Kung di ako nagkakamali, yung nasa left side ng nakasulat na v2 (yung may glue stick) yung nag lu-loose sakin, saka parang mejo tunaw yung plastic. Sinaksak ko mabuti sa slot tas nilagyan ko ng mighty bond, solb problem ko regarding volume drop. Sibukan nyo kalasin, tas saksak nyo guitar, strum nyo tas galaw galawin yung sinasabi ko using screw driver. Warning!: nung kinamay ko, nakuryente ako ng malupet. Sana same din ng sakin yung case nyo. 
Nakupo seems risky to me. I don't want my bare hands yanking and pulling near the circuit board with the amp powered on.
Takot ko lang. But it's good you found your issue. Loose ribbon connectors lang pala.
Sad news about your Cub amp Sir Siore. 
Hope all goes well with the repair, and that you'd be able to post your repair pics here for future references.
All is well. Here's the short report on my cub repair. I hope it's concise enough..
For first time Cub owners, there is this well-known issue of the amp suddenly powering down. It's been mostly attributed to the poly switch, aka:
thermo switch
polyfuse
thermal fuse
PTC fuse
little yellow devil
thermal resistor
thermistor
These things, like most electronic components, are made in China, and it seems a defective batch found itself into a good number of laney cub amps. Cub10 and Cub12 are the usual victims.
DISCLAIMER: Tube amps can kill. May stored value, teh filter caps. 450V rating, it sez. If you haven't done this before, don't be stooopid. Call mang raul.
First things first. Fire her up, see if it goes to shut-off. Check. Try some good spare 6V6's. Check. Still shutting down. Try good spare 12ax7. In V1 position. Check. Still shutting down. In V2. Check. Same deal. Conclusion. The little devil has to go.
Remove chassis, two screws on top, two at the sides. Disconnect spade connectors from speaker. Push tiny tab to release.
Take care not to touch anything inside. Set on table. Piece of wood helps so chassis doesn't rest on the tubes.
Discharge caps. One end of an alligator clip wire goes to ground point near PT.
Other end goes to plate of most accessible tube, I use pin 3 of V3. Pwde rin sa pin1 ng mga 12ax7. It stays as long as practical. 10seconds is probably enough.
Disconnect PT and OT ribbon connectors.
Remove tubes. 6V6 clamps and bolts as well.
Dislodge main board from plastic standoffs. Long nose pliers can help. There's three. One near OT.
Near PT
And the last tricky bit at the back.
Dislodge board to access remaining ribbon connectors. Remove and take note of their positions for later re-assembly.
All that remains is that pilot lamp. After removing the red jewel on top, loosen (luwagan lang) the nut underneath,
Then while holding the nut, unscrew the top portion. Long-nose pliers helps.
Once you have the board in your hands, madali na lang. Take out Little Nicky by unsoldering underneath. Solder back replacement.
In my case, a piece of ga22 solid core wire.
Now at this point I want to caution, technically you should get a PTC fuse with holding current of 6A, shutoff current of 10A, rated at least 16V. However, other users report that a "bypass" or piece of wire is perfectly fine. Check it out for yourself. At the very least, if i can get my hands on a replacement, uulitin ko lang yung procedure. I will remove the wire, then put new PTC in.
Now. Put everything back. Remove alligator clip (very important). Hook up an 8-ohm speaker to the extension cab jack. Power on. Check check din ng bias kung may time.
.png "lol")
Schematic calls for -21V.
It doesn't go to that shut-off state anymore. No red-plating. Happy tubes.
Power down. Discharge caps again. Replace chassis into the combo shell. Don't forget to hookup your speaker. Done.
And here again is the yellow part causing cub owners worldwide headaches.
You can see part of the schematic where it is located (F1 or LANEY PN = 007390, near the hum adjust). Some users indicate that most amps (or other amps they own) don't have this fuse and question its placement in the design. Others report that after replacing the PTC, they still experience the shut-off issue. Others then again, instead of a bypass, report they opted for the typical short glass fuse, rated 8A, to replace the PTC. So in this case, YMMV.
