Please Help Me Trouble Shoot 64 Bandmaster

[Bruce / Mission Amps]

What's up with the red/yellow pair hanging out in the middle of nowhere in the third pic?

Never mind..... ugh.

[Leo_Gnardo]

So is this what we think is going on in there?

Eggs ackley! Looks like a Fender print too - what is it?

The hi filter of domino cap (value not given in this schemo) & 220K dumping signal into the "virtual" AC ground of the 375V node filter cap. To achieve that "dumpy" tone. Well, somebody must'a liked it.... but not too many because it sure didn't stay long.

[The Dude]

Never mind..... ugh.

The question was asked and answered so it's a bit irrelevant at this point, but you don't think it's a legitimate question to ask why stripped wires are hanging loose in an amp?

[Leo_Gnardo]

The question was asked and answered so it's a bit irrelevant at this point, but you don't think it's a legitimate question to ask why stripped wires are hanging loose in an amp?

Can only guess as to the motive - maybe so they could be reattached if there was a bid for "authenticity" and Bob wanted to do away with the shielded cables? Then the originals are right there. Once the murky-tone circuit is done away with, he might want to do that.

I think Bruce's answer is driven by - it's sloppy looking. Unaesthetic. That's OK. I agree.

I think the shielded went in, in a misguided attempt to solve the amp's problems. Not that there's anything wrong with that - I often find crackly noises associated with the old cloth cable running under the circus board and sub shielded or non shielded plastic insulated cable depending on the hum/buzz level I find. These aren't hi gain amps and shielded cable doesn't really make a whole lot of difference.

This message brought to you by your Department of Redundancy Department. A subdivision of the Veterans Tapdance Administration.

[ReadyTeddy]

There's lots of advice and speculation on this thread--much of it good, but if you want to solve the problem quickly, beg, borrow, or buy a scope and a function generator. Make a resistive load to take the place of the speaker. Now, inject a sinewave of the appropriate level into the amp's input, and while sweeping the frequency over the audio range, trace the signal through stage by stage. First go to the plate of the first preamp tube. Does the frequency response and signal level look as suspected? If OK, probe the plate of the next tube in the circuit. Within 10 minutes (if you're taking your time) you'll find the stage at which things go south. Now, probe at various points in that one stage. Don't forget to check DC as well as AC voltages. You'll narrow down the problem very quickly. This is a simple, logical, and surefire method of troubleshooting. It does require some equipment, but you can spend lots of time and money doing far less productive things.

[Leo_Gnardo]

There's lots of advice and speculation on this thread--much of it good, but if you want to solve the problem quickly, beg, borrow, or buy a scope and a function generator. --snip --- This is a simple, logical, and surefire method of troubleshooting. It does require some equipment

100% right ReadyTeddy, but DAB's not about to go get all these, I'm guessin'.

If we could convince him to just try - lifting one end of the 220K on those murkytone filters - I'll bet Bob would find where his get up & go, got up & went. In a matter of seconds. (Wiping brow, lookin' a bit weary) I'm gettin' a little tired of repeating...

This way, shortcut to sonic paradise. OK pilgrim, take the hard way, but the short cut option is still there. Seconds away. I can only keep encouraging Bob, heat up the iron & give it a go. There's nothing to lose but lousy tone.

but you can spend lots of time and money doing far less productive things.

Wow have we ever proven THAT, Q.E.D. x 10000

[dumbassbob]

100% right ReadyTeddy, but DAB's not about to go get all these, I'm guessin'.

If we could convince him to just try - lifting one end of the 220K on those murkytone filters - I'll bet Bob would find where his get up & go, got up & went. In a matter of seconds. (Wiping brow, lookin' a bit weary) I'm gettin' a little tired of repeating...

This way, shortcut to sonic paradise. OK pilgrim, take the hard way, but the short cut option is still there. Seconds away. I can only keep encouraging Bob, heat up the iron & give it a go. There's nothing to lose but lousy tone.



