DBX 119 schematic or pictures of the board?

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trashcanman

Well-known member
Joined
Jan 26, 2016
Messages
104
I have a DBX 117 that I've beefed up with a new power supply and op amps and now am trying to turn it into a 119 with possibly some extra mods. The 117 and 119 use the same board with slightly different components but I haven't been able to find an actual schematic for the 119, they possibly didn't even publish one.  I've managed to get about halfway from looking at photos of the 119 but it is not working properly so I must have missed something or used wrong value resistors.
Is anyone able to post a schematic or clear photos of the board so I can see if I've missed anything?
 
I have looked at the manual. The 117 and 119 share the same manual apparently as they’re virtually the same but there is no schematic for the 119. I’ve actually got it mostly working now, sounds like it is compressing/expanding and threshold control is working. The problem happens when the I have the threshold LED in circuit. I’m pretty sure everything is wired correct, could also be the op amp which I’m guessing is buffering the signal before the LED. I’ll try tracing out a new schematic.
 
So I've been trying to draw the schematic but the board layout diagram in the manual doesn't match the board so figuring out what's what is hard. What I've figured out is that when I have the additional op amp OA5 in the circuit the power rails drop out.
Below is a pic of the updated schematic which I'm pretty sure is correct and it shows that both inputs to OA5 are tied together which is as it is on the board but as far as I'm aware that shouldn't be right.
I'm certain the op amp is around the right way as I've just copied directly from photos so I don't know if there's something going on on the underside of the board.

lEuoDGF.png
 
trashcanman said:
I have looked at the manual. The 117 and 119 share the same manual apparently as they’re virtually the same but there is no schematic for the 119.

Can you work out on the 119 with the 117 schematic?
if they share the same board, the differences in circuit/schematic might be minimal
 
Whoops said:
Can you work out on the 119 with the 117 schematic?
if they share the same board, the differences in circuit/schematic might be minimal

The pic I posted above is my drawing of the 119 schematic (the part that is different to the 117 at least), most of which is  described in the manual under the modifications section apart from the threshold diode and op amp.
 
So I've been trying to draw the schematic but the board layout diagram in the manual doesn't match the board so figuring out what's what is hard. What I've figured out is that when I have the additional op amp OA5 in the circuit the power rails drop out.
Below is a pic of the updated schematic which I'm pretty sure is correct and it shows that both inputs to OA5 are tied together which is as it is on the board but as far as I'm aware that shouldn't be right.
I'm certain the op amp is around the right way as I've just copied directly from photos so I don't know if there's something going on on the underside of the board.

lEuoDGF.png
DBX-119 No Compression
Hello
1. I just bought a used DBX-119. cleaned the connectors, pots & switch and it worked perfectly with Compression set about 1.4, Mode switch set to Above Threshold & Threshold set at 100mv for 3-1/2 movies, then suddenly no sound from either channel.
2. I isolated the problem to the 119, cleaned the pots further & re-soldered several connections on the bottom of the board that appeared poor.
3. Then reinstalled it, got blasting audio at first bit of Expansion side & seemingly normal as I turned it further clockwise - BUT turning CCW in Compression resulted in weak audio (required the amp be turned up very high) from 1.0 -> 1.1 that dropped off very rapidly to no audio by 1.2 and beyond, except with very slight sound with amp turned up very high.
4. Then cleaned and lubricated the pots but same result except the audio did not blast in the first bit of Expansion - just seemed normal.
5. Using the unit for a few hours set in the first small amount of Compression resulted in occasional loud "POPs" in both channels.
6. Threshold settings from 100mv to 1 seemed to make no difference at all in the sound output.
7. I'm not a skilled technician and do not have a deep supply of parts, but I can solder and follow instructions.
Can anyone give me some guidance?
Thank you very much...Tom
 
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