PT 1202-55 Marstran
OT 784-103 Marstran
getting B+ 365 standby switch
getting 388 at pin 3 of power tubes
bias current at 1 ohm resistors 180 power tubes will start to
replate after short time.
new jtm 45 trouble
Moderator: VelvetGeorge
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tooloud
- Senior Member
- Posts: 208
- Joined: Wed Nov 03, 2004 10:16 pm
- Just the numbers in order: 7
- Location: richmond,Tx
new jtm 45 trouble
Last edited by tooloud on Tue Oct 16, 2012 4:25 pm, edited 1 time in total.
"Bend it till it sounds good"
18 Watt TMB Head
JTM45 clone
Metro 69 100 Watt
50 Watt Ceritone metro mix
2X12 Straight & Slant Stack
4X12 V30's & G12H30's
BF Champ
18 Watt TMB Head
JTM45 clone
Metro 69 100 Watt
50 Watt Ceritone metro mix
2X12 Straight & Slant Stack
4X12 V30's & G12H30's
BF Champ
-
neikeel
- Senior Member
- Posts: 7231
- Joined: Tue Dec 06, 2005 8:31 am
- Location: Suffolk, England
Re: new jtm 45 trouble
1) Is your bias circuit grounded?
2) Check the ground on your output socket
3) That PT would normally have a 150k or 180k resistor before the diode
Oh and your bias caps are back to front!!
2) Check the ground on your output socket
3) That PT would normally have a 150k or 180k resistor before the diode
Oh and your bias caps are back to front!!
Neil
-
tooloud
- Senior Member
- Posts: 208
- Joined: Wed Nov 03, 2004 10:16 pm
- Just the numbers in order: 7
- Location: richmond,Tx
Re: new jtm 45 trouble
bais caps were in backwards.... bias current correct now.... B+ now 422
"Bend it till it sounds good"
18 Watt TMB Head
JTM45 clone
Metro 69 100 Watt
50 Watt Ceritone metro mix
2X12 Straight & Slant Stack
4X12 V30's & G12H30's
BF Champ
18 Watt TMB Head
JTM45 clone
Metro 69 100 Watt
50 Watt Ceritone metro mix
2X12 Straight & Slant Stack
4X12 V30's & G12H30's
BF Champ
-
neikeel
- Senior Member
- Posts: 7231
- Joined: Tue Dec 06, 2005 8:31 am
- Location: Suffolk, England
Re: new jtm 45 trouble
tooloud wrote:bais caps were in backwards.... bias current correct now.... B+ now 422
Neil