As the other gentleman said, there is a cap that will be causing a delay.
Their are MANY revisions of the 225 series of amplifiers, but only a couple electrolytics in each one.
Usually, you find 2 to 3. 1 or 2 of them will be across the 12 volt input wires. They are their to keep LOW freq oscillations out of the power wires, and to keep high freq bleed to a more limited extent, from making it to the power wires. LEAVE THESE ALONE!!!! You will know you have found them because it will go from the red leads (positive) to the ground leads. Period.
THEN, near one of the relays (usually the one by the input side), you will find ANOTHER blue capacitor, standing up 9 out of ten times. THAT'S your SSB delay cap.
Don't use SSB, clip it out. Use it infrequently, clip one side, install a switch in series, and that becomes your SSB / AM switch.
RECENTLY, on the 225 and 300 boards, I've noticed a spot on the front for a SSB delay switch. Check near the wiring for the other two switches, you might find a couple solder pads marked SSB or DELAY. Their will be a jumper across them. Delete this jumper. That kills SSB delay. Install a switch, that gives you AM/SSB.
Hard to give real step by steps without pictures, considering their has been probably 15 revisions of that amplifier since it appeared in the early 90s... As well as having boards mfg'ed in 5 or 6 different countries. BUT, these generics should get you where you need to be... If not, then get your hands out of the amp.
--Toll_Free
--Toll_Free