Blues deluxe--issues

[Valvehead]

i have a Blues deluxe ri here and it has very very low volume , and stuck on ch. 1 , and the led wont light up

ive cleaned the fsw jack ,
pulled the pcb and found no cracked joints

testing U3 im seeing this -

pin1 +16v
pin 4 -16v

pin 5 0v

pin 7 0v

pin 8 0v

R91 does not have 16v

the led has 0v

possibly a diode feeding the chip ? or the chip itself ?


also all tubes are new

[g1]

One end R91 must be connected to the 16V line. Sounds like it is not.

[Valvehead]

thanks--ill check that.

i took some more readings right before i read your post =

U1 pn 8 has 0v , should have +16v ?
pin4 has -16v

anode of D13 should have +16v ? it has 0v

[52 Bill]

Whenever I get one of these I check the usual suspects, the large 5 watt dropping resistors for the 16 volt supplies. Even if you get readings the resistors could still be cold soldered. Try pushing or pulling on the leads and see if the voltages will come back or if the lead pulls out of the board.

[Valvehead]

Mr Bill for the win !

it was a bad joint ---r79 ? to R91 . The bottom of the pcb looked good , but i didnt notice the top of that 1 hole was empty of solder .

amp works perfect now .

Thanks boys !!

[TimmyP1955]

Something else to look at on "Hot" amps is the channel switching and more gain LEDs. The circuit function depends on the LEDs working.