What is the best method for cleaning the gunk off PCBs before doing a cap kit?
Cap Kit Tools
- Thread starter Danimal219
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Danimal219
New member
what should I use contact cleaner,alcohol,or fingernail polish w/acetone on the contacts?
RetroHacker
Well-known member
I always use isopropyl alcohol. 91% is best, you can get it at the drug store. It cleans and removes the flux from the solder. It's also great for cleaning PCB edge connectors and lots of other things, and it evaporates cleanly.
-Ian
SuperSprint
Well-known member
For gold edge connectors, a Pink Pearl eraser works better than anything else.
Those Radio Shack solder suckers are junk. This one is way better http://www.mcmelectronics.com/product/21-4699
Matt
mecha
Well-known member
I use mine all the time. only time it sucks (well, not literally) is if the solder joint has a very large pin in it that the tip can't get around ... it creates a vacuum and it doesn't suck the solder. I wish I still had my soldapult for that (shit ass plastic threads broke off on it), kind of a pain in the ass having to run 2 irons for something that's like 1-3 solder joints to desolder. I had bad luck with the soldapult too, maybe I'm running the wrong kind of solder tip to get it in there while I'm heating it up, selections are limited for my orange Weller, but I nuked quite a few pads/traces last year. nothing in my newfound wisdom this year that I couldn't get around fixing though. lol
I always mention that you shouldn't pay attention to the wizards here that do cap kits all the time when they tell you cap kits only take 30 minutes. maybe on the old dinosaur monitors they run, but when you get into the newer stuff that's got around 32-34 caps to change out, it'll take awhile.
always make note of your cap polarities. if you want to make your job easier, draw out a cap map (picture of where all the cap locations are) because when you're in the heat of the moment, you'll find yourself scrambling trying to figure out where everything's at. this is also a good way for marking off which caps you have replaced.
I personally don't solder in the new caps right away, I just bend the legs in tight. this is like a fail-safe for the marking method to make sure you did in fact replace every cap. there have also been times in kits that I've bought where the ratings were slightly different, it'll have like a couple different ratings listed for one particular cap, and then you'll find that you need a specific rating for another cap elsewhere... can't think of a pure example off-hand, but what I'm saying is one cap will require a specific rating, and another will be slightly negligible. this is why I don't solder first... then you can just pop it back out.
THEN when everything's all set, you're sure the polarities are correct, and every cap has been replaced, then you start going hog wild with soldering the new caps in. I personally pull my caps tight, that way they can't flop around or break. others leave them loose and bend them at angles (the smaller ones) ... is that so they can breathe?
oh yeah, and take your time. it's not a race. the results can be permanent.
My biggest problem with the Radio Shack suckers is that they dont create enough suction. I dont even have to fully apply my Soldapullt sucker to the joint, I just keep it a hair away, melt the solder with my iron and press the button. I do this without removing the iron from the board. Makes for a really clean hole. I've done it this way for 20+ years and have gone through maybe 2 tips and 3 suckers.
Matt
Cap kits get much easier as you do more of them. I can do a K7000 in under 15 minutes, less then 10 if I dont have to take it out and put it back. Your right though, the newer monitors have tons of caps and they do take longer then the older ones.
Matt
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Danimal219
New member
Should I always pull monitor doing cap kit?
ArcRevival
Well-known member
A pair of Snap On flush cuts are well worth the $$$ .
Forget the wick, get the solder sucker Gamefixer linked.
Use good solder, like Kester brand.
Forget the wick, get the solder sucker Gamefixer linked.
Use good solder, like Kester brand.
RetroHacker
Well-known member
Depends on the monitor, and the cabinet it's mounted in. Some monitors, like the G07 and the 4900 are really easy to get the chassis out of while in the cabinet. Others, like the Sanyo 20EZ and the 4600, are a real pain to get apart while mounted.
It doesn't really matter - just do whatever seems to make the most sense in your case. I usually just pull the chassis when possible, so I don't have to go messing with removing the monitor from the cabinet.
-Ian
Its funny how you get what you pay for. in 1987 I bought about $3000.00 worth of Snap-On and Mac tools. TO THIS DAY I still have each and every one of those tools and they are in great shape.
I cant tell you how many Chinese screwdrivers I've busted throughout the years.
Matt
modessitt
Volunteer: Encyclopedia Submission Moderator
I always mention that you shouldn't pay attention to the wizards here that do cap kits all the time when they tell you cap kits only take 30 minutes. maybe on the old dinosaur monitors they run, but when you get into the newer stuff that's got around 32-34 caps to change out, it'll take awhile.
Wizards, huh? There's no reason why one cap can't be pulled and replaced in one minute or less. You only unsolder two points, pull the cap, check the value against the new cap, put the new cap in correctly, and resolder two points. So, 32-34 caps should take about 32-34 minutes. Hell, I did one monitor that had about 93 caps (32 just on the neckboard). Took about an hour-and-a-half.
Now, I watched one guy take forever to do a cap kit, and his way of doing it is what took so long. So here's some suggestions for making it easier:
1) Have good tools - a soldering iron that doesn't take forever to heat the solder, a solder sucker that actually gets the solder out on the first or second try, decent flush cutters, and good solder (not too thin or too thick).
