DaveBerlinetta
New Member
I'm restoring the radio out of my 1985 Camaro Berlinetta. While I have it apart, I'd like to add an audio input jack that would be fed from a MP3 player or Sat radio. I plan to use a set of unused inputs to a MC14052 Dual 4-CH Mux that controls input (radio/tape deck) feed, and use a NC/NO 3.5mm jack to force the Mux to the open channel I'm using.
After the Mux, is an IC that I just can't find any specs for. The Delco schematics show it as a DM-171 DNR. It's a 14-pin DIP, and here's what is listed on the drawings for it:
1 - 8v B+
2 - 4v L. Audio IN
3 - 4v Out FDBK
4 - 4.1v L.Chn Out
5 - 3.1v SUM Out
6 - 0.8v SUM RTRN
7 - 0v GND
8 - 4.5v GAIN Out
9 - 0/1.2v SUM 19Khz *
10 - 3.3v PK DET Out *
11 - 4v RT Chan Out
12 - 4v FDBK
13 - 4v R. Audio IN
14 - 4v BYPASS
* - DNR OFF/ON
I've never worked with an IC like this before. I haven't had a chance yet to put a scope on it, probably this weekend. I can take some educated guesses at the descriptions, but I would really like to see a datasheet. Especially how the DNR OFF/ON works.
I've been searching for about a week now, that's how I found this site. There are no marking outher than Delco's "DM-171".
Anybody work with this chip before?
After the Mux, is an IC that I just can't find any specs for. The Delco schematics show it as a DM-171 DNR. It's a 14-pin DIP, and here's what is listed on the drawings for it:
1 - 8v B+
2 - 4v L. Audio IN
3 - 4v Out FDBK
4 - 4.1v L.Chn Out
5 - 3.1v SUM Out
6 - 0.8v SUM RTRN
7 - 0v GND
8 - 4.5v GAIN Out
9 - 0/1.2v SUM 19Khz *
10 - 3.3v PK DET Out *
11 - 4v RT Chan Out
12 - 4v FDBK
13 - 4v R. Audio IN
14 - 4v BYPASS
* - DNR OFF/ON
I've never worked with an IC like this before. I haven't had a chance yet to put a scope on it, probably this weekend. I can take some educated guesses at the descriptions, but I would really like to see a datasheet. Especially how the DNR OFF/ON works.
I've been searching for about a week now, that's how I found this site. There are no marking outher than Delco's "DM-171".
Anybody work with this chip before?
Last edited: