DBX 900 Mods

[Link555]

This 900a Series is in to get TRS jacks in to replace the terminal connectors. I made a Custom PCB to replace the board mount terminal connector and reuse the original metal work with a 3D printed mounting plate.

 

[Link555]

Circuit boards came today... a couple stand offs and 3D printed insert and this will work!

 

[Link555]

Desoldering was a lot of work.....but it's finally done..

 

[Boswell]

Nice work!

 

[Link555]

Now onto the Power supply. Just doing some recapping. Interesting design the Power transistors are connector mounted...

 

[Link555]

One more of the PCBA

 

[Boswell]

Ah-ha, the old TO-127 package! It looks like the middle 4 Darlington transistors are in this package mating with the 0.156" connectors. The outer two regulators are conventional TO-220, going directly into 0.1" sockets.

Easy to take apart, but it's a very unreliable way of connecting to power device leads. Any increase in contact resistance through ageing can quickly build into a run-away failure.

 

[Link555]

Exactly what I was thinking, I might be taking that connector off and soldering straight to the pcb

 

[Link555]

Well the plate is done.... 38 holes and two squares later... not bad for a sparky..

 

[Boswell]

Pretty impressive! Is the rear panel in the same position as it was originally, or did you have to move it back a bit to cater for the length of the TRS sockets?

 

[Link555]

Actually I brought the back out further, the racks has wings the project backwards ...so it works

 

[Link555]

Power Supply Recapped and Transistors and IC soldered directly to the PCB. I removed the connector to hopefully increase the future reliability...

 

[Link555]

With a little fiddling I got the DBX 900 chassis back together and working.... Now onto the card repairs...

 

[Link555]

And now repairing 8 dbx 900 series cards... 6 904 noise gates and 2 903 compressors.

One compressor was the worst off three funky opamps and one internally disconnected 20k threshold pot.

 

[Link555]

Repairs done cards inserted and blank off panel made...tested and ready for pick up...

 

[Boswell]

Looks like.a job well done!