Effects loop problems anyone?

[kungfujews]

Can anybody help me? I've got a MK IV B short body combo, circa 1993, and I run my Boss DD3 through the effects loop. I generally leave the loop open all the time just to have a mild delay across the board. I've noticed a few problems occuring recently - firstly, the volume has been decreasing severely - the problem would sort itself out whenever I deactivated the effects loop from the footswitch. I thought at first that it might be the pre-amp valve for the loop as after a short while the volume would return when I switched the loop back on. However, when I was gigging the amp last night, it stopped working altogether - no sound at all - and very sudden too... I thought I'd stepped on my lead. The amp was fine when I switched off the effects loop and I was able to continue the rest of the set - albeit without my delay.
I've changed my leads to eliminate that possibility, but I'm a bit worried it might happen again...don't want it stopping in the middle of my solo during Redhouse again! A few questions:
1. If it's a pre-amp valve - would it just stop suddenly - without a cough and a splutter?
2. Will the effects loop valve wear out more quickly if I leave the loop on all the time?
3. If it is the valve - is there a recommended valve for the effects loop?

Hope someone can help me - thanks, and peace.
Jason

 

[Fronzil]

happened to me, contact cleaner fixed it, it was just a dirty input jack I figure (every time I disengaged the loop it was also fine)..hasn't done it since (that was well over a year ago)...literally spray contact cleaner on your cable, and **** that FX loop input with it real good..in and out! if that doesn't work it could be something more serious.

 

[kungfujews]

Hey thanks, I'll give that a go - I'll f*^% that loop like it's never been f&^$*d before!!

 

[Fronzil]

cool, let me know if it works! I'm always up for learning for ins and outs of the IV. one of my all time favourite amps.