I have bought a nice working JVC RC-X610 and as an electronic engineer I plan to add an extra input for connection to a my SmartPhone's audio o/p jack.

Presently, the X610 has a CD Out (RCA) and a 3.5mm labelled MIC/MIX but which appears to be, if it's working at all, very insensitive. I will repurpose one of these connectors as my new input.

Can anybody point me to a service manual or schematic circuit diagram for the machine?

Tim

read his listing for this model..

http://www.ebay.co.uk/itm/JVC-CD-PORTABLE-SYSTEM-RC-X610-/390356622558?pt=UK_CE_Portable_Audio_Portable_Stereos_ET&hash=item5ae3115cde

JVC CD PORTABLE SYSTEM RC-X610

HAVE HAD THIS SYSTEM SINCE NEW (EARLY

 EIGHTIES FROM MEMORY) AND IT HAS HAD

 SURPRISINGLY LITTLE USE. 

 IT IS IN VERY GOOD UNMARKED CONDITION

 AND EVERYTHING IS WORKING AS IT SHOULD

DO.

 IT DOES PRODUCE VERY GOOD QUALITY

 SOUND WITH PLENTY OF POWER IF

 REQUIRED.

 THE SYSTEM  COMES COMPLETE WITH POWER

 CORD AND REMOTE CONTROL TOGETHER

 WITH INSTRUCTION BOOKLET.

 COPY OF SPECIFICATION FROM MANUAL

 PLEASE LET ME KNOW IF YOU WOULD LIKE A COPY OF THIS INFO. AND I WILL

 FORWARD BY EMAIL

http://myworld.ebay.co.uk/hara...?_trksid=p4340.l2559

 I HAVE TRIED TO KEEP P/P COSTS MINIMAL

 BUT THIS A HEAVY ITEM.

 THANK YOU FOR LOOKING AND PLEASE LET ME KNOW IF YOU HAVE ANY QUERIES.

Thanks, I picked up a scan of the specification but I am after its service manual or at least a circuit diagram of the JVC RC-X610

You may wish to find/source a Pre-Amplifier to ramp up your signal to the input level required for the mic input to make this work.

Since this Radio in NOT a Box as it is Not-affectionately called a "egg" boombox!!! cause of it's shape ( egg-shaped ) it may be Too New to find the Schematic's that you need to do the upgrade's you are attempting to do.?

Maybe you can Purchase this information online somewhere - It's douptfull that Anybody on this 'Site' would have a schematic for this unit... as it's Not a box.... 

I think I've exhausted Google in my search for the JVC RC-X610's service manual. There are a few sites that appear to list the manual but only by recycling my Google query string.

So it looks like my next move is to remove its amp pcb and transcribe its circuit by hand.

I'm surpised you say it's 'not a box'? It's much lighter and, more portable than my sewer-pipe style JVC Boomblaster, and its a little squarer but it looks quite egg-shaped to my eyes!

am Familar with the JVC RV-NB1  as it is as you say; Sewer pipe shaped and it's not very portable and eat's batteries But it Does Boom the Bass I use one for my speaker's for this desktop as it is hung from the ceiling behind me and sound's Terrific

This below; However is Still EGG shaped - Not Tubeular and Not Square.
JVC RC-X610 CD Rounded Football Shape EGG !

Fullsize Rounded Football Shape EGG !!!
http://i41.tinypic.com/t83whk.jpg
Not that I am looking but is there anyplace out there that sell's

this Information that you are looking for?

just got one yesteerday!!!!!!!!!!mine has a vibration issue though right now

Fantastic! Did you see an obvious PCB location to insert a line-level signal on the circuit schematic?

On vibration. Judging by the amount of tape holding the internal wiring in-place there is a lot about the design that can potentially rattle when the volume is up. Fixing that without having to tighten all the casing screws for each de-rattling attempt suggests taping-down *anything* that is movable - Mine rattles too! Good luck.