Soldering Tips, pulling Caps and (R) in Fender Board

[dumbassbob]

I thought I would try pulling some caps on my Bandmaster.Are there any tips or things to watch out for

[Tom Phillips]

I assume you are asking about the classic eyelet board.
It's best practice to suck out the old solder and replace with new.
Watch out for wires that are connected under the board. If one falls out or becomes intermittent you will be in for some interesting troubleshooting.
Regards,
Tom

[dumbassbob]

1964 bandmaster I thought I would try to change the .1uf output caps Bruce said that might be one problem I thought I could just "heat and pull".That all a tech in OC was doing to it

[Tom Phillips]

"Heat and pull" does work and as you mentioned it is what many techs do. However, replacing the solder is the premium and best way to go. It is the method I use to insure that I'm giving my customers the best result with the highest reliability. However heat and pull will most likely be just fine for your personal experimenting. If you do a lot of work, especially if you repeatedly remove and replace parts in the same eyelet, you may want to get a solder sucker. You don't need a multi hundred dollar machine just a mechanical plunger type tool.

[Chuck H]

Heat and pull "works". But it's a little clumbsy. Often there is enough bend around the eyelet in a component lead, plus intertwining with other leads on the eyelet, that you really need to get under the component lead and apply generous pressure to get it out. I NEVER just heat and pull if I intend to save pulled components in a useable form (but if I plan to throw out the pulled components I always just heat and pull). You can easily ruin the component being pulled. You'll also spend more time with the iron on the eyelet, causing more heat into adjacent components and causing insulation to shrink back on jumper wires. If you have a sucker, and you think you may want to reinstall the components your pulling, use it. You won't always get all the solder off the joint, but a dot of fresh melted solder seems to add slip and allows comonents to pull easier. If you find yourself spending what you think is too much time holding an eyelet in a melted state, you probably are. Stop, let it cool and try again.

[dumbassbob]

I NEVER PULLED OUT A CAP TO ME IT JUST LOOKS LIKE A POOL OF SOLDER,i THOUGHT i COULD GET AWAY PULLING THE .1UF COUPLING CAPS CAPS i DON'T WANT TO HURT THOSE bLUE cAPS IF THERE STILL OK

[Tom Phillips]

It helps to visualize how your board was originally built. Fender assembled the parts board with flying wires hanging off before the boards were screwed to the chassis. The leads were bent over on the back side and trimmed before they were soldered. Therefore, the first time a part is pulled is the hardest because you need to pull a little extra to force the lead to straighten out and release. The boards were soldered from the back side. That is why there is such a large mound of solder showing on the top in many cases. They actually used more solder than required to do the job. The later silverface amp boards were not built as well. I have seen some factory original work where the part leads were just laid on top of the eyelet and soldered. One of the rules of good soldering is that the parts are supposed to hold themselves in place before the solder is applied. Solder is not to be used as glue and after a certain amount is applied, more does not improve the integrity of the joint. However, replacement parts on eyelet boards that are mounted from the top without the leads bent over underneath are not problematic if the solder job is done well.

Also be aware that the leads for some parts are routed to a second eyelet under the board. Therefore, those parts will never let go when you remove the solder from the first eyelet. This applies mostly to resistors and the filter caps in the doghouse. The Fender layout drawings will show most of these cases. (Indicated by dashed lines)

… i DON'T WANT TO HURT THOSE bLUE cAPS IF THERE STILL OK

In my experience, the blue molded caps are very reliable and long lived. I hardly ever find a bad one. Not bad for 40 to 50 year old caps.

[Chuck H]

The later silverface amp boards were not built as well. I have seen some factory original work where the part leads were just laid on top of the eyelet and soldered.

I've only worked on a couple of SF amps. I've never seen this. But that's just shameful. I even feel a little guilty when I mod eyeley boards and just use an "insert for the eyelet" bend in the component lead instead of a proper "wrap". That some amps were factory stock with leads just laid on top of the eyelet is disturbing. I understand the motivation though, If you've ever had to stuff more than four component leads and a lead wire into a standard 1/8th mount hole eyelet you understand too. When building I always stuff and bend anyway though it takes more care and time.

[Tom Phillips]

...that's just shameful...

Yep. Attached are a couple of photos showing just some of the hall of shame workmanship I found in a 1974 Deluxe Reverb. To be fair the workmanship shown was not typical. Someone really screwed up to let this one out the door.

[Steve Conner]

That's ghetto! :O

I do the same if not worse in my experimental builds. Usually if I think I'll want to change the part later. My solution is not to post pictures of it.

I would be worried about disturbing a connection underneath the eyelet board, or making it go conductive from excessive soldering heat. If a part was bad, I'd snip the legs and attach the replacement to the stubs of the old one. If it wasn't bad, I'd leave it alone.

