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Compact Mac CRT compatibility
- Thread starter Concorde1993
- Start date
Interceptor2
Active member
hey Bunsen - that link says it all. So reach for that CRT!
tomlee59
Well-known member
Don't worry about interceptor2's comments about capacitances, glue and such; they are irrelevant for your compact Macs. The yoke (not "yolk") is gently fixed in place by a weak glue. If you need to remove the yoke, it's not hard to do so, and it's perfectly legitimate to remove the yoke. Interceptor2's advice applies to some color crts, such as the trinitron, where the yoke and crt are carefully matched at the factory, and should be replaced together as a unit. Such considerations do not apply to the monochrome compacts at all. Similarly, the capacitance issue he raises is of no concern; the capacitance is integral with the yoke, so you'll never have to worry about it.
Just to reset things to separate signal from the noise, your donor crt is fully compatible with your recipient Mac, electrically and mechanically. The yokes also happen to be fully compatible. You may freely transplant without worries.
As the classicmac2 doc says, just discharge the crts fully, make sure the power cord has been unplugged from the units, and take care not to snap off the vacuum seal nipple at the base of the crt. Again, if you simply work slowly and carefully, you will have no problem doing the operation yourself. Just read the instructions thoroughly beforehand, prepare a good clean workspace, and you'll be done inside of an hour.
Just to reset things to separate signal from the noise, your donor crt is fully compatible with your recipient Mac, electrically and mechanically. The yokes also happen to be fully compatible. You may freely transplant without worries.
As the classicmac2 doc says, just discharge the crts fully, make sure the power cord has been unplugged from the units, and take care not to snap off the vacuum seal nipple at the base of the crt. Again, if you simply work slowly and carefully, you will have no problem doing the operation yourself. Just read the instructions thoroughly beforehand, prepare a good clean workspace, and you'll be done inside of an hour.
Interceptor2
Active member
:lol: - your mistake, fundamental, do you actually know how the circuit works? It would seem not.Indeed I might choose to swap CRT yokes becuase that's my business, and colour CRTs are very diff from mono, but that was not being disussed here. But to the average guy wanting to do the job, it can bring complications.
yoke vs yolk - typo in the rush to type, must have been the egg sandwich I was eating, Gosh some ppl.
I'm not going to enter into a flame war, I can see you are impressed by my knowledge and feel threated, here we go geek wars "I know more than you"
) cue flames...
tomlee59
Well-known member
The issue is one of providing information to the OP so that he can get his Mac fixed. The information I gave is correct: There is no incompatibility between the Plus and SE CRTs and yokes at all. He can swap them freely without worries. That's the only information he needed. Your post muddied the waters with extraneous, irrelevant information and correction was therefore needed. Don't take offense at the correction. Our job here is to post helpful information to those who ask for it.I'm not going to enter into a flame war, I can see you are impressed by my knowledge and feel threated, here we go geek wars "I know more than you"
cue flames...
Paralel
Well-known member
I agree with tomlee. The main goal here is to help and inform. For someone who is unfamiliar with a topic the minimal amount of information needed to comprehend the basics of a given subject or make an informed decision is a sensible approach. If the person requests more detailed information it can be freely given in a follow-up post.
Concorde1993
Well-known member
Fellas, fellas,
The objective here is not to create an online war. Naturally, I deeply appreciate all of the replies that I received on this forum. It's good to know that there are still people out there who continue to appreciate these computers (despite their vulnerabilities).
In regards to my TV tech friend, at least he took the initiative to take a look at these machines (and service one which was in desperate need of repair), because let's face it- these computers are obsolete, and there are many people who would simply turn away at repairing these units, either because it is not "economically worth it," or because the knowledge base is not there. I know, since I have been turned away by others who simply ask: "Why do you still have this piece of....?" and I am sure many people on this forum site have faced this problem as well, hence why we have all taken the initiative to learn how to repair our vintage Macs (and effectively, too!).
