Been lucky enough to bag my first grail from another forum member (thanks Lee!!!!) on a good deal as it needed a bit of attention.

I think I've read every JVC M70 post on both forums (I'm an info junkie who likes to know what he's doing!) and I reckon its down to a slider needing refurbishing but I want a second opinion before I do any stripping of the sliders.

Its in brilliant cosmetic condition (apart from a cracked tape door) and I've already stripped the unit down and given it a really good clean inside and out and resprayed the grills.  Cleaned the hell out of all switches whilst I was in there.  Tape runs perfectly and everything works well but the right hand channel is very weak whilst the left is good and loud.

The vu meters match the speaker response i.e. the right one is low and the sound through the headphone socket has the same problem on the right.

If you move up the right volume slider the volume increases (still really quiet though) until you get about 80% up the dial then the volume decreases again.

Response from the bass and treble sliders are spot on and all other switches work fine.  The low volume is unaffected by moving any other switches and is the same on tape and radio.

I think this is a case of the right volume slider having a fault within it and I understand from other posts that it is likely a minute crack that can be repaired using silver conductive paint applied very sparingly.  I've already got the stuff from Maplins and am ready to go but I don't want to start without the go ahead from the very knowledgeable 'doctors' on this fabulous forum!!

Can't believe how good this thing is even on one channel so can't wait to be blown away in stereo!

Come on Docs, help me out!

I actually used a pencil and laid down a heavy track to cover and fill a crack. After a few months it is still working. Didn't cost me a thing, have many pencils. I didn't try the silver paint from Maplins but I will keep it in mind if/when mine conks out again.

http://www.4jvc.co.uk/          volume slider here ,  make sure first that the issue is the slider pay attention to the record switch give it a good clean and a blast of air as with the other switches .          stock number 5031-6887-4121-8

there you go si,the doctors are in the housei can only agree with all of them as its a very delicate operation,and all i can say is take your time,theres no rush,and weve all got our fingers crossed for a positive result buddy

Maxx134 is right, you need to try and bypass the iffy slider to prove it is to blame. I would try and work out how to "jumper" the slider to try and ensure that is the problem. There are a million and one other things it could be but the symptoms you describe certainly point at that as being a prime possibility.

If the slider is the problem I would probably go with a new slider as Del points out instead of trying to repair it.

Before you jump in though just try and do a little more investigation into isolating the issue. Check the service manual, where the audio passes across the volume slider and try and work it out from there.

Thanks for all the comments!...I can't do this without you lot, so thanks!

Bit concerned about trying to jump the slider as I am distinctly lacking in electronic skills  so please don't over estimate my abilities in this area!  Up until a few months ago I'd never even opened a box never mind tried to fix one.  I'm confident with stripping down, rebelting, sorting out the notorious gooey Sharp capstan etc but I have zero experience of electronics...I can only solder because I can make stained glass windows!   If I have a confirmed diagnosis I'll very thoroughly research the specific fix and get it right (hopefully) but I don't have the much wider knowledge needed for diagnosing properly.

I don't have a multi-meter and I don't have a clue about schematics so I'm concerned about causing other issues by blundering around.  I've got the service manual, which was invaluable in stripping it down as it wasn't obvious at all like the Sharps I've worked on, so I'll have a look tonight to see if I can work it out.  I assume you're talking about running a wire between the 2 appropriate points to bypass the slider and go for full volume.

I'll also have a look at the replacement slider though I thought from what I'd read on the forums there wasn't one available?

I'd need a multi meter to check for iffy solder joints but I don't want to spend much on one...I've seen loads on eBay for around a fiver...are these any good or a waste of time?

Thanks again everyone!

Simon

yeah i have bought a few bits and pieces of them waited a couple of weeks , same with sharp.

Finally got around to starting on the slider fix! Have very carefully disassembled and have managed to get the tonal board out without destroying anything!

Was all set to remove the slider but realised I've lost my solder sucker so have had to put everything on hold again and order a new one! Will only take a couple of days and I should have my new multimeter by then as well so I can check the resistance properly!

Anyway, so far so good!!!!!