Weak tremolo

[drewl]

Got a blackface Deluxe reverb with weak trem.
The oscillator circuit seems fine, would the roach cause this?
Any other usual suspects?
thanks.

[Amp Kat]

Could be the tremelo cap. Which model is it ? If it has the neon and thermistor see if it's blinking when you turn the speed and intensity up.

[drewl]

Twas the roach.
It was blinky blinky alright, but had a high resistance on one side that measured about 60k on a good one borrowed from a Twin Reverb.
popped the good one in and it works nice.

In 20+ years of amp fiddlin' it was my first bad roach in a Fender...of course it is a 40 yr old amp!

[Amp Kat]

Sometimes you can ohm out that thermistor I think it should be about 120 ohms. Check both and you could use it for a reference check. I haven't seen to many of them go either when they are blinking right.

[Jerry]

Isn't that a photo-sensitive resistor? IIRC the max resistance is usually around 2 Megohm. I don't remember the minimum resistance.