It's great to finally have confirmed that these CRTs are indeed compatible. When I have time (and I mean ample time to actually do the job properly, as I have never completed such a task before), I will get this done. The SE is a very reliable computer, but like all electronics, parts ultimately require service.
The objective here is not to create an online war. Naturally, I deeply appreciate all of the replies that I received on this forum. It's good to know that there are still people out there who continue to appreciate these computers (despite their vulnerabilities).
In regards to my TV tech friend, at least he took the initiative to take a look at these machines (and service one which was in desperate need of repair), because let's face it- these computers are obsolete, and there are many people who would simply turn away at repairing these units, either because it is not "economically worth it," or because the knowledge base is not there. I know, since I have been turned away by others who simply ask: "Why do you still have this piece of....?" and I am sure many people on this forum site have faced this problem as well, hence why we have all taken the initiative to learn how to repair our vintage Macs (and effectively, too!).
It's great to finally have confirmed that these CRTs are indeed compatible. When I have time (and I mean ample time to actually do the job properly, as I have never completed such a task before), I will get this done. The SE is a very reliable computer, but like all electronics, parts ultimately require service.
Interceptor2
Active member
The main purpose of these message boards is to be helpful, there is a lot of ppl with useful knowledge. I was unimpressed by the previous remark, I design monitors professionally so for someone to dismiss my technical statement and replace it with a wrong one, well really. )
I could give full detailled analysis on EXACTLY how the deflection circuit works, with calcs etc. but it is such an detailled and in depth subject this message board is the wrong place for it.
The orginal question is best answered with Bunsen's link.
) I could give full detailled analysis on EXACTLY how the deflection circuit works, with calcs etc. but it is such an detailled and in depth subject this message board is the wrong place for it.
The orginal question is best answered with Bunsen's link.
Concorde1993
Well-known member
Hi Interceptor 2:
I would be most interested in reading over any detailed information you have on the deflection circuit. If you want to send a PM with a link to a PDF document, or so forth, that would be most appreciated.
I would be most interested in reading over any detailed information you have on the deflection circuit. If you want to send a PM with a link to a PDF document, or so forth, that would be most appreciated.
Concorde1993
Well-known member
Just to give an update-
I spoke to my physics teacher about the issues pertaining to the CRT compatibility. Although his knowledge on vintage Macs is limited (he was a Commodore guy in his youth, or so I have been told), he states that perhaps the voltage difference that the TV tech was referring to could perhaps be the result of fluctuation in the power supply, or flyback transformer, which is causing an inbalance of some sort. Either than that, he was surprised to hear that a voltage difference could even have existed between two identical CRTs.
I currently have the Plus for sale, as the logic board, and floppy drive are sure to be of some use to someone who wants to upgrade their 128/512, or repair their Plus. I just have not had the time to complete this task.
Let me know what you guys think about this theory.
I spoke to my physics teacher about the issues pertaining to the CRT compatibility. Although his knowledge on vintage Macs is limited (he was a Commodore guy in his youth, or so I have been told), he states that perhaps the voltage difference that the TV tech was referring to could perhaps be the result of fluctuation in the power supply, or flyback transformer, which is causing an inbalance of some sort. Either than that, he was surprised to hear that a voltage difference could even have existed between two identical CRTs.
I currently have the Plus for sale, as the logic board, and floppy drive are sure to be of some use to someone who wants to upgrade their 128/512, or repair their Plus. I just have not had the time to complete this task.
Let me know what you guys think about this theory.
tomlee59
Well-known member
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.
QuicksilverMac2001
Well-known member
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!
techknight
Well-known member
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.
Scott Baret
Well-known member
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).
Concorde1993
Well-known member
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.
Concorde1993
Well-known member
Would any tape work? I am assuming you are referring to electrical tape.
tomlee59
Well-known member
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.
tomlee59
Well-known member
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.
