The amp has been checked out, first, ESR checks (for a quick check of the electrolytics before powering on.. initial power-up with a PR57 isolation xfmr/variac increased slowly over the course of more than an hour.. since I didn't know how long it's been since the amp was actually used. Voltages have been checked with 2 6N3C tubes in place (originals are
6l6GC).. 475, 470, 6.25VAC, and -55.I first powered the amp in Standby with no tubes, and checked the operation of the preamp with a speaker plugged into the Preamp Out jack, and also the Line Out jack.
Several pots (12 total) were intermittently open while turning (even though I'd tried to get DeoxIT paste into them, which is somewhat difficult). Getting liquid DeoxIt into the openings was a matter of propping the chassis up at an angle where the liquid would drip off of a needle tip into the opening so it would migrate back into the pot.
The orientation of the openings on the pots make it difficult to get a little DeoxIt paste into the pot cases so the wiper can pick it up and wipe it across the track, and the pot shafts were hard to turn, indicating that any original lube was likely very stiff (30 years old now).. but I also suspect that the open state was poor contact between the wiper and the fixed center terminal (typically a ring around the shaft that rides on a stationary contact that is part of the center terminal).
The Reverb circuit isn't working, although I can hear echo sounds from probing pin 3 of (IC) U6, and thumping the spring box produces loud echo. The test setup is included with the schematic, so I'll get around to checking the missing reverb. The Phaser/Rate and Color circuits are operating normally.
The schematic shows the tube designations V1-V6, and just 2 used tubes were installed into sockets for V1 and V3, and the amp was operated for more than an hour, from the Main Output (8 ohm) into a vintage 12" Utah Celesta tri-axial speaker without any problems (low to mid volume levels).. sometimes fed/injecting 1kHz tone, and also playing a guitar thru the various inputs.
The full schematic with board images can be found here (many other models, too): peavey mace deuce vt [2 MB]
Also an extensive list of semis and replacement part numbers: peavey semiconductor cross reference list [117 KB]
The differences between the Deuce and the Mace are clearly shown in the 4 pages of the info. The power output section of the Mace VT series is wired differently from the
*Mace A series* model, which I'd commented on earlier. The Mace VT model utilizes separate 100/5W resistors for each tube's screen grids (pin 4) and separate 47k resistors for each tube's control grid (pins 5).I found numerous suggestions to replace the screen grid 100 ohm/5W resistors (pins 4) with 470/5W, and to replace R1 400 ohm/10W resistor (500V source) with a choke. I may try this fairly easy modification after using the amp for a while.
-- Cheers, WB .............