Wow have we ever proven THAT, Q.E.D. x 10000

The one 220K by V-2 was broken,so it was disconected...But Again Gerald Weber Pulled Out the 220K (R) Pulled out the Domino caps Pulled Out All the Blue Coupling caps and put mallorys in It didn't Help at allthe problem Has got to be some where else...Like why did the bias cap blow 2 or 3 times...Cold a bad bright switch or a pot be the cause...Also GW helper did not even solder the 2nd 500pf cap down...Why is there NO treble,only Bass,Before I would set it ,Volumes on 6 bass on 3 Treble on 3...Now with the bass on zero and the treble on 10 it is just a big pile of mud...I can't belive GW couldn;t fix it..All I want is to have a clean sounding amp again..I have spent over $1,100 and almost 3 years.for nothing...I am saving $$$$$$ up to send it on another trip to Pull out the caps techland..It seems someone can redo the whole board to make it run "clean with some balls"...I don't ever care if the vibrato is pulled out...This was a good sounding amp.

[Tom Phillips]

...I am saving $$$$$$ up to send it on another trip to Pull out the caps techland..It seems someone can redo the whole board to make it run "clean with some balls"...

Arrrrrrrg…WTF Bob! You have had at least two offers from members of this board to do hands on work to fix your amp. Now you want to send it off to another remote shop that will gut the whole board and start over? Now you want “clean with some balls” My dog can clean his balls but it doesn’t help my tone.

You don’t know what’s wrong with your amp and you don’t have the background to fix it. That is not your fault. You did good to ask questions here but then you didn’t take the advice offered. I feel safe to say that I’m not the only member frustrated by that. When someone asks you to do a specific test or answer a specific question it is to help them troubleshoot your amp. That’s part of the process of isolating the problem. What’s expected and what would be helpful is a clear and concise answer to the question. The story of how you have let yourself be mistreated has been sufficiently documented. We don’t need to hear any further rants about that. If you were to print out all the postings in the five different threads you started about this problem and read them in chronological order you will understand what I’m getting at. You can skip the recent posts in the “Pulled Coupling Caps” thread where people have gone on to discuss other topics. That was an interesting morph by-the-way. It’s very similar to what happens at a party when the original leader of a conversation looses the interest of the other participants and everyone drifts away to discuss topics that they find more interesting and productive.

So Bob…DON’T BE A DUMBASS. You picked the name but it’s not required that you live up to it. If you want the original mojo back in your Bandmaster then review the threads and take advantage of all the advice from the experienced and knowledgeable people who have been trying to help you. That advice has been free to you but it did cost the contributors time that they could have spent on their own projects.

The End (of Tom’s rant … for now … maybe)

1010

[The Dude]

Arrrrrrrg…WTF Bob! You have had at least two offers from members of this board to do hands on work to fix your amp. Now you want to send it off to another remote shop that will gut the whole board and start over? Now you want “clean with some balls” My dog can clean his balls but it doesn’t help my tone.

You don’t know what’s wrong with your amp and you don’t have the background to fix it. That is not your fault. You did good to ask questions here but then you didn’t take the advice offered. I feel safe to say that I’m not the only member frustrated by that. When someone asks you to do a specific test or answer a specific question it is to help them troubleshoot your amp. That’s part of the process of isolating the problem. What’s expected and what would be helpful is a clear and concise answer to the question. The story of how you have let yourself be mistreated has been sufficiently documented. We don’t need to hear any further rants about that. If you were to print out all the postings in the five different threads you started about this problem and read them in chronological order you will understand what I’m getting at. You can skip the recent posts in the “Pulled Coupling Caps” thread where people have gone on to discuss other topics. That was an interesting morph by-the-way. It’s very similar to what happens at a party when the original leader of a conversation looses the interest of the other participants and everyone drifts away to discuss topics that they find more interesting and productive.

So Bob…DON’T BE A DUMBASS. You picked the name but it’s not required that you live up to it. If you want the original mojo back in your Bandmaster then review the threads and take advantage of all the advice from the experienced and knowledgeable people who have been trying to help you. That advice has been free to you but it did cost the contributors time that they could have spent on their own projects.

The End (of Tom’s rant … for now … maybe)

1010

A-Friggin-Men!

I, for one, am baffled. The thread title is "Please Help Me Trouble Shoot 64 Bandmaster", yet it appears that Bob is not willing to accept any help.

[dumbassbob]

Arrrrrrrg…WTF Bob! You have had at least two offers from members of this board to do hands on work to fix your amp. Now you want to send it off to another remote shop that will gut the whole board and start over? Now you want “clean with some balls” My dog can clean his balls but it doesn’t help my tone.

