Studiomaster Powerhouse Vision 12, 1996

How about finding GND points on all three boards and using an ohm meter?

I have a Horizon here, which I'm pretty sure is the same layout as the Vision - I have seen lots of this series of Powered Mixer, and they are all very similar except different numbers of channels and Power amp modules.

On this one, the front panel PCB these both plug into is marked "R1A8-4". The connector closest to the back of the mixer (and thus closest to the alphanumeric display) is the one that goes to the DSP board.

This cable should be the shorter one - it thus makes logical sense that the shorter cable travels the shortest distance between the 2 different connection possibilities, the Insert cable having the longer route and the longer cable.

I seriously doubt anything will blow up if the wrong one is connected to the wrong socket, unless Studiomaster were monumentally stupid at design stage!

Gareth.

But

all

the

the

stage!

But a thoughtful designer would make one 20way with 2 redundent or blocked+cut pin identifier/inhibitor somewhere. As the ps and pa seem to be ok I don't want to compound the problem. I think a few ground tracing is the way forward, just requires removing the display board which should be easy enough

Well, maybe they'd run out of unique standard connectors, there are quite a few in this unit, and these two were designed to be interchanged without any chance of damage.

Unlike, I might add, the one in some Trace Elliots. There are two of these on one PCB, only one is actually used, and if you plug it into the wrong one it takes out part of the power supply. Now how stupid is that.

Perhaps its best to trace some grounds then .......

Gareth.

ok.

modules.

"R1A8-4".

to

easy

a

any

these

one

Unfortunately neither 16 way ribbon carries a frame ground. But that board and the other 2 boards carry plenty of BA4560 and except for a few ohms of dropper resistors, could match up +/- rail pins 1&8 unambiguously with definitive, non-matching, ribbon pinning So the long one , piggy-backed to the rear inserts board, goes to the header nearest the graphic sliders. Short one from the display board to the header nearest the display. Logical yes, but both are plenty long enough to have been inserted in either.

pins 1&8 -> pins 4&8

My logic was actually that the shortest cable joins the two connectors that are CLOSEST to each other, i.e. takes the shortest POSSIBLE route between any of the 4 possible cases. (And vice versa with the long one)

Its just the kind of thing that will now stick in my head with these mixers.

Gareth.

Applied half mains and increased to about 80 percent and some magic smoke appeared from a very lonely looking R112 ,reading a burnt 10 ohm, with a black band visible , 1/3 W on a rear board with nothing else other than 4 sockets. This connects top frame to base frame grounds, which I had not cross-connected. Will explore a bit further another day.

But

IDC

as=20

all=20

"R1A8-4".

the=20

the=20

the=20

stage!

Considering some of the monumentally stupid design gaffes i have made, i would be rather uncomfortable making such an assertion. To say nothing = of what i have seen done by others from my point of view.

?-)

Got back to this today.

70 percent mains and outputs +/-1V but go to 75 percent and outputs would swing up and down to (reduced but large ) rail voltages . Someone must have plugged something they shouldntave in the external inputs. 1x BA4560 there, except for grounded pin3 and 5, all other pins were near enough at +/-15 voltages