Thread
Compact Mac CRT compatibility
Your physics teacher's hypothesis makes no sense. He may be a good high school physics teacher, but he clearly knows next to nothing about the physics of CRTs, if he's talking about "imbalances" and "voltage fluctuations" as having any relation to CRT voltage ratings. In trying to make sense out of your tech's nonsense, he's made up nonsense of his own, unfortunately.
Once again, there is no incompatibility among the CRTs of compact Macs. None. Again, I've swapped many over two decades of working on Macs, from 128K models to the Classic II, and there are many on this site who have done the same. There is thus plenty of experimental support for the assertion of compatibility, and there is zero contrary data. That's as scientifically supported as it gets.
Once again, there is no incompatibility among the CRTs of compact Macs. None. Again, I've swapped many over two decades of working on Macs, from 128K models to the Classic II, and there are many on this site who have done the same. There is thus plenty of experimental support for the assertion of compatibility, and there is zero contrary data. That's as scientifically supported as it gets.
To echo what other brilliant posters have said, the deflection yoke is the holdup. To offer a unique perspective, a similar problem is bedeviling me with a Macintosh 128k, serial number F4410PMM0001. The symptoms ate slightly different and the cause is also slightly different, but it is in the same general category. The difference is I don't have a vintage TV repair-person in my neck of the woods (Chattanooga, TN 37412-2718) that can A) cross-over to work on vintage computers; B) repair a 128k specifically; and C) offer a warranty. You have such good fortune that you have someone who fits all three of those categories, and I am praising the Lord I believe in wholeheartedly that you at least can have what I am so desperately seeking.
Hope this helps and have a great day!
Hope this helps and have a great day!
hey I clicked on bunsens link... and this part here:
So anyone know where to get these tools? because i used a regular metal allen key wrench to adjust the tuning coil in my CC yoke and it cracked and fell apart, i need plastic i assume.
So i will have to find these tools, and get a new tuning slug.
Sorry for hijacking, just a heads up since this is a CRT thread.
Well, the link they provided is dead now.
So anyone know where to get these tools? because i used a regular metal allen key wrench to adjust the tuning coil in my CC yoke and it cracked and fell apart, i need plastic i assume.
So i will have to find these tools, and get a new tuning slug.
Sorry for hijacking, just a heads up since this is a CRT thread.
I do have this Radio Shack set, but right now it's in storage with some infrequently-used tools. When I had to adjust a compact CRT a few months ago, I used the following:
1. For the standard slotted dial, a small eyeglasses screwdriver works well. Width is a slight problem, but if you're patient it should be fine. Make sure you insulate your tool with electrical tape.
2. For the hex, which is a plastic tool in the RS kit, you're going to be hard-pressed to find anything that fits. However, a little creativity goes a long way. I took an old plastic-handle watercolor brush, used 120 grit sandpaper to shape it, and after a little playing around it was able to turn the control without a problem. Make sure you use a brush with a thin handle at the end--you need something far thinner than a standard pencil. I could see a heavily sanded/filed Bic pen cap working too.
I did try an allen wrench, but mine was the wrong size. I'd take Techknight's advice and not attempt one.
If you do want real TV tools, the best place to look would be one of those independent TV retailers specializing in service. They may have some for the DIYers among us. Hardware stores, namely the mom-and-pop ones with plenty of old stock, may also be a good source. (Not to get anyone's hopes up, but I once found Duracell brand Mac Plus/512K/128K clock batteries at one, so anything is possible).
1. For the standard slotted dial, a small eyeglasses screwdriver works well. Width is a slight problem, but if you're patient it should be fine. Make sure you insulate your tool with electrical tape.
2. For the hex, which is a plastic tool in the RS kit, you're going to be hard-pressed to find anything that fits. However, a little creativity goes a long way. I took an old plastic-handle watercolor brush, used 120 grit sandpaper to shape it, and after a little playing around it was able to turn the control without a problem. Make sure you use a brush with a thin handle at the end--you need something far thinner than a standard pencil. I could see a heavily sanded/filed Bic pen cap working too.
I did try an allen wrench, but mine was the wrong size. I'd take Techknight's advice and not attempt one.
