How do I remove the knobs from a Deluxe Memory Man?

segaface · Post by **segaface** » Sat Feb 23, 2008 9:42 am

I'm trying to replace the JRC4558D op-amps in my Deluxe Memory Man reissue with TL072s per this article.

For the life of me, I can't figure out how to remove the knobs so I can unscrew the pots from the chassis- it seems like they're epoxied to the pots' shafts. I don't see a set-screw to loosen to get them apart. Any ideas?

Andy

PeterSawatzky · Post by **PeterSawatzky** » Sat Feb 23, 2008 9:53 am

The knobs aren't glued on, they're just really tight. Try prying them off with a guitar pick.

AstroDan · Post by **AstroDan** » Sat Feb 23, 2008 10:49 am

...or get two flat-head screwdrivers and slowly pry (with some thin cardboard underneath to prevent scratching).

segaface · Post by **segaface** » Sat Feb 23, 2008 10:58 am

Aha, thanks.

Now I have another problem- the stupid op-amps aren't socketed!

Andy

inverseroom · Post by **inverseroom** » Sat Feb 23, 2008 2:26 pm

segaface, meet solder wick

segaface · Post by **segaface** » Sat Feb 23, 2008 2:49 pm

inverseroom wrote:segaface, meet solder wick

I knew I was going to have to learn how do that one of these days. Arrgh!

willowhaus · Post by **willowhaus** » Sat Feb 23, 2008 7:00 pm

Eh, it's not that bad. I recently got well acquainted with solder wick, and it was OK.

Might I also suggest a magnifying lamp? Made ALL the difference for me, working on PCBs.

Rodgre · Post by **Rodgre** » Sun Feb 24, 2008 7:07 am

A word of caution. Solderwick will be great in this situation, but be careful not to let the soldering iron sit there on the pads long enough to lift them off the pc board. Some people simple clip the leads of the op-amp on the component side (if they're trashing it) and desolder one leg at a time to clear out the holes.

I like to use a higher-wattage iron, but heat each pad up in quick succession, not staying too long on each pad. Meanwhile, I take a small flathead screwdriver and wedge it underneath the op-amp, prying it up as the solder gets heated up on the other side.

I use the higher wattage iron for this because it will heat up the pads faster so this process goes quicker, but I'm careful to not sit there all day with a 100 watt iron cooking the hell out of my circuit board. I have found that with a lower-wattage iron, you have to heat the pads up for a longer period of time, and that's where the pads start to get messy.

Once you've removed the IC, use a little solderwick to clean out the holes, put in a socket, and you're on your way.

Roger

bradb · Post by **bradb** » Fri Feb 29, 2008 11:44 pm

+1 on cutting out the original ICs, desoldering pin by pin and putting in sockets.

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How do I remove the knobs from a Deluxe Memory Man?

How do I remove the knobs from a Deluxe Memory Man?

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