Created an mp3 input for SC-816......

k4ro · Post by **k4ro** » 17 Feb 2010, 15:15

I just successfully tapped into the cassette player audio line of my SC-816. Many thanks for the excellent info folks! I soldered one line to each L/R potentiometer on the cassette board, and soldered the shields to ground. Now my iPod is playing fine through the SC-816 when I insert a cassette.

I tried the "dummy" cassette but it would pop out. I guess the take up reel has some kind of tension sensor that ejects the tape before eating it. Has anyone found a way to completely disable the tape motor and/or tension sensor so that the mod will work without a cassette inserted? That would be the cat's meow.

Thanks again for the great info.

Post by **ghoulama** » 20 Apr 2010, 22:01

cn_bryan wrote:lewismug, thx for sharing your invention, you'd done a great job, you have an exact stereo system that i have SC-816, I was seeking a way to plug my Iphone to the stereo and now I found it, thank you!!

but for the safety, i wanna make sure something that you have mentioned above, cuz if anything gos wrong, would probably have to spend more than buying a modern stereo system to repair.

In this step, did you actually pull out the connection board and turn it upside down? cuz we see from below the orders are different.

somewhere in this forum someone posted the solution for his SC-813:
https://www.matthewsvolvosite.com/chat/p ... c&start=40

and I recognized that the SC-813 actually uses the same connection board as the SC-816 does, but he soldered the wires to different pins, and he didn't use any resistor at all.

hum !!! which one should try ...?

i just used bryan's technique pictured here and it worked beautifully on my sc-816

omegapilot · Post by **omegapilot** » 12 Jul 2010, 14:13

Hi guys and thanx for a good fora and a good discussion.

I can confirm that this (lewismugs) connection also works for the SC-815 but I did some minor modifications. First let me say that the round yellow circle is ground in his picture. I measured to the chassis ground. Secondly right and left seems to be switched on the drawn scematic, but this is of less importace and easy to correct.
Importantly is in what case that the red circles around the soldering points in the pic are the correct ones but the drawn schematic is some what confusing (mirrorised, flipped or something?).

Well, to my real issue: At least on my SC-815 with this original 5.1kohm and 1Kohm connection (voltage division) I had to play my MP3/computer at lowest level meaning that the signal-noise level is not very good. I saw that someone had problems with interference... If you add a 20kohm resistor in series just where you connect your cable to the
MP3-cable you will be forced to crank up the volume on your external MP3-player and the voltage in the cable will be grater than small airborn disturbances like cellhone signals etc.

My tip to this already good solution: Add 20kohms-30kohms resistor in series with your connection line (one for L & one for R) and you will get a more solid and noise free signal.

BR Niklas

MyS40T4 · Post by **MyS40T4** » 03 Aug 2010, 00:52

by k4ro » 18 Feb 2010, 07:15
I just successfully tapped into the cassette player audio line of my SC-816. Many thanks for the excellent info folks! I soldered one line to each L/R potentiometer on the cassette board, and soldered the shields to ground. Now my iPod is playing fine through the SC-816 when I insert a cassette.

I tried the "dummy" cassette but it would pop out. I guess the take up reel has some kind of tension sensor that ejects the tape before eating it. Has anyone found a way to completely disable the tape motor and/or tension sensor so that the mod will work without a cassette inserted? That would be the cat's meow.

Thanks again for the great info.

This is a brilliant mod!
I had the issue with the dummy cassette as well. I've made a thin card gasket the same shape as the thin plastic ones in the cassette. I used a business card which is the correct thickness (for me at least). The gasket is fitted inside the cassette in addition to the existing plastic gaskets, to apply tension the reels so the tape deck doesn't spit out the cassette. Working for me!

You may need a second card gasket, but I found it applied too much tension and the tape player reversed play direction (tape player thought it reached the end of the tape).

