fender blues deluxe reissue stuck distorting

hi,

I have a blues deluxe reissue that is stuck distorting

any guesses based on these measurements? all VDC unless noted. I'm also curious if the distortion is simply stuck on. i only hear one relay click

V1A
plate 197
grid 0
cathode 1.4
B
plate 194
grid 0
cathode 1.4
V2A
plate na
grid na
cathode na
B
plate 207
grid 14mV
cathode 1.2
V3A
plate 194
grid 18.9
cathode 28.7
B
plate 200
grid 19.5
cathode 28.6
V4A
plate 352
g1 0
g2 352
g3 -49VDC
cathode 3.6mV
V5A = same as V4A
plate
g1
g2
g3
cathode
 
D18 is not lit when clean is selected

I replaced the flyback diodes for both relays - even though both diodes tested as good before hand. Still, Im used to being able to hear both relays click just barely off time in these situations. I think I only hear one.

R16 and R11 while in circuit measure 100k ( well closer to 99k.. )
 
Any idea what these mods are? The amp was purchased in 2011
 

Attachments

  • C8D77AB9-C776-443F-9D3F-F8C0D4F49378.jpg
    C8D77AB9-C776-443F-9D3F-F8C0D4F49378.jpg
    189.3 KB · Views: 46
-20dBu program material seems to break up too early. I can't inject beyond said signal level to J4 without undesirable distortion coming from the amp. It still gets loud, but it breaks up in an ugly way and too early. when I turn the level into J4 up beyond -20dBu it gets ugly.
 
Hi


Have you tried the amp with a guitar? Although the nominal level of guitar is -20dB, real guitars have much different signal output. Fender's schemo shows a tiny input signal with specified control settings and a specific output (not necessarily max out).


The switching should work and be obvious that is going from clean to dirty and back again. But... the switching is not simple. The two relays switch together but one is off and the other is on and they alternate. They are controlled by three opamps, so you have to use the schematic and go through the switching circuit measuring voltages. It is easy to see with just a DC volt meter what should be on or off. That is one nice thing about switching circuits is that the voltages are always at an extreme.