If you do want real TV tools, the best place to look would be one of those independent TV retailers specializing in service. They may have some for the DIYers among us. Hardware stores, namely the mom-and-pop ones with plenty of old stock, may also be a good source. (Not to get anyone's hopes up, but I once found Duracell brand Mac Plus/512K/128K clock batteries at one, so anything is possible).
In regards to Quicksilvermacs comment, the TV tech only bothered to repair/inspect my 3 compact Macs because they all suffered (with the exception of one now) from well-known TV problems. An analog board in a compact Mac in principle is no different from an analog board in a TV (despite their physical features of course), and the same goes with how a CRT operates. Naturally, if these Macs were suffering from logic board problems, then perhaps this fellow would have advised me to go to someone more qualified with computers.
Furthermore (and let's face facts here) TV repair as a practice is unfortunately becoming a dying breed. Nobody wants to spend extra money repairing their equipment (unless they are able to complete the task themselves), and the computers being sold now are either not worth repairing (as they become obsolete within the year, or the warranty has expired), or are not user-servicable (like the current MacBook series).
Quicksilvermac, I would like to hear more about the problem you are experiencing with your 128k. If you want to PM me, feel free to do so.
Furthermore (and let's face facts here) TV repair as a practice is unfortunately becoming a dying breed. Nobody wants to spend extra money repairing their equipment (unless they are able to complete the task themselves), and the computers being sold now are either not worth repairing (as they become obsolete within the year, or the warranty has expired), or are not user-servicable (like the current MacBook series).
Quicksilvermac, I would like to hear more about the problem you are experiencing with your 128k. If you want to PM me, feel free to do so.
Disposable chopsticks can be whittled down into fine tools, too. If you do use metal tools, please make sure to tape up the metal well to prevent shocks.
Would any tape work? I am assuming you are referring to electrical tape.
For turning the ferrite cores inside inductors, one generally should use a nonconductive tool. This recommendation becomes a mandate for inductors used in horizontal deflection circuits. So, even if you find a hex wrench that fits, you will find that the mere insertion of the tool into the core will perturb the adjustment. In severe cases, you will kill the circuit.
As the pdf doc suggests, you can fashion a suitable tool from cheap chopsticks. Just whittle one down to slightly greater than the final diameter, and gently push it into the core. Cheap chopsticks will readily conform to the hexagonal shape, but retain enough strength to make the adjustment.
As the pdf doc suggests, you can fashion a suitable tool from cheap chopsticks. Just whittle one down to slightly greater than the final diameter, and gently push it into the core. Cheap chopsticks will readily conform to the hexagonal shape, but retain enough strength to make the adjustment.
After reflecting on your friends' theories a bit further, I think I've figured out what they were thinking. It seems that I've overlooked the possibility of a mismatch in relative humidity specs. If the Aquadag formulations are designed for different RH, then there can be a large fluctuation in flyback inertia, causing an electron pile-up in the 2nd-anode area. But this won't cause any damage to your Mac. True, it might cause electron "whiplash" Bremsstrahlung, but that is a consideration only in esoteric corners of E&M theory (I'm sure your physics teacher can expand on this if you are interested), and has no practical bearing on your repair challenges. So, again, feel completely free to swap crts (but not necessarily deflection yokes) from one compact Mac to any other.
but if you use a nice clean even coat of dag, as i do with vintage TVs, everything should be fine. ;-)
Just to clarify: does this mean that one should keep a CRT and its original yoke together if you are swapping anything?
It's best to keep the deflection yoke with its original analog board if one is unsure of compatibility. The only problem arises when transplanting between Classics and the compacts that preceded them. Within Classics or within the other compacts, the yoke can be kept on the crt and the pair transplanted as an ensemble.
But if one wants a simply-stated universal rule that doesn't require remembering any of the above, "it's safe to transplant just the crt from any compact mac to any other compact mac" is it. Following it avoids compatibilty problems completely, but can force you to separate a yoke from its crt unnecessarily (and obligate you to additional post-transplant adjustments that then become needed).
But if one wants a simply-stated universal rule that doesn't require remembering any of the above, "it's safe to transplant just the crt from any compact mac to any other compact mac" is it. Following it avoids compatibilty problems completely, but can force you to separate a yoke from its crt unnecessarily (and obligate you to additional post-transplant adjustments that then become needed).