smallstone issue J clone not working

[gez]

So: Get myself an IC socket, connect a 15k (say R3) res to pin 5 of the socket and V+ to that.
Also connect a 10k (say R1) res followed by a 33uf cap (c1) to pin 4.
Then measure voltage between pins 2,3&6 to pin 4?
Have I got it?

More or less.  Connect a separate 15k resistor (not critical, can be slightly larger) between pin5 of one socketed chip and V+.  You need a divider to bias the chip, so something along the lines of what is shown in the schematic is ideal, i.e. a 15k and 10k in series across the rails, the junction of these two resistors acting as the bias point (Vbias).  Just copy the first 'wet' stage (IC1) as shown in the schematic (though you don't need to include the caps).  Measure pins 2,3,6 and 5 for each chip then swap in another chip and do the same.

If they bias up ok then the problem is with the LFO.  I have a nasty feeling that they're all damaged though...

You could probably do all the above 'in circuit' but it's a lot of mucking about.  You can buy mini breadboards for just a few quid (lot easier).

[nathan Dodd]

i'll get myself a breadboard on the weekend! this is going on the shelf for now i think - i'll post again once i've tested. i did have a pic to show you if i'd got the idea but my PC won't allow me on specific sites I.E a site to upload pictures. grrr

[nathan Dodd]

is this what i need?
http://spidermunky.myphotoalbum.com/view_photo.php?set_albumName=album01&id=tester

[nathan Dodd]

sorry for the shite drawing lol

[gez]

Just edited above quickly so hope it's right...


http://hometown.aol.co.uk/Gezpaton/untitled.bmp

I've whittled it down to the bare bones (all you need for checking how it biases up).

[nathan Dodd]

i'm with you - i'll do that! thank you