sccloser
Well-Known Member
yeah, I'm an 800 guy, and the jtm seemed to work for me.
it looks pretty clean, like i said, not much discoloration anywhere i can see, BUT, i do have a problem, the heater cct pops 6.3A SB fuses. and i believe the bridge is the cause.
when i power up it peaks at 12A and then settles in at about 4A+ with all tubes installed. im pulling 2+ amps with just the pre's installed, which seems high.
my power tubes are good, no shorts. those pre's should be pulling only about 500mA total correct?
anyway, my tubes are ok, tested for shorts, no probs, so the only other thing it could be is the bridge. im going to swap it out on monday and mount it to the chassis on the power transformer side with some service leads. that should take care of that for a good long time.
plug your guitar into the effect return, do you have sound?
also, are all of your tubes heaters lighting up when power is on?
if your mains fuse is blown, you wont have power lamp, but if your heater cct fuse is blown, it will power up from the mains, but your tubes wont be lit. that fuse is a 6.3A slo-blow, internally mounted.
you can also try jumpering the effects loop with a patch cord, also cleaning the speaker out jack and work the jack in and out a few times.
do one thing at a time so you know what it is if it comes back during one of these tests.
as ive been poking around in mine, i found that if the speaker jack is not plugged in, the power tubes cathode to ground connection is not made. this is a safety feature to prevent blown transformers if you accidentally forget to have a speaker plugged in i would assume. so if you have a meter and know how to use it, you can check for cathode to chassis gnd continuity. you have to have the chassis removed for this check and a speaker plugged in. i noted this when i found it, as the symptom willl be no output, but all other systems will check out fine.
yep
i just had that problem with mine, kept blowing em. i changed the bridge rectifier, and although it didnt seem to make any change on my measured current draw, im not popping fuses anymore...i havent really reconciled why or how that is yet, but time will tell if it comes back or not.