1989 Studio Preamp - disconnected lead from pcb

[quad48uF]

Just received my Studio Preamp from UPS. Fired it up and the signal was very weak. Opened it up to find one of the leads running from the Master pot disconnected from the pcb and I cannot tell exactly where to reattach it. The piece of tape on it is labeled MASTER. Can anyone help me with this so I don't have to pay someone to do it, please?

From other pics it looks like it came from right in front of that orange cap directly beside V2

This is from another Studio Pre from a better angle. Is that lead connecting to pcb between the blue and red resistor or to both?

 

[Acey Boy]

Can you pinpoint the problem? I have some images of mine but can’t see the problem in your picture.

 

[quad48uF]

In the first picture I am holding up the wire with my black plastic tool. If you are looking at the Preamp from the front, it is the grey wire attached to the LEFT lug on the 2nd pot in.
The second picture is just another Studio Pre I found online that has clearer shot of where that wire might go, but I just want to make sure.

 

[Jay Omega]

Do you have a meter with a continuity checker? Not the easiest to read, but the highlighted node is where the wire should connect. Maybe look at the V2B area (side of V2 closer to the input jack), find the 3.3M(?) that ties to pin 7, and solder it to a pad on the opposite side of the resistor than the pin 7 side. If it's not 3.3M, looks like there are three resistors that connect to pin 7, a 150k, a 274k, and another one (the one that looks like it has a value of 3.3M). Happy hunting!

 

[Acey Boy]

In the first picture I am holding up the wire with my black plastic tool. If you are looking at the Preamp from the front, it is the grey wire attached to the LEFT lug on the 2nd pot in.
The second picture is just another Studio Pre I found online that has clearer shot of where that wire might go, but I just want to make sure.

Ok check out these pics…the one shows your culprit cable with both ends marked with red highlighter. The other is the best closeup I have of the landing point.

 

[Acey Boy]

Here’s a wider shot of the landing point angle.

 

[Jay Omega]

Do you have a meter with a continuity checker? Not the easiest to read, but the highlighted node is where the wire should connect. Maybe look at the V2B area (side of V2 closer to the input jack), find the 3.3M(?) that ties to pin 7, and solder it to a pad on the opposite side of the resistor than the pin 7 side. If it's not 3.3M, looks like there are three resistors that connect to pin 7, a 150k, a 274k, and another one (the one that looks like it has a value of 3.3M). Happy hunting!


View attachment 862

After a closer look, I gave you some bad info! The wire goes to the node of top lug of the master pot in the schematic rather than the wiper. You should be looking for the node that connects to the 22.1k / R212(?) junction downstream of the 100n off the V2A plate. I’m unsure of the designator or the value of the other resistor connected to that node

 

[Rbh]

I just replaced a half dozen Orange caps on my Studio pre about 2 weeks ago. Doing anything under the board is a bit difficult. I would recommend that you do solder from the back side to make sure you get a good solder joint if possible. You may be able to solder from the top side if you have a direct component lead to attach to. If you can be assured you locate a correct component lead to solder to. Do it, because accessing the bottom side is a pain.
What I ended up doing was to basically remove all of the back panel jacks, lightly squeeze the push in plastic board capture pins and allow the board to lift up off the pins. You need to do it starting on one side of the board and work towards the opposite side and just lift the board section adjacent to the pins enough to release the squeeze clip. I also had to release the reverb from it's springs and the reverb driver transformer screws. You can then carefully pull the board a little bit towards back until the leds slide out of their holes - then slowly stand the board up right enough to locate the intended through hole for the wire. Plan to remove the broken wire. The circuit board copper is not very thick, so be precise. It's a bit of a challenge - but do-able. It would be great if we all could come up with a clean schematic for this thing.