HU remote circuit, what is this 2R2 SMD?

jol50

Member
2007-11-08 2:14 am
I got this $5 garage sale HU as I need a CD HU for testing....plug wires were messed up and CD did not work, but I got it all going except the remote wire does not work. Only get some mv out of it and 95% sure that is remote circuit as it is only one left that goes to power source and inside it has blue (remote) wire written by connector. It is an Aiwa CDC-Z127.

This SMD appears to not let power through. I think it is a power inductor? I think remote is good for 500mv and assume maybe this is torched? Well I can't find one like this and none this size that best I can measure is 4.8mm x 2.4mm. Actually I don't care what goes in there, it can be ugly I can wire another component to it even. Is 2R2 = 2.2uH?

[IMGDEAD]https://usera.imagecave.com/sho305/aiwaremote.jpg[/IMGDEAD]
 

jol50

Member
2007-11-08 2:14 am
When I searched the 2R2 came up 'power inductor', not knowing SMD I did not think resistors had letters:xeye: But obviously that is why I did not find anything like that. Did find some tiny SMD inductors, but they are not that thin. I really need a non-valuable CD HU to test with and this will be perfect, thanks again Perry. Maybe a good idea to fuse the remote lead, it is missing.

Oh I see, R803 not L803 didn't even look....yes should have known.:sorry:
 

jol50

Member
2007-11-08 2:14 am
It has half the fuse holder on it, I may have another and a 1/2A fuse will have to dig around or will get one.

The other JVC HU I have does not spin the CD not had time to mess with it again...may be a lost cause; is not something I know much about other than checking motor for power and that will be difficult to get at. However, not like I want to actually buy another HU to test with. Don't have a spare home unit for that use either.
 
This resistor in series with the remote lead is intended to prevent a major disaster like blown PCB tracks in case someone puts it to ground or overloads it, which is what they probably did. Don't heasitate to replace the resistor, if you don't have SMD use a straight 1/8W or 1/4W thru-hole type. The bad news is that the transistor that does the remote switching is probably blown too, so you are likely to have 12V there all the time. It's likely to be a SMD PNP part, so be prepared to replace it ;)
 

jol50

Member
2007-11-08 2:14 am
There is two to220 transistors there, I will check if it goes on/off can't remember if I did. Does have 12+v on other side of it when on. As I recall there are no SMD on top of board, new resistor has been ordered. Don't think I have any 2.2ohm unless I cobble some .5 ohm together I'll check.
 

jol50

Member
2007-11-08 2:14 am
Everything works fine but the remote. It looks to go right to the TO-220s and has B+ to that resistor, and continuity there to the remote pin on plug. Well actually some mv to pin.

12v stops at top of R803 in photo. Lets see if this works, I have a red crayon here...
[IMGDEAD]https://usera.imagecave.com/sho305/aiwaremotecircuit.JPG[/IMGDEAD]