New Suitcase Owner - Help

[WurlieNewbie]

Hey guys. I just got lucky and got my hands on a beautiful 1972 suitcase with a peterson preamp. I have two questions:

1) The vibrato isn't stereo panning and sounds more like a mono vibrato (the sound is going in and out as opposed to left and right). To test the speakers, I unplugged the peterson preamp and plugged in headphones into the speaker cabinet and plugged in a guitar to both external amplifier inputs on the cabinet. For input #1, I heard the guitar in my left ear. For input #2, I heard it on the right. Am I right in assuming this means both channels/speakers/amps are working correctly? Is the culprit most likely the peterson preamp and one of those pesky bulbs that's tied to the vibrato?

2) This model doesn't have an FX loop and doesn't have extra holes drilled into the rail to accommodate one. If I want to install a loop into the peterson preamp, will I have to drill into the rail AND the harp cover since the space there is so tight? Anyone out there have any experience with this and can offer tips on how to minimize the damage?

Thanks!

[sean]

1.  Yes, it appears that both amp modules are working.
2.  Shouldn't the Peterson have the effects loop in the speaker cabinet?  Some did.

Sean