Looking for Schematic for "Divided By 13" Amplifier JRT 9/15

[alsetalokin4017]

Lining up to try to repair this fine-looking guitar amp and looking for a schematic. Any help would be much appreciated. Amplifier apparently doesn't put out full volume, according to customer.

http://www.dividedby13.com/jrt915.html

 

[alsetalokin4017]

Never mind, I fixed it!

Now that I have it open I can see that it is dead simple in design and built like a tank. I could sketch the schematic in ten minutes but no need at this point.

Symptom: very very weak volume output, somewhat distorted
Prior work done by customer: preamp and power amp tubes swapped with known good, no effect on problem
Procedure: Check filament and plate voltages with Fluke 87-III DMM. inject sine wave signal at input jack, trace with trusty Rigol DS1054 scope.
Result: Voltages good, plate voltage supply at a bit over 300 V. Injected signal goes wonky after volume controls and at intermediate ECC83S/12AX7, looks like a diode-clipped half-sine.
Interpretation: Half of the 12AX7 is dead, receiving no plate voltage.
Action: check resistors in plate supply with DMM. Shoe enuf.... 220k series resistor to dead side's plate is open. Unsolder, check to confirm: open.
Repair: replace resistor and test: WOW, what a beaut! Full volume restored, distortion gone!


Although the bad resistor wasn't burned or had any evident external damage, and was probably simply a manufacturing defect, I still suggest preventative maintenance: Replace series resistors on both plates with higher wattage units.

Note that I really didn't need the scope for this repair. Simply checking plate voltages at the tube sockets with DMM revealed the lack of voltage on the plate, even though the supply was good upstream, and from there it's a single step to check the resistor.

 

[finom1]

Hello, do you have a schematic for Divided By 13 amp? The link does not work. Thank ou!