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woolyhead

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  1. My tenor trombone is old but it plays. However, as the slide approaches its maximum length it starts to judder. It has to be moving but it doesn't make any difference whether I'm blowing or not. Why might it judder like this?
  2. If a parcel or a letter with no franking on the stamp arrives, you can get the stamp off without leaving the small oval shape behind by soaking the stamp in water then carefully unpeeling it, being especially careful with the small oval part and not letting it separate from the rest of the stamp. A penknife or a scalpel can be useful here. Stick it on the next letter you post using a clear adhesive. I'm not sure but reusing stamps like this may be illegal, although how anyone would prove it had been used before I don't know.
  3. See Reset HP Printer on this forum posts, page 2 by Waldo . Although this refers to the printer, not the cartridge, I did wonder whether my HP printer's refusal of a certain cartridge was because the printer needed resetting. There is also a method shown on page 1 for overcoming the printer's refusal of a cartridge. I also wondered whether that works on the cartridge chip's stored information. Does anyone know how this cartridge refusal or acceptance works? What chip(s) make the decision, the printer's chips and/or software or the cartridge chip? If so where do they get their information from? And how do they know when a cartridge is running out of ink? In my experience they are often wrong about that, especially if the cartridge hasn't been used for a while. So what is the system and how does it work?
  4. I'm told that cartridges have a chip inside. What information do these chips carry?
  5. Thanks Waldo. That has cleared up some of my questions. I didn't imagine the HP chip could be flexible and as thin as you say but I can see it could be. My printer's contacts form a pattern that almost fully occupies the allocated overall area, although there is a small gap around the edges. I mean there are no large spaces on it, apart from the distances between contact pins. The thin ribbon you talk about would therefore spread right across the allocated area and the actual chip on it would fit between the printer's contacts. These contacts are a bit wider than a pin head and rise up about 1.5 mm and the gap between them is about 2.5mm. I know that chips can be smaller than 1mm in diameter so a chip could go between contacts ok. What about the frame. How thick is it? If it goes around the space allocated for printer contacts it has both elbow room (x.y) and height (1.5 mm in z). The only thing is the electrical situation: A compatible's contact's press on the HP chip's contacts and at the same time these HP chip contacts press on the printer's contacts. So at least some of the pins will have contradictory voltages on them. Electrical circuits can't have that situation. One or both the sets of electrical information has to alter so as to become just one set of values. If the chip's output impedances are considerably smaller than that of the sources internally connected in the compatible and then taken out to a compatible's contacts, the HP chip will win, as it were. And this has to happen for the trick to work. Otherwise if they are roughly equal impedances the result at every pin could well be that the voltage on it is the average of the two. So since the trick does work it must be the former situation regarding output impedances. Good old HP, giving their chips low output impedances! It would also suggest that the trick could not be played by using another compatible's chip instead of an HP one. Maybe only HP chips can do this. You've certainly made me think. a lot about this. Thanks Waldo. 6 hours later ... I just realised something about this question of two different voltages at the same point on every one of the HP contact pins. If the compatible's contact with the HP chip doesn't go right through the chip tape but only into the chip then coming from this there need only be one voltage on the HP printer's contacts. In case anyone is reading this let me say that I realise there doesn't have to be an actual voltage coming from the compatible because that would occur if the compatible had a different input impedance from the HP chip at every point. That would generate a different voltage at these points if the HP printer injected a constant current into each of these points, a different voltage from those of the HP chip. The net result would be the same.
  6. About this transplanted chip: why doesn't it still record the fact that it's cartridge is empty and thus fail to work as required when transplanted into your printer? About the frames: I suppose they fill the space surrounding the printer's contacts right up to its 4 edges and thereby position the contacts of the compatible. In other words act like a jig? That deals with the x and y dimensions anyway. One more thing I don't understand Waldo. In what plane are the leads on the chip positioned relative to the chip's body and how thick is the chip's body? What I'm asking about here is the situation in the z direction ie how the compatible's contacts can reach down to the chip's contacts, past the chip's body. After all, the compatible's contacts group is flat and it was designed to press down on the printer's contacts with no space between it and the printer's contacts. You're saying there is enough space for the compatible to go in and for its contacts to still press down on the chip whose own contacts are pressing down on the printer's contacts, aren't you? The chip must have a very thin body to make this possible I would have thought. Please don't misunderstand me. I believe what you have told us but just can't quite imagine this aspect of it. Could you please explain a bit more. Last question: how many times can you use this chip?
  7. Thanks guys. All done as you said and all working.
  8. Yes it does a bit, Waldo. I've got a pretty clear picture of what you've said now. Presumably there is enough space for the compatible cartridge and the chip, both in the space allowed for just the compatible. And I suppose the chip gets its power via the cartridge contacts in the printer. Your idea is very good indeed. Thank you for posting it to us. As it happens the supplier of my colour cartridge replaced the no-go one and the replacement works ok. But I will eventually buy an original HP cartridge, use it and then extract its chip and try out your idea for myself. Why does the chip work, seeing as how it will have come from an empty cartridge by then. Why doesn't it still record the fact that it's cartridge is empty and thus fail to work as required when transplanted into your printer? In your case, did the chip come from an empty cartridge? Also, what do the plastic holders do? I suppose their dimensions must be fairly critical? Are they used to hold the chip at the right place on the printer's contacts and to stop it sliding down below those contacts? I suppose they fill the space surrounding the contacts and get the position of the contacts by filling this space, right up to its edges. In other words like a jig? How many times can you use this chip? Sorry to ask so many questions but unless I understand exactly what I'm going to do it might not work out for me.
  9. That sounds ingenious! Could you tell me where in my printer I would find these contacts. Are they the ones which a cartridge touches when installed? Should I place the HP chip face up or face down? Presumably face up otherwise how could I place the compatible cartridges over the HP chip and make contact on the right pins?. Would I have to solder the HP chip in place? Could you draw a sketch of what you do, please, to make it easier to understand. I would like to follow your idea when I understand it a bit more.
  10. I tried to return it to one particular supplier but what an embarrassment ... it wasn't one of theirs. But I still have two more delivery notes showing two other suppliers so I'll try them. I like your suggestion of using a continuous ink system. I'd never hear of this type before. Also I'll start studying Epson printers for the reason you suggest. Thank for your help.
  11. Hi Max. No. I hadn't tried cleaning the heads but when I followed your suggestion exactly the heads were not cleaned and the error light flashed throughout the attempt. The printer just refused to clean its heads. I think Zach has the answer ie the cartridge is not accepted because the printer is very fussy about who made it. Some lookalikes work, others don't.
  12. Where can I get a replacement for the installation disc for my HP C 5280 printer?
  13. No Zach, it's not a bad one because it worked for some time before it stopped. I've heard of that service Zach but I don't do much printing. Do you think that may be the trouble due to the long elapsed time between attempts to print. Also I was given this printer some years ago and it wasn't new even then. But when it works the printing quality is good. I was not given the installation disc however. Do you happen to know if I can get an installation disc and where from?
  14. No, they are lookalikes but in the past they have worked ok
  15. Thanks swarfendor 437. I'll give it a go right now...... Well that didn't work for me. I keep getting the message "Cartridge error. Refer to documentation." But thanks for trying to help me.
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