McCormack DNA-0.5 Protection Circuit problem?


Hi Folks ~ My problem is regarding a McCormack Deluxe Edition Power Drive DNA-0.5 Amp. I bought this unit new in '98 and it performed flawlessly for me from that time until I moved in 2005. At that time I put it into a local storage facility - in it's original box, foam padding and plastic bag. A week ago I took it out of storage, unpacked it and left it out inside my home for a week. Yesterday for the first time since 2005 I tried hooking it up and using it. I should also say for the first time since 2005 I am also using my McCormack Micro Line Drive, in combination with the DNA-0.5 - which I think is working as it should. But, something is wrong with the amp. When I power up my cd player, dac, and Micro Line Drive, then the amp, the amp stays in protect circuit mode. The illuminated light in front stays orange/yellow (instead of turning green), and it does not "click" like it used too, after the light turned green, signaling no protection circuit problem.

I probably should not have done this, but one thing I did do while trying different options was to have a source running into the rest of the system - a disc playing in the cd player, and then turned the amp on while that was playing. When this was done, music did come out of the speakers for a split second, before shutting the sound off. I read another thread on this forum - http://forum.audiogon.com/cgi-bin/fr.pl?aamps&1332879246 where that person used a multi meter on both channel outputs with the unit powered on, but with nothing connected to either the outputs or the input. I have a digital multi meter, but I am not too familiar with how to use it - what setting it should be on. When I use the multi meter on the outputs (with nothing connected to the outputs or input and powered on) I do not get any readings. Is this the way it should be or not? I think this is correct, since I do not want to pick up a DC current. If it did pick up a DC current at the output, I think this unit is designed to shut down the amp, and shorts the input to ground.

I have not removed the top cover yet. I tried to d/l the manual/schematics from hifiengine.com, but all I got after the d/l was blank pages...I guess I do not have the latest adobe upgrade. My Firefox browser should have been adequate. This unit has never been serviced. I guess one of the rail fuses could be blown, or some of the capacitors? Any thoughts and or suggestions would be most welcome. I live in a small town, and would likely have to drive a couple hours to find a reputable service business. Also, if it may matter, my home is off-the-grid. I get 100% of my home electrical power from a PV Solar Array. I had plenty of power when I was trying to using this amp. Previously before hooking up the 0.5 and micro line drive, I was having no problem with the cd player, dac, and a NAD integrated amp, along with the same speakers.
Ag insider logo xs@2xharold_may
Hello Harold,

In all likelihood you have blown one or more of your 4 internal power supply (rail) fuses. These are 6A or 6.3A fast-blow types (5 x 20mm size) that you can hopefully find locally. Replace the blown fuses and you should be back in business.

This probably happened because the amp has not been used in a long time. Now that you are using it again it shouldn't be a problem.

Best regards,

Steve McCormack
SMc Audio
Hi Steve,

I did not expect a response from you. Thanks a lot for your reply and for telling me what to replace. And thanks for designing such nice equipment.

peace,
Harold