Please Help Me Trouble Shoot 64 Bandmaster

[dumbassbob]

Bob,
This Bandmaster been through a lot of work & rework. Can you post photo gut shot photos of the amp so we can see the current condition and workmanship quality? This may also help to identify any mods we should know about.
Tom

Yes it has,All the blue caps where pulled out,then put back in....How do I put a picture on here?...I will have to get someone to do it for me with a digital camara...I really want to thank you guys for the help..I know I wasn't crazy.. When the new 220k resistors get here I am hoping it might be a fix...I was really hard to see that the 220k at the Vibrato channel had a broken lead right up inside the resistors

[Tom Phillips]

...How do I put a picture on here?...

When you are in the reply window follow the path"
Go Advanced \ Manage Attachments \ Add Files
Then browse to the photo file on your computer and click the upload button.
It seems like a long process but it is easy when you get used to it.

[Tom Phillips]

... Look where the 100k plate R are, one 220k comes out of the vee shape ,but goes into a turret between 12ax7 tube pins 1 and 6 on both normal and vibrato channels I would think some how one would go to point X and the other to point Y...crazy huh

Yes crazy. That seems like a description of someone's modification. I've seen lots of variations in original Fender factory work but don't recall anything like that in a Bandmaster preamp circuit of your vintage. Also...what's holding the turret? I'm guessing that you mean a terminal strip attached to the chassis. Anyway, this is a case where the photo will be worth 1000 words. A marked up schematic would be worth 10k words. Sorry but your narrative descriptions just don't convey the information we need. At the very least I can't clearly understand what you have there.

[dmartn149]

http://www.webphix.com/schematic%20h...ster_aa763.pdf

[dumbassbob]

When you are in the reply window follow the path"
Go Advanced \ Manage Attachments \ Add Files
Then browse to the photo file on your computer and click the upload button.
It seems like a long process but it is easy when you get used to it.

Thanks Hopfully my girlfriend can help me out

[dumbassbob]

http://www.webphix.com/schematic%20h...ster_aa763.pdf

Thats it.....Thanks

[dumbassbob]

It would be real good to have a layout sheet for your Bandmaster, as well as a schematic. The layout will point out what's supposed to be where, and also show you any "secret" wires strung under the circuit board. Can some kind person point out where DAB can pick up a layout sheet online?

You have some AB resistors on the way, bound to be better than highly drifted resistors you mention in your amp. BUT in recent years I've found many brand new AB's (maybe NOS) to also be drifted out-of-spec. What's a mother to do ? ? ? FWIW Mouser has another brand of half-watt CC's and they tend to be closer to spec, so consider that. They also have the Mallory 150 capacitors which look different now - no blue plastic moulding - but are supposed to be the same "formula" Fender used in their classic amps. I get the 630V rated ones and never a problem. Also if you can't find a layout online, just send me your address & I'll put one in the mail for you.

Feedback resistors - typically an 820 ohm and 100 ohm. You'll see a lead going to the circuit board from one of the output jacks hot lead - follow that and there's your 820. The 100 is at the other end of the 820. You won't read proper values on these because they're shunted by the resistance of the output transformer's secondary winding, near zero ohms. You can lift either end of the 100 ohm and measure their values accurately.

That 820 Is one I thought Was bad,It sure is hard to get to between the 2 caps,Everthing has been soldered and resoldered so many times I was worried can the leads under the board fall out,or can solder build up under and short anything out?I do not want to blindly start tugging on leads...like a dumbass

[dmartn149]

Thats it.....Thanks

Glad I could help a little. I read these forums every day, but I'm like the recent immigrant in class who tries to keep up, but barely understands the language.

[Leo_Gnardo]

That 820 Is one I thought Was bad,It sure is hard to get to between the 2 caps,Everthing has been soldered and resoldered so many times I was worried can the leads under the board fall out,or can solder build up under and short anything out?I do not want to blindly start tugging on leads...like a dumbass

Haven't seen any of the underboard leads fall out, but have seen some comically huge lumps of solder under the board. (Sometimes I'm the one who put 'em there...) You can clear eyelets with your iron & solder sucker, fine tune that clear eyelet with solder braid. May help to loosen the screws that hold the board down, pry it up a little, tip the amp over on its front then back & rap the board with a screwdriver handle to shake out any loose bits. While the board is pried up peek under there with a strong mini flashlight and small mirror & see whether there's anything that's suspicious.

You can lift one end of the 100 ohm resistor then no need to squeeze probes between the caps to measure the 820. One lead on the output jack hot, and the other at the 820/100 junction and that'll read the 820. Also measure the 100.

Shortcut: knowing the 820 shunts the 100, IOW is for measurement purposes in parallel with it, I just measure the 100 and if it reads about 90 then everything's OK. (100 & 820 parallel = 89) Close enough for rock n roll.

Big thanks dmartn149 for the AA schemo & layout! And sgelectric & Jazz P Bass for the AB - you never know - Fender was often making an undocumented change here & there. (Permanently in transition?) I'm going to peer at some 60-63 schemos & see if just possibly DAB's 220K are some artifact of a previous design. Wouldn't it be a hoot if the board in his amp was a white/brownie board?

[dumbassbob]

When you are in the reply window follow the path"
Go Advanced \ Manage Attachments \ Add Files
Then browse to the photo file on your computer and click the upload button.
It seems like a long process but it is easy when you get used to it.

Tried several times and pics willnot download. Will try again!

[dumbassbob]

Here are Bandmaster chassis pictures

[dumbassbob]

1st 3. six more to com

[The Dude]

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

[dumbassbob]

4th pic

[dumbassbob]

[ATTACH=CONFIG]24811[/ATTACH][ATTACH=CONFIG]24811[/ATTACH]

Hope this helps