vibrato not working

[downeyst]

i have a suitcase with a  FR7710 amp,

The sliders and volume knob work fine. the vibrato dosnt work.  When i turn the speed knob to the max speed position the led light above "vibrato on" will turn on briefly, the go off.  I get no vibrato effect at all

Will the vibrato work through the 5 pin cable alone?  I am still somewhat a newb, and after reading the posts for a day i feel more confused.  Do i need to have working speakers in the cabinet to get vibrato?   Right now i have just connected the headphone output into my computer and i can hear audio just fine.

I removed the speakers inside the cabinet, they are pretty damaged but few of them still produced sound when connected.  I have no need for the speakers, i will just use my monitors on my pc rig, not sure if this is the correct thing to do.  I assume someone will tell me to get one of those external power suppplies that sell for 160, id rather not have to buy one if i dont need it.

I tested the accesory loop with a guitar pedal and it worked fine. I just sent it from accessory 1 to 2 on the preamp.

will vibrato only function by connecting the accessory into the amp in some way? i feel confused on the way it is supposed to be connected. 

I pulled out the cards on the amp and checked the solder points on the bottom as said to by a video i saw by vintage vibes.

I took out the preamp and everything appeared ok.  Is there a capacitor on the preamp or somthing which i may need to test, or switch out that controls the vibrato.

again, sorry if i missed explination in earlier posts, I find it hard to search these forums and follow what people are refering to when most the links or pictures are broken.

thanks.

[Rob A]

Your preamp is powered from the suitcase bottom using the 5-pin cable. That one cable carries power to the preamp and signal back out.

You ought to have 1/4" inputs onthe amp that would work for testing the suitcase bottom--there are two channels, two speakers per channel, so hooking a CD player or something up to the jacks is effective at isolating problem to the suitcase bottom.

The vibrato mechanism is inside the preamp, and draws power from it. It's independent of the FX loop, which is purely passive.

I'm not as familiar with the five-pin preamp (I have the four-pin) to comment on likely things to be broken, I will let other members fill in the blanks for you there. On the four-pin model there's a light bulb that drives the tremolo circuitry that is changeable and often fixes issues. Not sure if the same mechanism is used in the 5-pin.