2) Have good lighting. A desk lamp is very helpful even if you have good overhead lighting. It helps you see the polarity markings, even if there is a lot of grime on the board.
3) Make sure you have enough clear space to work in.
4) Pull all of the caps out and arrange them in order of value. Make sure they are all there. This will help you find the one you need faster.
One problem that I see causes a lot of inexperience people to take more time is their reliance on cap lists or cap maps. They have to look at a cap map to find a cap, then find the value in their pile of new caps, then go through the process of pulling, verifying, and replacing the cap, then crossing the cap off the list before starting over again. This takes way too much time. If you did step 4, then you know you have all the caps you need, and have them in an order that will help you find it faster. You can then count the caps you see on the chassis and neckboard to see if they match the number you have in your kit. Sometimes it won't, as there will be non-polarized caps not included in the kit, or the kit won't be for every cap (like the 20EZ kits).
If you want to save time on not marking off the list every time you change a cap, but want to make sure you aren't wasting time by pulling a cap that isn't on the list, take a sharpie and mark the top of every old cap on the list. Then set the list aside and just start replacing the caps. Don't worry about doing them in numerical order. Just pick a corner and start pulling caps, going around the chassis as you go. Once you pull a cap, check the value, grab one from your lineup that matches (you can check your list if the values are different than what you expect, but there is no need to mark it off) and replace it. Keep going until you're done. If you marked the caps ahead of time, you will have none left over that have marks, and no new caps left over to put in. Save the list, as sometimes you will have caps without a list, and it'll come in handy.
I'm sure I made it sound easier than it is (or harder), but after doing it that way a few times, you'll find it cuts down on your time pretty well....
I was kinda thinking the same thing.
I'll go one step further. I dont even bother to unsolder the original cap. If your soldering iron tip is dry it will soak up enough of the solder thats holding the caps in place to where you end up with clear holes after the cap is removed. Takes maybe a few seconds to remove the bad caps. The only time I use a soldering iron on a monitor chassis is when I need to remove a large part like the flyback.
Matt
jonathan1138
Active member
The reason why there is so much contention on these Radio Shack Desoldering pumps became clear to me recently. I lost my trusty one (you know, the blue one) and ran out and got another. Needed to remove some transistors from a fairly new board (Pinball - i am NEW to vids). Damn near ruined the board cause the thing wouldn't suck - the new de soldering tool had little to no suction. I had a similar experience years ago with a prior one from Radio Shack.
I think there is a quality control issue on these things. Now on to finding my old one.
QC is a problem all over the place and in a lot of different industries (see my sig). Even the really old RS suckers cant compare to the Soldapullt's.
Matt
LyonsArcade
Well-known member
I"m just gonna chime in here and start some trouble
The whole "don't discharge a vector monitor with a screwdriver" thing is a bunch of bullshit. It's an urban legend.
Think about it. What you're doing is removing a static charge from inside the tube. As the monitor sits, 40,000 volts or whatever you want to put the number at is pressing up against the diode, because it's connected to the anode.
So, when you discharge the tube, you short the 40,000 volts or however much it is, into the frame, through the screwdriver. Where does the diode come into this?
It doesn't. It has the 40k volts or whatever pressing up against it the entire time the monitor is on, off, whatever... and all you're doing is removing it. You're not going to blow a diode by removing voltage from it.
I don't know how all that got started, but tons of people have said it's b.s. and I believe them. Zap away! Ask Bob Roberts about it
The whole "don't discharge a vector monitor with a screwdriver" thing is a bunch of bullshit. It's an urban legend.
Think about it. What you're doing is removing a static charge from inside the tube. As the monitor sits, 40,000 volts or whatever you want to put the number at is pressing up against the diode, because it's connected to the anode.
So, when you discharge the tube, you short the 40,000 volts or however much it is, into the frame, through the screwdriver. Where does the diode come into this?
It doesn't. It has the 40k volts or whatever pressing up against it the entire time the monitor is on, off, whatever... and all you're doing is removing it. You're not going to blow a diode by removing voltage from it.
I don't know how all that got started, but tons of people have said it's b.s. and I believe them. Zap away! Ask Bob Roberts about it
I"m just gonna chime in here and start some trouble
The whole "don't discharge a vector monitor with a screwdriver" thing is a bunch of bullshit. It's an urban legend.
I don't know how all that got started, but tons of people have said it's b.s. and I believe them. Zap away! Ask Bob Roberts about it
I dont know where it got started either but I'm going to +1 this statement. I've been fixing coin-op arcade games since 1984. I NEVER did anything but discharge tubes with a piece of wire and a screwdriver and not once did the high voltage diode get damaged.
I dont even bother to discharge any of the new monitors. I just pull the cap off and hope I dont get nailed! LOL!
Matt
ArcRevival
Well-known member
While I totally agree with the idea that you can discharge a monitor by shorting it to the frame ( and used to do it that way) , if you really want to do it right, just get a HV probe and use that to discharge it. When you are done with your cap kit you can use it to test and set the HV. That is how I do it now.
