Need to repair JVC 4VN-880 @ London

[yamraj17]

Hi,

Please let me know if anyone can refer a good place to get my JVC 4VN-880 checked in London. It's a recent purchase - when switched-on, the lights come on, but no music comes out. The person who sold it to me referred me to the person who he bought it from, who in turn confessed he didn't know much about the amp. It looks like it's never been used - immaculate condition and I'd really like to get it started asap.

Thanks in advance!

 

[surteess]

I have 2 of these - it is likely to be the over-current protection relay (which is located on one of the plug-in daughter boards) - either the relay has no voltage applied, due to current protection or the relay coil has voltage on it, but has gone open-circuit.

Check to see if the relay coil has voltage on it - sorry I forget what voltage (maybe someone else can tell you).

If voltage is present, then disconnect unit from mains & unplug the relay board (undo 2 screws holding the top cover and pull pcb up) - measure resistance of coil to check that it has not gone open-circuit. If no reading then it needs to be replaced, if there is resistance, then the problem is on the 4 identical pre-amp plug-in boards.

The quiesent current on each board needs to be setup (I did this by changing the fixed resistor with a pot of similar value).

http://www.electronic-circuitry.com/e/action/ShowInfo.php?classid=40&id=246406

http://www.vintageshifi.com/repertoire-pdf/Jvc.php

https://www.google.co.nz/search?q=4...hWDVZQKHfcKC68QsAQIKQ&biw=1664&bih=1137&dpr=1