MTX 801D Amplifier Cap Help

[willne1]

Re: MTX 801D Amplifier Cap Help

Thanks for all the help Toasty, I'm going to order the caps you recommended if everything works out o.k.during the desoldering process (wish me luck).

[Toasty]

Re: MTX 801D Amplifier Cap Help

You did check those clearances, yes?

[willne1]

Re: MTX 801D Amplifier Cap Help

Now that you mention it...the big caps in the background are 32mm tall so the 35mm caps might be too tall, any other ideas?

[Toasty]

Re: MTX 801D Amplifier Cap Help

Just check to see what your clearances are. I'm sure the big ones weren't smack up against the case... or were they? Jeeze, we're only talking 1/8" here. Measure it.

Does this board slide into a grove in the case/housing?

[willne1]

Re: MTX 801D Amplifier Cap Help

Well Toasty, I looked at it again today and the cover comes down to within 2mm from touching, 35mm would definitely be too tall.

[Toasty]

Re: MTX 801D Amplifier Cap Help

Bah! I'll bet they'd fit. A little work with the shoe horn.

Anyway, try this one: (22x30mm, 3300uF, 50v)

http://search.digikey.com/scripts/Dk...me=565-2665-ND

Less capacitance than the first replacement I suggested, but still more than what's there and slightly higher ripple filtering.

[willne1]

Re: MTX 801D Amplifier Cap Help

Once again Toasty...Thanks, it looks like that's the one.

[Toasty]

Re: MTX 801D Amplifier Cap Help

Any word? Is it fixed?

[willne1]

Re: MTX 801D Amplifier Cap Help

Sorry for taking so long to follow up Toasty. I didn't have any luck with the amp because I couldn't get the old caps off the board. Man they're really on there good.

[Toasty]

Re: MTX 801D Amplifier Cap Help

What wattage iron are you using?

I'd recommend something over 50 watts maybe 80 w or better. You have a HUGE heat sink with those copper traces and it does suck all the heat up quickly.

LMK

Toast

[willne1]

Re: MTX 801D Amplifier Cap Help

Hako 936-12 and I also have a Weller 7200 gun I think it's 75 watts. I didn't try the gun. I thought that might ruin the board.

[Toasty]

Re: MTX 801D Amplifier Cap Help

I don't think the Hakko is strong enough. The gun should do a good job, but you have to be quick! Don't overheat the board or you will damage and lift the foil.

Use the procedure from the main page on badcaps.net. Down the left hand side there are some How-To's. Use the " heat one leg and rock it to one side then do the other the same way" procedure. Make sure that you can feel the cap come loose before you rock it sideways. It means the solder top to bottom has liquefied.

In your picture of the board bottom, the cap leads with the little square around them are the most treacherous. You have to apply enough heat to get the solder loose on the top side of the board, but not so much as to cause the trace to lift. Those are the ones that are most likely to get ripped up if you don't use enough heat. Heat the lead, not the solder. A little flux or extra solder will get it going quickly.

Also, heat the board from the top with a hair dryer while you're desoldering the caps. It will give you a bit more time and take less heat to get them out. Sounds like a bit of juggling, but it can be done.

Good Luck!

Toast

[Toasty]

Re: MTX 801D Amplifier Cap Help

@willne1

Any luck or progress?