers, we have access to quite a selection of low gate charge MOSFETs. Since the UCD modules were introduced there has been much advancement in MOSFET technology.

With UCD amplifiers the biggest pain is when the small epoxy coated board goes bad as one has to remove the epoxy and repair it....time consuming.

I have considered designing a drop in replacement for this board as all UCD modules use the same basic front end. I would do this if enough repairs came our way.

The dead time is adjusted on the mother board with either a trimmer or a fixed resistor.

All the parts on the mother board we keep in stock.

The over current limiters in these UCD modules are NO guarantee that they will protect into a shorted or very low Z load.


Steve Mantz
Zed Audio
805 526 5315
Zed Audio Corporation

[Jan-Peter]

Originally Posted by badman

Dusting my preamp and something twitched... Maybe a contact wiggled in the XO, not entirely sure, but I now have a very nice producer of 13V DC on one channel.

Anyone blown (and hopefully, repaired) these before? I was under the impression that they were bulletproof having gotten half a decade of quality service from mine. I'm not terribly enthused with the prospect of having to upgrade both modules (cash is tight).

For service you can always return the modules to Hypex. Please contact rma (at) hypex (dot) nl.

Repairs by third parties are not supported by Hypex.

In the case we cannot fix the older AD modules we offer you some discount if you buy a new HG modules. This is decided on a case to case basis.

Regards,

Jan-Peter

[Eva]

An improved current limiting circuit, making the modules able to work indefinitely into any load impedance, would prevent far more unpleasant things to happen than all that high-end stuff (buffers, fashion op-amps, exotic components).

I managed to add both instantaneous (no delay) current limiting (self oscillating) and long-term true-rms current limiting to my phase-shift oscillating circuit with just a LM319, a couple TL062 and another TL072 and a pair of NAND gates. TL062 used in a non-conventional way can make a poor-man four-quadrant multiplier with <10% error. These parts cost as much as an exotic op-amp, but there is substantial engineering work involved (unlike in replacing a standard part by a exotic one).

[Ianmac]

Originally Posted by Jan-Peter

For service you can always return the modules to Hypex. Please contact rma (at) hypex (dot) nl.

Repairs by third parties are not supported by Hypex.

In the case we cannot fix the older AD modules we offer you some discount if you buy a new HG modules. This is decided on a case to case basis.

Regards,

Jan-Peter

Make sure you have plenty of time on hand. I returned a brand new faulty SMPS board to hypex almost 4 weeks ago and am still waiting.
No music for 4 weeks now.
Not a happy chap.
Perhaps what is even more worrying is there a reliability issue with the Ucd modules?

Ianmac