The other thing I found is that the cassette player circuit board in my SC-816 was different to the one in the pictures (see "cn_bryan"s post ). The pickup points I've used for the cable were labelled with L/R channel and finding the signal ground was easy. Because it's not direct off the tape head as shown in the original mod, the levels are fine with no distortion and there's no need for resistors. Just make sure Dolby NR is off when listening to the iPod and I still need to set the volume lower on the iPod (about a third volume) but otherwise it sounds fantastic. Plus should I want to play a tape I still can...

Cheers,

Chris

mrjacobrussell · Post by **mrjacobrussell** » 05 Aug 2010, 07:25

I was going to buy a mp3 playing stereo..

I did the mod with no resistors on my sc 810... Ill pics latter i went to radio shack and baught a 6 foot head phone to headphone cable with the intention of cutting off then end and soldering it on the pins..

I found a headphone to rca cable that was just as long in the house cut the rca jacs off spun the braded shield (ground ) togeather and soldered it on it works perfect! Audio quality is great i just listend to some lonley island on the way to work. And it almost cost nothing!

I was going to buy a extra mp3 player but found this works well with my blackberry bold 9700 now i have a excuse to buy a huge SD card

next project make a adapter to hook up a mic and use my car speakers for hands free

mrjacobrussell · Post by **mrjacobrussell** » 05 Aug 2010, 23:20

Dietmar wrote:I tried to implement these suggestions on my sc-810 in my 1993 850 Volvo. While accessing the tape deck was much easier than described for the sc-816, the tape deck looked all different...

I ended up finding this post
http://volvospeed.com/vs_forum/index.ph ... opic=79171
and contacted "Owned" for details. Turns out all I needed to do was to find the left, right and ground contacts on the tape deck board. (You can see them in this picture, on the very right end of the board with R to the right and L-CH and S-GND to the left of the contacts below the one for right):

Adding the resistors only reduced the volume, so I removed them again. Also, I ended up connecting the left channel (according to the tape deck board's labeling) to the jack's top contact, not the right one as in the pictures.

Cheers,
Dietmar from Queens, NY

can any one out line the pins im getting right audio but no left

mrjacobrussell · Post by **mrjacobrussell** » 06 Aug 2010, 23:24

ok so it its R for Right, Left is directly below it in line with the l-ch , and ground is G

I couldnt get full volume audio from the left chanel so i removed the pins from the cuircutboard pulled the board out and wired directly to the ribon cable

i now have audio .. im not sure if i had a small short to ground causing the left channel problem but this works now!!

also i removed the spring from the tape deck assembly and pushed the black plastic tab piece in. It acts as if a tape is always inside, ill work on overriding the ejection mechinisim later but for now it works

pohovolvo · Post by **pohovolvo** » 23 Nov 2010, 10:21

Just successfully performed mod, but also found the issue which made me seek this solution. My tape deck adapter was working fine for about a year, when it one day decided to reverse direction several times then eject the adapter. I dont own another cassette other than the adapter, so I hadnt tested it otherwise. When removing the cassette unit from the case, I noticed the band that turns the pullys lying on the circuit below was broken, in addition to its obvious derailment.
With the mod performed, I can Hear the audio sparatically as the reverse mechanism engages /disengages before it ejects and switches to FM.

Has anyone mapped out that cicuit board and can help me hack the signal to sense that there is a working tape?

Also My left channel has always been in and out, I will always have the highs coming from the tweeter on the dash but the midtones are not audiable, has and one else experienced this problem or is it probably a loose connection in the door? Almost seems like a crossover is malnfunctioning.

pohovolvo · Post by **pohovolvo** » 23 Nov 2010, 10:30

Also, the circuit board is different on my SC-816 than all others ive seen posted so when i take it apart again to tinker with it, Ill take some pics and post them, I used a combination of cn_bryan's and lewismug's techniques.(ground placement from the latter.)

Post by **fazool** » 22 Mar 2012, 10:43

For anyone finding this thread via the repair database - I tweaked this procedure and applied it to my 2001's HU-615.

The procedure is similar. I included photos which more clearly explain the solder connections.

https://www.matthewsvolvosite.com/forums ... 33&t=47478

Created an mp3 input for SC-816......

Re: Created an mp3 input for SC-816......