dbx 162 daughter card Schematic
« on: July 24, 2019, 08:56:03 PM »
Hello, I have a dbx 162 on the fritz. checked power supply voltages at opamps. voltages at the opamps are way off. I started pulling the cards to see if voltages come back to normal. lo and behold when I pulled the last card I see voltages of +15 / -15 return to the opamps. 23 +/- volts at the power supply.  Can anyone indentify the daughter card and provide a schematic? I believe I have some bad transistors. I've replaced the CA3046 IC and replaced C3 tantalium cap (broken leg) still drawing voltages.   Thanks so much.


Re: dbx 162 daughter card Schematic
« Reply #1 on: July 27, 2019, 02:29:47 PM »
I think I'm getting somewhere.  Found 2 shorted 22uf/16v tantalum caps. can these caps be relpaced with electrolytics? Anyone?

moamps

Re: dbx 162 daughter card Schematic
« Reply #2 on: July 27, 2019, 03:18:50 PM »
As I know, this is a RMS VCA module, and the schematic is almost impossible to find.  If faulty capacitors are used in power rails (+/-15V)
you can replace  them with electrolytic type.

edit: it's VCA, not RMS module , I just have this picture of it's schematic  ::)
« Last Edit: July 29, 2019, 04:03:04 PM by moamps »

Re: dbx 162 daughter card Schematic
« Reply #3 on: July 27, 2019, 05:13:53 PM »
moamps thanks you,  I replaced the 22/16v tants with 22uf/25volt electrolytics. I now have +/-15 voltages at all opamps.  can you tell me if you know? what the daughter cards are from left to right with the front of the unit facing you? thanks again.

moamps

Re: dbx 162 daughter card Schematic
« Reply #4 on: July 29, 2019, 03:58:38 PM »
It will be very helpful if you can send me high resolution pictures of both sides of all modules.
From the left to the right are output amplifier, VCA, dual RMS on front, output amplifier on back, VCA
I was most probably wrong two post up, your picture shows VCA module.

Re: dbx 162 daughter card Schematic
« Reply #5 on: August 01, 2019, 05:32:09 PM »
moamps, thanks for the VCA schematic and info on the cards. I'm making some progress. I replaced both transistors and opamps on both output cards. I'm know able to get signal thru channel one, I swaped the cards to channel 2 and all is well with both output cards and one of the VCA cards. I have one VCA card that is giving me some issues. I believe its the transistors. 

Re: dbx 162 daughter card Schematic
« Reply #6 on: August 03, 2019, 08:25:38 PM »
I'm thinking I mite need some help fixing one of the 210 VCA daughter cards. I removed all the BC263C transistors and checked HFE on all of them.  there all between 450 and 600, 2 of the higher current ones being used as the pair. I put a 14 pin socket so I could swap out the CA3046 with a known good one. checked all resistors against the good VCA board. still wont pass signal. Is there anyone out there who repairs these 210 VCA boards? Again I have one channel working fine,  both 230 output cards are working fine.     

mjrippe

Re: dbx 162 daughter card Schematic
« Reply #7 on: August 04, 2019, 10:52:18 AM »
Try David Kulka at Studio Electronics

Re: dbx 162 daughter card Schematic
« Reply #8 on: August 04, 2019, 04:17:14 PM »
Thanks mjrippe, I will send him a message. Art

 

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