Amp Mad Scientist
Ambassador of Heresy
nice job
Fender BJr repair
- Thread starter STRefugee
- Start date
OP
STRefugee
Well-Known Member
All wired-up and all. Powered it up and switched it on and Fack all!! Not even the pilot light come on.
Tested the cable to the power socket and it's fine.
Tested the switch and the power flows through from S1A to S2A.
No juice flowing anywhere after that it seems. Testing the caps shows zero V readings.
Here's a pic of my nice useless pcb.
Spent so much time on this F#£@!! Thing I'm totally fed-up with it now. Better move away from it or I may kill myself stupid.
Tested the cable to the power socket and it's fine.
Tested the switch and the power flows through from S1A to S2A.
No juice flowing anywhere after that it seems. Testing the caps shows zero V readings.
Here's a pic of my nice useless pcb.
Spent so much time on this F#£@!! Thing I'm totally fed-up with it now. Better move away from it or I may kill myself stupid.
Amp Mad Scientist
Ambassador of Heresy
Don't panic it's probably just a minor thing.
We can go through it.
Don't try to power it up until we go through and look at everything.
Can you take more pictures so I can see all the connections?
But don't plug the power in yet.
OP
STRefugee
Well-Known Member
Amp Mad Scientist
Ambassador of Heresy
Take a day off and relax.
You are not that far from finishing.
Patience and determination makes things possible.
One bug is not the end of the world.
OP
STRefugee
Well-Known Member
Hi @Amp Mad Scientist,
I followed your advise and took the day off. Cooked a lamb tagine with prunes and lots of good stuff for 6 although there were only three of us round the table. Enjoyed a couple 2019 St Emilion bottles and later visited the local Pub for a chilled pint of Italian lager. Crashed in bed and landed a couple of hours from my Cosmic voyage.
Found the will power to get back into my Blues Jr. and I think I might have a cue as to what may be happening. will send pics and thoughts through here. I think This PCB was not wired as per the schematics for some obscure reason. will explain shortly.
I followed your advise and took the day off. Cooked a lamb tagine with prunes and lots of good stuff for 6 although there were only three of us round the table. Enjoyed a couple 2019 St Emilion bottles and later visited the local Pub for a chilled pint of Italian lager. Crashed in bed and landed a couple of hours from my Cosmic voyage.
Found the will power to get back into my Blues Jr. and I think I might have a cue as to what may be happening. will send pics and thoughts through here. I think This PCB was not wired as per the schematics for some obscure reason. will explain shortly.
Amp Mad Scientist
Ambassador of Heresy
take your time don't panic
OP
STRefugee
Well-Known Member
So here's my take on what may be the reason for there being no juice flowing from the main Transfo to the pcb.
Checked the Switch and when "ON", juice flows out from the S2A lug down the black wire to wj5 on the board. Which then go straight in ( F1) the Fuse. And to lug P4 where according to the schematics, the Violet/purple wire brings thr juice to the transformer.
But that is where things were different. It was the Black & Red wire that was plugged on P4. And the Violet wire was left unplugged. See the pics of schematics and my notes when I pulled the wires off.
So I want to plug the B&R wire on lug P4 as it was previously and see if that powers up the amp.
But want to check with you if you think it's too big a risk.
Also...
Checked the Switch and when "ON", juice flows out from the S2A lug down the black wire to wj5 on the board. Which then go straight in ( F1) the Fuse. And to lug P4 where according to the schematics, the Violet/purple wire brings thr juice to the transformer.
But that is where things were different. It was the Black & Red wire that was plugged on P4. And the Violet wire was left unplugged. See the pics of schematics and my notes when I pulled the wires off.
So I want to plug the B&R wire on lug P4 as it was previously and see if that powers up the amp.
But want to check with you if you think it's too big a risk.
Also...
Attachments
Last edited:
OP
STRefugee
Well-Known Member
Another oddity I came across when re-capping the pcb was the way the cap C34 was fitted.
It is a polarised cap and on the pict (black cap) you can see the neg pole was set on the positive as marked on the pcb. I fitted the new one according to the marking on the pcb.
Do you think this may be an issue?
It is a polarised cap and on the pict (black cap) you can see the neg pole was set on the positive as marked on the pcb. I fitted the new one according to the marking on the pcb.
Do you think this may be an issue?
Attachments
Amp Mad Scientist
Ambassador of Heresy
Hold on don't power it up yet.
I gotta look at this when I get back from the dentist.
and when you power it up don't put the output tubes in yet.
OP
STRefugee
Well-Known Member
Hi @Amp Mad Scientist,
Thanks for getting back to me and offering to look into this, Much appreciated.
I'll wait till you get back to me.
Hope all goes well at the Dentist
OP
STRefugee
Well-Known Member
Amp Mad Scientist
Ambassador of Heresy
Take out the output tubes
Set meter for AC volts highest scale
turn power switch on
See the back of the power switch? There is a top pair of terminals with 2 black wires attached.
The bottom 2 terminals attach to wires are brown and blue.
Turn the switch on and measure between those 2 top terminals with the 2 black wires attached.
The rivets on the back of the switch are exposed metal and you can touch your probes to the metal on the 2 terminals
there should be 220V between those 2 rivet terminals.
If there is no voltage there, measure between the 2 bottom terminals with blue and brown wires attached.
There should be 220V between those 2 terminals when the power is on or off.
Do you get voltage at the top 2 terminals when the switch is "on?"
OP
STRefugee
Well-Known Member
Hi @Amp Mad Scientist
Ok, will do and let you know.
Just occured to me that on the schematics, Blk/Red and Violet wires are shown as in that screenshot.
As already mentioned earlier I had found Blk/Red wire on the P4 Lug and no wire on Lug 7. The Violet wire had been left unplugged.
What is the meaning of the inverted hooks I circled in orange?
Ok, will do and let you know.
Just occured to me that on the schematics, Blk/Red and Violet wires are shown as in that screenshot.
As already mentioned earlier I had found Blk/Red wire on the P4 Lug and no wire on Lug 7. The Violet wire had been left unplugged.
What is the meaning of the inverted hooks I circled in orange?
Amp Mad Scientist
Ambassador of Heresy
the hooks are the fuse, or a fuse of some type.
OP
STRefugee
Well-Known Member
In this shot you can clearly see that the cap C34 was fitted with its neg pole where the pos pole should have been according o the marking on the PCB.
Why would that have been done that way?
And here I show the new one I fitted witth the pcb "+" sign marking clearly in sight.
Why would that have been done that way?
And here I show the new one I fitted witth the pcb "+" sign marking clearly in sight.
Amp Mad Scientist
Ambassador of Heresy
It was a mistake somebody installed it backwards.
OP
STRefugee
Well-Known Member
Yes, there's power.
measured between those 2 top terminals with the 2 black wires attached.
