Installing the Captive Nuts into the Chassis
Step 1
– Identify the four mounting holes on the outwardly bent
flange edges of the chassis, two on each edge.
Step 2
– With a 5/16” drill bit, enlarge all four of these holes and
remove any burrs.
Step 3
– Place the chassis, flange down, on a flat solid surface
(concrete floor is good).
Step 4
– Place an inset nut on the flange directly over one of the
newly drilled 5/16” holes (photo 5.1a).
Step 5
– With a few blows from a hammer to the top of the insert nut, seat
the nut firmly into the hole and flush against the chassis flange.
Step 6
– Inspect the nut to insure it is well seated (photo 5.1b). Repeat step
5 as needed.
Step 7
– Repeat above for the remaining three nuts.
Installing the 1/2” Grommets
Step 1
– Press the two 1/2” grommets into the two appropriate chassis holes on either side of
the output transformer mounting position making sure the grommets are fully seated.
Installing the Power Transformer
Step 1
– Twist all the wires of the power transformer loosely together and insert
them through the square chassis mounting hole.
Step 2
– Position the transformer in the chassis with the red and yellow wires
toward the back of the chassis and the black and green wires toward the front.
Step 3
– Seat the transformer against the chassis and install three
appropriately bent #8 solder terminals (photo 5.3a) to three of the four transformer mounting
bolts (see wiring layout on pg 53 for which three bolts). Arrange these three terminals so they
are pointed in the directions as indicated on the wiring layout pg 53.
Step 4
– Install a #8 standard nut on each of these bolts and firmly tighten. Make sure that
the #8 solder terminals remain in position while tightening.
Step 5
– Install a #8 KEPS nut on the remaining transformer bolt and firmly tighten.
12 TubeDepot.com
5.2
photo 5.1a
5.3
photo 5.3a
NOTE
There are several great modifications that are possible on this amp. I recommend
reviewing these mods prior to beginning the following assembly steps to see if there is
something that interests you. It is easier to install most modifications during initial
assembly than later.
5.1
MOD
If you want to expand the potential range of rectifier tube selections beyond the stock 9 pin
EZ81, now is the best time to enlarge the size of the present rectifier chassis hole to accept
an octal socket. See “Cool Modifications”, Chapter 11 for more information.
photo 5.1b
5
WARNING
During all drilling and cutting operations, it is important to wear proper eye protection and
follow appropriate safety precautions.
Chassis Preparation
and Assembly