You don’t know what’s wrong with your amp and you don’t have the background to fix it. That is not your fault. You did good to ask questions here but then you didn’t take the advice offered. I feel safe to say that I’m not the only member frustrated by that. When someone asks you to do a specific test or answer a specific question it is to help them troubleshoot your amp. That’s part of the process of isolating the problem. What’s expected and what would be helpful is a clear and concise answer to the question. The story of how you have let yourself be mistreated has been sufficiently documented. We don’t need to hear any further rants about that. If you were to print out all the postings in the five different threads you started about this problem and read them in chronological order you will understand what I’m getting at. You can skip the recent posts in the “Pulled Coupling Caps” thread where people have gone on to discuss other topics. That was an interesting morph by-the-way. It’s very similar to what happens at a party when the original leader of a conversation looses the interest of the other participants and everyone drifts away to discuss topics that they find more interesting and productive.

So Bob…DON’T BE A DUMBASS. You picked the name but it’s not required that you live up to it. If you want the original mojo back in your Bandmaster then review the threads and take advantage of all the advice from the experienced and knowledgeable people who have been trying to help you. That advice has been free to you but it did cost the contributors time that they could have spent on their own projects.

The End (of Tom’s rant … for now … maybe)

1010

Your Right ...

[Leo_Gnardo]

My dog can clean his balls but it doesn’t help my tone.

Ah but does it help HIS tone? I'll bet he thinks it does. I could propose an experiment here but this is a family show so I won't.

------------------------------------------

OK back to the deflicted Bangmaster.

Never did get a measurement of input R. Bob, you can just plug a guitar cable in, & measure the R from sleeve to tip. You said those 1M measured low, this will tell us how low.

Bad bright switches? easy enough to measure whether they switch or not. Another ohm meter task.

What with all the in & out of those domino caps I wonder if they're still working at all. If they're open, that would sure as heck stop all treble. You could tack solder another cap say @ 0.001 uF around them (in parallel) and if treble picks up then you know where's the treble trouble.

Exploding bias filters. Harrumph! Won't be having that. I wonder if his majesty the royal Bloviator of Texas or his assistant put in caps with too low a voltage rating. Fender often did and got away with 25V caps in circuits that delivered over 60V but not for long. Gelard Weber could have made the same misteak that Saint Cesar did, and think they could get away with it because Leo Fender did. Not recommended. Make sure the bias cap is rated 75V - 100V and installed in the correct direction. Also a weak or underrated rectifier could wreck a cap. I use UF4007, if you don't have any ready to hand the more common 1N4007 works fine. Rated 1000V PIV - defnitely won't go bad in the bias circuit. If the bias department has been holding together recently, not much reason to worry, but DO check the voltage rating on the bias cap.

Say I just had another tiny brain wave. IF the bias pot/resistor lost its ground connection, that could cause the voltage on the bias supply to rise, and pop the cap. Also would clamp down the bias current in the output tubes and make everything sound like crap. Small, and awful. For a lark, let's measure the bias voltage, OK DAB?

That cap with the lifted leg, ask Tom's dog what that means but seriously it don't mean a thing if it's not connected. Except sloppy work. HOWEVER here's another potential trouble spot. If that cap - the one that's connected - is leaky or shorted, that would also explain lousy sound. Measure here too, Bob, voltage on each end of that 500 pF cap. Could be a clue. Would affect both channels at once.

Pots? Yes if they were changed but that doesn't explain why the sound deteriorated. You could measure 'em, make sure nothing's gone goofy there. They look original in the photos but - who knows.

You could send it here too. Won't be free, but it will be fair. And I'll report the results so we can all get some relief. Like Tom's dog... Puh-leeeze don't send it off to GW or any unknown entity. I know there's a lot of folks who are beyond the point of caring, but there's also some who would like to see this problem sorted out and know why it's been so goofy. This case helps take my mind off of even more annoying things - in the news - I'll leave that to yer imaginations.

[Enzo]

At some point it must occur to us that a new eyelet board stuffed with new parts could be wired in place of the old, and probably eliminate the issues in the process for a hell of a lot less money than has been and will be spent.

[The Dude]

Yes, but what about the mojo? (joking, of course)

[Tom Phillips]

At some point it must occur to us that a new eyelet board stuffed with new parts could be wired in place of the old, and probably eliminate the issues in the process for a hell of a lot less money than has been and will be spent.

A lot less money than has been spent for sure.
...will be? Maybe
...should be? I say no but that would require some hands on bench time. Without that I can't be sure that the problem is even on the main eyelet board.

[Enzo]

Actually I was just at the Mojo web site checking out boards.


Tom, you are right, but by god a new board would eliminate a whole lot of stuff.