BSS DPR-402 repair and IC identification

[phantombox]

Hello guys.
Another friend gave me a BSS DPR-402 compressor, again to see if I could put it back in business. After connecting the BSS to a console (DI-box with a cable and my finger on the compressors input), I could hear a whistling-ish sound on one channel and nothing on the other side. No reaction whatsoever to any messing around with the controls.
I do have a schematic but it is a scanned document in low resolution so you really cannot read the detailed writing. Also, op-amps and other ICs are unspecified in this document, I guess it is the same that's available on this forum.
On the real circuit board are a few ICs that are made unrecognizable (covered with paint, on purpose!). These are IC5 (DIP16) on the upper board and IC9 and 24 (both DIP14) on the lower board. All other of the DIP14 ICs (also painted over) appear to be MC14066B, and there are 2 ICs LM3915N (clearly visible) on the upper board. All op-amps are LF353N.
There is a DIP8 socket on each channel with no IC in it (and no ID anywhere next to it), the strange thing is that V+ and V- on these sockets is pins 3 and 7 and pins 4 and 5 respectively, I never came across this configuration before. Maybe that's the reason for being empty sockets...
If anyone could identify the painted ICs, and confirm that MC1406B is the correct number, that would be great.
Also, any hint as what to look for.
Thanks a lot in advance.
I still have quite some testing to do on this gear.

 

[Khron]

There is a DIP8 socket on each channel with no IC in it (and no ID anywhere next to it), the strange thing is that V+ and V- on these sockets is pins 3 and 7 and pins 4 and 5 respectively, I never came across this configuration before. Maybe that's the reason for being empty sockets...

Power on pins 7 and 4 is standard for single opamps in DIP8 packages.

https://www.soundtronics.co.uk/images/detailed/23/Ext-2240-081.jpg
That being said, there seemed to be some knowledgeable members posting in this thread not long ago:

https://groupdiy.com/threads/bss-dpr-402-service-manual-request.79546/unread

 

[pucho812]

the dip 8 sockets without ic's is normal there should be one per channel. I have 3 units that I have been working on. I have them in various states of finished.
2 out of 3 working but have issues with the attack and release switches. Luckily I was able to procure NOS of those. the third unit works but there is a 3dB gain difference between channels at gull volume. I had to put them down for a while as I got slammed with work but I can assure you most of the issues I was experiencing were resolved with doing ye old recap.
There is also a cleaner schematics if you need them.

 

[phantombox]

Any idea where I can get this cleaner schematic?

 

[analogguru]

Maybe from an oculist ?
For me is clearly visible in the mentioned "unclean" schematic that IC9 and IC24 are a CD4069UB and that IC5 is a CD4017. Also that the "empty IC-Socket" is a (jumper)-HEADER.

 

[pucho812]

Any idea where I can get this cleaner schematic?

the tech docs section. that one is legible

 

[Niksin]

Power on pins 7 and 4 is standard for single opamps in DIP8 packages.

https://www.soundtronics.co.uk/images/detailed/23/Ext-2240-081.jpg
That being said, there seemed to be some knowledgeable members posting in this thread not long ago:

https://groupdiy.com/threads/bss-dpr-402-service-manual-request.79546/unread

 

[pvision]

There are a number of versions of the DPR-402. AFAIK one has dbx (2181?) VCAs on a plug-in board and early versions have a discrete transistor version. Many were used live so have been bounced around a lot and they suffer from problems with switches & pots. Early versions were also pin 3 hot and prone to blowing output transistors when shorted. BSS stopped supporting them quite some time ago