Studiomaster Powerhouse Vision 12, 1996

[N_Cook]

Anyone know of pics of the interior?

A previous "repairer" removed all fuses , ratings on overlay , so ok. But
did not mark the ribbons before removing all of them. Majority are mateable
without ambiguity. There are 2x 16 way ribbons with exactly the same IDC
connectors that could go to either of 2 places on the central board holding
the graphic sliders and LED bargraphs.
Completely different lengths to the ribbons , does not help to decide as the
headers are adjascent
One ribbon is from Conn1 of rear INSert sockets
The other from the CCD display board
Cannot start rectifying whatever the underlying problem was, before sorting
out this added problem

 

[JW]

Anyone know of pics of the interior?

A previous "repairer" removed all fuses , ratings on overlay , so ok. But
did not mark the ribbons before removing all of them. Majority are mateable
without ambiguity. There are 2x 16 way ribbons with exactly the same IDC
connectors that could go to either of 2 places on the central board holding
the graphic sliders and LED bargraphs.
Completely different lengths to the ribbons , does not help to decide as the
headers are adjascent
One ribbon is from Conn1 of rear INSert sockets
The other from the CCD display board
Cannot start rectifying whatever the underlying problem was, before sorting
out this added problem

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

 

[N_Cook]

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 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

 

[N_Cook]

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.

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.

 

[N_Cook]

pins 1&8 -> pins 4&8

 

[N_Cook]

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.

 

[josephkk]

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 tothe
wrong socket, unless Studiomaster were monumentally stupid at design stage!




Gareth.

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.

?-)

 

[N_Cook]

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