Optoisolator (tremolo bug) orientation

[Bob M.]

Hi all,

I've got to put in an optoisolator (tremolo bug) in a Fender amp with tremolo today but I forgot the orientation of the 4 leads. The amp came in with old (bad) one already removed, so I can't just copy it.

The one I have as a replacement has 2x brass/copper leads and 2x silver leads. Can't remember if the copper leads are closest to the pots and the silver leads are closest to the tubes or vice-versa.

The LDR seems to be on the silver leads. Of course, I've got a document re: tremolo issues (Fender Service Bulletin), which I've temporarily misplaced.

Thanks for your help,

Bob M.

[nevetslab]

Hi all,

I've got to put in an optoisolator (tremolo bug) in a Fender amp with tremolo today but I forgot the orientation of the 4 leads. It came in with old (bad) one already removed, so I can't just copy it.

The one I have as a replacement has 2x brass/copper leads and 2x silver leads. Can't remember if the copper leads are closest to the pots and the silver leads are closest to the tubes or vice-versa.

The LDR seems to be on the silver leads. Of course, I've got a document re: tremolo issues (Fender Service Bulletin), which I've temporarily misplaced.

Thanks for your help,

Bob M.

I thought I had a full photo on this Deluxe Reverb where I had tweaked the leads for V5 for minimum ticking. It's the stock Fender 'bug', and the copper leads are nearest the tube wires, putting the silver wires nearest the controls.



I thought I had some other images, but none were close-ups of the Tremolo bug. On the Parts Placement diagram of a Twin Reverb, the LAMP is on the tube side, and the LDR is on the controls side.

[Bob M.]

Hi nevetslab,

Thanks very much for your timely help. I have some tremolo info that I misplaced so it was great to get your quick response so I could get on with fixing the amp's tremolo.

Regards,

Bob M.