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Need parts lists for monitor recaps

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DistantStar001

Experienced Member
Joined
May 8, 2019
Messages
178
So I have three green phosper displays that need a recap. The first is an Amdek 300, the second is an Apple Monior ///, and the last is a Kaga KG-12NU. I also have an Apple Monitor II (the one with a tilt screen) that will fliker initilly, if left idle for an extended period, but stabolizes after a while.
Additionally, I have a Color/Composite Apple //c monitor that needs a recap as well. Console5 has a kit for the //e model, but I don't know if that translates to the //c.

For the most part, the screens work, but the image flickers on all but the Monitor II. Unfortunately, for the moment, is not the ideal display for games and some programs as its current tube was salvaged from an IBM 5151. So the phophor has a pretty high persistance.

In any case, if any one has the cpacitor lists for each of these monitors, it would be appreciated.
 
You do not need to recap a monitor ///! I have worked on dozens and have never seen one that had bad caps. Those monitors JUST WORK! And the amdek 300 is built like a tank.
If I had to guess you are recapping because you THINK that is what your supposed to do, but I assure you! Dont do it! Those monitors will work for years to come on those original caps. I have a couple dozen on my CRT racks! Your new caps will be inferior!
 
VERAULT said:
You do not need to recap a monitor ///! I have worked on dozens and have never seen one that had bad caps. Those monitors JUST WORK! And the amdek 300 is built like a tank.
If I had to guess you are recapping because you THINK that is what your supposed to do, but I assure you! Dont do it! Those monitors will work for years to come on those original caps. I have a couple dozen on my CRT racks! Your new caps will be inferior!
Click to expand...
While I agree that both monitors are well built and for the most part, reliable, the issue is that image is flickering on both. The Amdek even appears to cut out from time to time (really, the image just gets really dim). This has been a continuous and progressive issue for both monitors. If I'm not supposed to recap them, then how do I stabilize the image?
 
you are describing corrosion on the potentiometers. Use some deoxit on all the pots and turn them back and forth after you add it, you will feel it go from stiff to loose. Turn a couple dozen times and repeat on all of them and then post back. Obviously changing all the pots youll need to adjust the video correct after this.
Also a dirty Composite/rca jack. I use an art eraser from japan which is infused with sand, and I use it to clean various things. It works well on polishing the ground can on composite connectors. Use what you have, a small wire brush and a drop of deoxit works to break the corrosion.
 
An image that simply "cuts out" could also be a bad solder joint. Sometimes around a big connector pin, the solder where it connects to the PC board can develop a ring crack that is barely visible. I had that problem with my old Macintosh back in the day, the video pin for the analog video cable connector did that.
 
I have seen cracks and loose connections on the composite connectors too. The apple II board is notorious for the ground shield of the video connector coming loose.

Again I need to stress the Monitor /// is in my opinion the best built monitor apple ever made. I recovered a crt tube from one which was under water for years! the imploshion band was paper thin. But the TUBE WORKED LIKE A CHAMP and had an amazing image. They only need a cleaning. They are amazing. If it wasnt for the slow phosphor Id say they were perfect. The monitor II, well its riddled with issues.

The amdek 300 and 310 are one of my favorite monochrome monitors perious. Especially in amber. I have never had to recap one.. even ones which extreme use and burn-in.
 
I cleaned the pots on the Amdek and it appears to be back to its old self. I'm still going to hold off on calling it fixed yet... Maybe give it a few days before I declare victory. But for the moment, the picture is bright an sharp, so I'm very happy. The Monitor /// will have to wait until at least tomorrow, as I ran out of deoxit.

I will admit that I suspected the capacitors because of the symptomology of the Monitor II. Like I said, that thing started flickering as soon as I dragged it off the shelf, but soon stabilized. I don't use it very often (not enough room), so I figured that the capacitors had discharged and took a while to charge back up. It's working fine now, and was one of the most extensive repairs I've ever done on a CRT (cracked internal plastics, loose bits, missing screws, I even had to replace the tube). Basically, it was a parts machine I got from my local recycler.

I'm going to reevaluate the Kaga. I already know that the composite port is flaky. I had intended to just replace it. Unfortunately, the pots for it are in a really awkward place (mounted to the top-back case behind the handle). But maybe I'll get lucky and a good cleaning will fix it right up.

The Color/Composite //c is a bigger issue. That thing never worked quite right. If anything's visible, there's raster on the screen and the image dims and flickers randomly. It was never heavily used. The person I got it from bought it new along with the //c. They played with it for about a week, then stuck it in a closet for the next 14 years. It was given to me after that, and it works, but the image has always had issues.

Lastly, I agree, the Monitor /// is my favorite green phosphor CRT. I don't know why, but the color on it is the most pleasing to look at. The Amdek is a close second. The green is a bit harsher than the Monitor ///, but still nice. I especially like that it doesn't get that warm during extended use. I don't have much space where it is, so my disk drive's been sitting on top of it. A few hours on the Monitor II and it was getting kinda warm. The Amdek stays cool to the touch for hours.

Thanks so much for steering me in the right direction.
 
Monitor II's are a whole different animal with various board revisions and recapping them I will admit is NORMAL.

The II apple color composite monitors (color composite, IIC color composite, and IIe color composite) are very similar in design but not the same. I have fixed a few which isnt easy as there are no schematics. Just play it by ear and dont assume caps unless you see signs of leakage. Watch the 8 bit guys episode about the garbage ones he found at computer reset.

The monitor // other than being a bit bulky is just well made like a swiss watch. I have the white phosphor variant and the beige bezel variant. They are just as reliable as can be.



Thansk so much for taking my advice! shame to harm such a well built machine.. Keep us posted.
 
Edit to my last post I just found".....The monitor /// other than being a bit bulky is just well made like a swiss watch. " Not the //, that thing can be heavily problematic.
 
I wonder if they built it better because it was part of a $10,000 computer?
 
If you ever look inside it seems it may have been a television at one time. But its certainly better made than the Apple /// computer.
 
I have nine green monochrome CRT's including 3 Apple ///'s and all work fine and have not had any caps replaced. The one exception is the 9" Apple //c because of it's small size and compact design
it has run warm over the years which has domed out some caps even though it's ok. But when I do recap it I'm only doing the caps that look suspicious. I'm an admin in the Vintage CRT Troubleshooting and Repair
facebook group and every week there are one or two posts where they have recapped a working CRT and now it has a problem.

Larry G
 
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