Halcro DM10 repair


Does anyone knows how to repair the Halcro DM10 preamp in U.S.? My Halcro DM10 recently has no sound coming out of left channel when in the middle of listening session to the phono (it is not tuntable since I swapped the interconnect cable), line section appears to have no issue. The only way to solve this issue is to power cycle the unit, then it sounds just fine for another couple hours before left channel stops working again. Since there is no degradation in the sound quality and power cycle can solve this issue. This tells me that the audio circuitry in the analog section appears to be fine. The problem appears to be in the microprocessor control section, possibly the relay. I am trying to open it up but I do not know how to open it since it has no visible screws. I am wondering does anyone have the experience to open the Halcro preamp/amp? or does anyone knows how to get the schematic? I heard Halcro is out of business and I also do not wish to sent it to Australia if it is a simple fix.
yuchuinlu

No, I am running it as line stage, do you have the same issue on the left channel?

Thanks for the update. I will try to investigate further after I get the second pre-amp. Right now, I am using it as line stage....
Exactly the same. Replacing phono relays did not help. Investigating further with Lance...
No, I have not had any chance since I am using separate phone stage. Do you have the same issue in the left channel as well?
@yuchuinlu@mbachemist
Did you have any success witb the repair of your phono stage? What did help?
Thanks!
No, I have no time to pursue it further. Currently, I use it as line stage only since I acquired Audio Research REF 2SE as my phono. Do you have the same problem in left channel as well?
I have a DM10 and have experienced the same set of issues with the phono section. Did you have any success with the repair of your phono section?
thanks for any updates. 
Thanks a lot for the info. I will try to see if I can open it up first.Right now, it is still working, but I am afraid the left channel will eventually stop working all together.
Not much good news for you unless you live in Australia.....
Halcro did go out of business and despite at least two attempts (to my knowledge) to re-establish themselves....are still defunct.
You can open both the DM10 and DM58-68 amps by way of allen key screws accessed through the slots between the vertical aluminium heatsinks on the side of the amps.
But this is what you will find inside
http://i.imgur.com/aViBjTL.jpg
PCBs covered with resin to protect the proprietary circuit design that Halcro owns. And despite the fact they are defunct...they will not release the designs to enable others to work on these circuits.

Here are the contact details of the original circuit design engineer in Adelaide who still services the Halcro gear:-
Lance Hewitt

Independent Technical Consultant

dmrepair@adam.com.au

+618 8388 2045

+618 405 16 39 39

Good luck.


They still support and do repairs last time my mates DM70’s went down, about a year ago.

Pick your country. http://halcro.com/dealers


Cheers George