Help: Removing cap cans heavily soldered to chassis on Traynor YGM-3

[bbrownsbrick1]

Hello everyone,
I am "essentially" a new member. I signed up a while ago but went on a hiatus until I learned more about amplifier circuits so I wouldn't be subject to embarassing myself...

Anyways, I have a 72' Traynor YGM-3 that has the original filter caps. I have the task of replacing them with a 32/32uf for preamp and 50/50uf for PS. The only problem,

I cant get the originals out! The grounds are soldered heavily onto the chassis. I intend on removing them and using a marshall style clamp in its place. I know I can leave them in there and mount the filters to another space on the chassis but this is not desirable as there is already little room in there. I have used two cheap 80 watts soldering irons and nothing seems to get them out of there.

Any good method on doing this? I know this isnt a technical question but its bugging the heck outta me. Thanks!

[olddawg]

You will probably have to use a big old Weller gun type iron like everyone's dad had as a kid insted of a soldering station. If you have to, get some desoldering braid and remove the excess solder a bit at a time. If necessary remove or heat sink with clamps anything that might get damaged near it from heat. Grab it with a big pair of channel lock pliers and wiggle it.

[bbrownsbrick1]

You will probably have to use a big old Weller gun type iron like everyone's dad had as a kid insted of a soldering station. If you have to, get some desoldering braid and remove the excess solder a bit at a time. If necessary remove or heat sink with clamps anything that might get damaged near it from heat. Grab it with a big pair of channel lock pliers and wiggle it.

This is a dumb question, but what is heat sink with clamps?

[jrfrond]

Yeah, a nice 200W Weller Solder Gun, a little flux and a solder pump (e.g. Soldpullt) will make shorter work of those caps. Borrow this stuff if you have to. Really, there's no other way around this. Techs and shops who work on amps regularly are already so-equipped.

[bbrownsbrick1]

Ok, Damn...
Also, when soldering in there lets say you nip a bit of a cap with the iron, take a small chunk out of once of the corners. I may or may not have done that to the capacitor on the reset switch, does that make it ruined? no way of testing for capacitance here either...Id like to add a 3 prong at some point and bypass the ground/reset operation switch altoghether too...

When soldering heavy stuff, whats a good way of protecting the other wires/componants and suck, especially since I had my hands tied with two 80 watt soldering irons...

I have replaced coupling caps and the like with ease, done some mods, but this heavy duty high heat stuff is killing me...

[olddawg]

This is a dumb question, but what is heat sink with clamps?

A heat sink clamp can be anything from an alligator clip to something that looks loke the end of your car's set of jumper cables. They just keep heat from going where you don't want it to go and damaging sensitive stuff near where you are applying the heat. You can also fold aluminum foil to protect from knicking components in the area from an unsteady hand.

[Gtr_tech]

Wow....an 80w iron (with a large chisel tip) should do the job. I use a Weller W100p for chassis soldering and it works great.....almost *too* hot. A large tip is key here....it retains heat where a small tip will not.

http://www.action-electronics.com/grc/wew100pg.jpg

That guy right there. I'm not sure if they make that model anymore.

[Enzo]

My old Weller 100/140 watt gun will do it, but I do have a 200w one also.

I always liked old Traynor amps for working in because ther was always so much room inside you could work on the circuits, while you were sitting inside the amp with several friends. Wwith room left over for the TV set.

Seriously, there is not room under that chassis for four little caps? There may not be room for dual can-type caps, but those four cap values should be no larger than your thumb.

[Bruce / Mission Amps]

Most of the time a gun won't cut it. I don't care how many watts... I have 240watter. The tip does not really have enough mass to get the job done.
A big ass, black American Beauty with a 1/2oz tip will heat it up enough to loosen the tabs, (most of us full timers probably have at least a 150 watter-300 watter).

YouTube- American Beauty 300 Watt Soldering Iron Demonstration

... but another easy way to do this is with a 13 oz hammer and a sharp chisel with a flat on one side.. like a well made carpenter's 1/2" wide chisel.
Slide the sharp edge into the solder at the tab and whack away.
Sometimes it works better to but the bevel down and the flat up.
I've never had one not come off doing it like that.
Yes, you have to sharpen the chisel every now and then.
The solder and the tabs are softer then the chassis and you aren't going to use the old cap anyhow.

[bryans]

Typically I'll use a dremel tool with a cutoff wheel at an angle where the cap and chassis meet. Just a little more on the cap side. Takes all of 2 minutes, then just touch up with a file.

If you need the solder in the chassis removed you can just file it down with the dremel.

Obviously this renders the cap you are removing virtually useless.... but I personally would consider a 30-some year old electrolytic to be that already.

In the past I used a ratshack portable butane torch! Wire proximity always worried me though...

First post! I'm not too into the forum thing, but I've seen some really good posts on here.... figured I'd contribute - and hopefully learn from some people!

[Alex R]

They sell big 100W+ irons for doing stained glass lead work, they are very cheap and mine does the job of chassis soldering just great. I can solder down the stands of a tagstrip to a steel chassis quick, dirty and easy!

[bbrownsbrick1]

Thanks for all the advice...

Finally did it! It took a while. I used a combination of soldering (2 80 watters), dremelling, and prying. While I was at it I changed the NFB. I used a 32/32uf JJ for the preamp and a 50/50uf for the power. Hopefully this will work out as expected. Thanks!

[dai h.]

In the past I used a ratshack portable butane torch! Wire proximity always worried me though...

I have the big Weller "Portasol", and I bet the "torch mode" would work!



should probably cover any nearby wire insulation (alu foil or whatever--remember to remove when done) and take extra care since you're dealing with an open flame.

[WholeToneMusic]

Big Bertha

Every one should have a Big Bertha laying around the shop.
Bruce is right, the guns just don't have enough mass. I have tried a gun and the tip couldn't hold up to the heat. The weller 100 watt iron works good for solder joints on the chassis and is fast.

[bbrownsbrick1]

Ok, now I will post some pics to see if I got the wiring right...im worried I may have grounded too many things on the same lug, also forgot to take a pic of the wiring before I redid it...thanks again!