[Chuck H]

or making it go conductive from excessive soldering heat.

On threads here people have said with absolute conviction that repeated soldering and excessive heat DO NOT cause those black fiber boards to become conductive. According to these threads conductivity on black fiber boards is a matter of either moisture or surface contamination. Blow driers and cleaning ALWAYS solve the problem.

I've seen it on Fender and Traynor amps where the boards weren't moist, the wax was stripped off and the surface cleaned... And you could still read voltages right off the board. The black pigment in those boards is carbon. In fact all black pigment is carbon. If you apply heat and high voltage long enough resistive pathways form. I've seen the same phenomenon cause fires when carbon particulate builds up on fluorescent lamp "tombstones" (the nubbers at the ends that hold the lamps)

I guess the fact that the black fiber boards do become conductive such that the only solution is replacement is our little secret. I think the reason people don't want to believe it is because they don't want to replace a whole circuit board. Which amounts to rebuilding the whole friggin amp. Not to mention the devalue to collectibles. But it's just horse blinders and there are many marginalized amps out there with conductive boards that have been deemed fine.

[Tom Phillips]

... I do the same if not worse in my experimental builds...

Me too. Quick tack soldering and flying leads is the way to go when prototyping and experimenting. It’s amazing how well a rats nest of components can perform on the bench. At least to prove out a design. Low noise design is another story but even that can be quick and dirty if you have a good shield to encase the circuit. There was a flurry of bench photos posted when Jim Williams and Bob Pease died last year. They created some real messes but they never, of course, shipped them to a customer.

[dumbassbob]

Thanks for the advice and help...My biggest problem I sent my 1964 Bandmaster that had been stolen from me and his exwife got it back to me So I had it sent to Kendricks and he kept doing "things" to it and it would sound great ,for 2 or 3 hrs,and it would start to sound bad..then he would have it again for months and months I would get it back ,would great for 4-5 hrs go down "I may not know alot about fixing amps but I have a good ear,and know when some thing is not right" After another 8 months I get it back,sounds great this time it last for 3 weeks playing it 1-2 hrs a day...vol@5 tone@4,bass@3 then goes down..So now I take it to a local OC tech Futara..He has it 2 months then a day before Xmas calls me "amp sounds great" as soon as I heard it I was pissed He took the little mods kendricks did to the preamp OUT Never fixed what I asked him to do what was the Harsh sound on the GBE strings It lost all its sweet tone..and i'm out another $235. I bring it back to him the day after xmas I told him I think the Bias it Out He told me I was wrong,he puts it on a O-scope Bad cap...And with signal coil Pups it sounds like crap...He started to heat and pull on the caps added resistors to ground changed the tubes to 12ay7 everything Never could fix it told me to go away So Now I have put about $900. into a amp I bought from the Hollywood Bowl when I was a kid in 1970 when they remodaled the place and where getting rid of all this old back line amps that Everyone from the Beatles to Hendrix used This amp sounds fantastic when its working,I just am going broke trying to do it, sorry for my ramble

[Tom Phillips]

Bob,
I have read the other posts about this sad Bandmaster story. I didn't make the connection that this was the same amp until now. I have worked on amps in similar situations and sometimes it usually comes down to one or two basic problem that were not properly diagnosed and fixed during the early repair attempts. All the subsequent repair attempts and mods can then add new issues. Hopefully the root problem will be found some time soon. Skilled systematic troubleshooting is what is needed. Did you ever post photos of this amp?
Tom

[dumbassbob]

Bob,
I have read the other posts about this sad Bandmaster story. I didn't make the connection that this was the same amp until now. I have worked on amps in similar situations and sometimes it usually comes down to one or two basic problem that were not properly diagnosed and fixed during the early repair attempts. All the subsequent repair attempts and mods can then add new issues. Hopefully the root problem will be found some time soon. Skilled systematic troubleshooting is what is needed. Did you ever post photos of this amp?
Tom

I do not have a digital camara.What I need is a good tech who will listen to me,Like the OC guy he kept saying I was wrong and He was the great Know all tech...I was thinking of sending it back to Kendricks but that means byby to my amp for 8 months and all the money to ship I already gave him over $500. and 3 times to ship so to play my amp for 3 weeks it spent 1 1/2 yrs in Texas I know it is just some bad resistor or cap Kendricks did change all the Big filter caps and all the diode and added el menco 960pf cap infront of the 250pf caps and did some thing to the power tubes but the OC tech pulled and I dont know what it was..Also the OC tech pulled off the death cap,but Kendricks had put a 3 prog cord on already so I dont know if that had anything to do with the Bias cap failing,after OC tech said he checked it all out and it was good