Page 1 of 1

MCI JH 618, Rise from the dead!

PostPosted: Thu Sep 07, 2017 3:00 pm
by Ryebot
Hello Everyone!

I recently acquired MCI JH 618 SN 0308 built May 1981. It has been dead for a while, and I'm really hoping to resurrect it. The Audio Power Supply is fried, but the peripheral supply works! (The lights are on, but nobody's home...)

I have a quote from GRS in Hemet, CA for a brand new 18V (and phantom) supply. However, the main and most confusing item is that the -18V audio power rail is shorted to ground and +18V rail all over. I cannot find out where this is happening. It certainly won't help to have 8-16 Amps of fresh clean power running through that!

So before I get a new PSU, all of the channel modules have been pulled, and the Master section motherboard has been disconnected and removed from the rest of console (all power, ground and jumper connections de-soldered.) Before I pull the entire harness out from channels 1-18, and beyond... does anyone have an idea where I could check that I might be missing? I am an amateur tech at best, I know enough to be dangerous, and stupid... But I'm very willing to learn, and certainly get a lot of enjoyment out of it.
The previous owner(s) did quite a hack job all over... If anyone is interested I have many hilarious pictures to share.

It's not all bad, however.

SUPPOSEDLY, all of the channel modules are in working order. HA!

Other highlights include 2 dbx goldcans in the master section, one John Hardy preamp, and 2 Vari-Q channels. There is also a mystery non-factory group return(?) module fashioned for the lower right of the board, under the patchbay.

No automation and VU meters make this console a bit easier to deal with, but still a much bigger project than I've ever attempted! Hopefully some of you out there know the right questions to ask, and can guide me... I'm grateful for your wisdom! I'm a long time lurker, first time poster.

Many Thanks in advance!



Re: MCI JH 618, Rise from the dead!

PostPosted: Thu Sep 07, 2017 4:21 pm
by Ryebot
Some pics of the Mystery Module...

Mystery Module.jpg