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Tagged: get rid of it, It is already a bad tube
- This topic has 35 replies, 2 voices, and was last updated 1 year, 9 months ago by
Ralph Spracklin.
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AuthorPosts
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April 19, 2023 at 4:32 pm #24717
Sterling Spurrell
Forum ParticipantBroken one
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April 19, 2023 at 4:41 pm #24720Ralph Spracklin
Forum ParticipantO, I thought you said you have the Schematic. You are also saying it only happens on certain settings. And yes that is how it is supposed to work on the ShortSwitch, because not all the elements in the tube are shorting out. Also on some tubes, Pentodes and other multi-function tubes, some of the elements are connect internally, such as the Cathode can be connected internaly with one or two of the grids. This would possibly register as a short. The same goes for the Cathode and the Filament on some tubes. Nothings straight forward as it sometimes seems it should be. But I think we are making progress.
Ralph-
This reply was modified 1 year, 10 months ago by
Ralph Spracklin.
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This reply was modified 1 year, 10 months ago by
Ralph Spracklin.
April 19, 2023 at 4:46 pm #24723Sterling Spurrell
Forum ParticipantWhen I said certain settings, I meant still with no tubes in tester
April 19, 2023 at 4:57 pm #24724Ralph Spracklin
Forum ParticipantOK Sterling, I see the problem, the broken wafer switch and the wafer he replaced are of different design. And the new wafer will not work. You need a wafer that is the same as the broken one. Compare the connections on both of them. Not certain what he was thinking. My own thought is, in order to correct this you need the proper wafer, and you will also need to find the schematic. Also to many loose wires. Two green, a gray, a black and a white one near the top of the newly installed wafer, just hanging loose??????
Ralph
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This reply was modified 1 year, 10 months ago by
Ralph Spracklin.
April 19, 2023 at 5:04 pm #24726Sterling Spurrell
Forum ParticipantHere is tester before it went to shop and after
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This reply was modified 1 year, 10 months ago by
Sterling Spurrell.
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April 19, 2023 at 5:05 pm #24728Sterling Spurrell
Forum ParticipantSwitch looks the same
April 19, 2023 at 5:23 pm #24729Ralph Spracklin
Forum ParticipantNo Stirling, they are completely different look at the tracks, the contacts slide on, on each of the wafers. Daylight and dark. Did he pull the complete Wafer switch assembly out of the tester, including the shaft. I can still see the shaft in the second pic you sent. I am concerned that you still may have greater problems than you think. I would imagine that somewhere on that assembly is where those other loose wires belong. I think he pulled so many wires off, without tagging, and totally lost his way. However until the problem is solved, forget the shorts test. You can do that with a multi-meter, across the variouspins on the tubes you want to test for shorts. Use aligator clips and leads from your meter, and tap the tubes and watch for the continuity, making and breaking on your meter.
Ralph
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This reply was modified 1 year, 10 months ago by
Ralph Spracklin.
April 20, 2023 at 12:47 am #24731Sterling Spurrell
Forum ParticipantHe only changed bottom wafer. Also Ralph i am assuming since i never got to use this tester at all, the problem i am having is it has the meter movement going up and bottoming out, is that what it will do to show a shorted tube?
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This reply was modified 1 year, 10 months ago by
Sterling Spurrell.
April 20, 2023 at 2:19 am #24735Sterling Spurrell
Forum ParticipantAnd here is schematic
April 20, 2023 at 2:21 am #24736Sterling Spurrell
Forum ParticipantSchematic
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April 20, 2023 at 7:38 am #24739Ralph Spracklin
Forum ParticipantMorning Stirling
I’m beginning to get as frustrated as you must be. Can you address the following points?
(1) Can you get a better scan of the schematic(It’s very fuzzy and hard to decipher)
(2) You never addressed all those loose hanging wires, in the first pic, which are not connect to anything. This does not seem right, surely they connect somewhere.
(3) Can you not, when looking at the pics closley, see the glaring difference, between the original wafer regarding, design/profile/contact layout, with the replacement wafer. Not certain why you do not see it!
(4) In the in one pic it shows an orange wire to the right of the two red and white wires, and in another pic the orange wire is missing???
(5) Also in regards to you question about the Meter movement being irratic. This is showing that the continuity is making and breaking. What ever the cause of that needs to be determined. And yes, a short in a tube can be either a solid short or an intermittant one. Is there a Short-Light on this unit??? At least, with the Meter movement flickering, that may be telling us that the Meter itself may be somewhat working, however that does not mean it will be capable of giving accurate readings.
(6) I am also surrprised that no one else, who may be followng this conversation, has offered any input here. There maybe someone aboard here, that has the same Tube Tester, who may know more about this unit, than either you or I. As for me I have a feeling that this Tech of yours may have rendered this unit un-repairable.??? It may be cheaper to find another Tube Tester with the functions you want. Even if you find someone who claims to be able to fix yours (no guarantee there), shipping the unit, to wherever, comes at high cost.\, and hourly labor and parts may not come easily. So unless we can somehow, by some fluke of fate, can find a solution. I don’t know??? But we can continue to work on it. As for me, I think the minimum we need is the correct wafer, and a much clearer Schematic. These units are no more complicated than some of the radios we work on. In some ways it is just a complicated Power Supply Unit, with its multitude of switches, which is designed to apply proper voltages, In order to mimic what is or maybe be considered, normal operating conditions for the said tube/tubes being tested.
RegardsRalph
April 20, 2023 at 8:22 am #24740Sterling Spurrell
Forum ParticipantHi Ralph, still can’t see any difference, the switch may be rotated in different positions in separate photos.vThe donar was a complete switch from another 12 22 for sure.
April 20, 2023 at 8:24 am #24741Sterling Spurrell
Forum ParticipantLoose wires is just Pic of donar switch.
April 20, 2023 at 2:11 pm #24742Ralph Spracklin
Forum ParticipantSterling. What was throwing me was the long 1/2 moon shaped contact strip was missing on the first pic you posted. I suppose it had fallen off. I did not realize that and thought the wafers were different! You say you never tried using the tester, and you were just going by what the repair Tech told you. Why did you not try it using the the Tube Tester with your Variac, using information given on pages 8 and 9 of the Manual. Maybe, just maybe there is no problem at all.
However you would need a tube to test that had a known short, in order to confirm if indeed it was working or not. Let me know if it still is or is not working after you have tested a tube with a known short. For the purpose of testing for shorts,you can always test any tube for shorts using a Continuity Tester.
To use this method, you check each pin against all other pins, checking for shorts/continuity. If when doing this test, if a short shows, you will already know the said tube is faulty. You must also remember that some tubes will have internal connections within the tube, with the other elements, which can seem like a shorted element. For instance sometimes, on some tubes the Cathode can be connected to one or two of the grids. Also I have seen some tubes where the Third Grid and the Plate are internally connected. This you should confirm, prior to testing with your meter. Always check your tube Data Manusl for any anomalys such as this. Also remember that the filament pins will also show as a short, using this method. Of course, in this case it is only telling you that the filament is working properly. On some tubes such as the 35W4, the filament will consist of three pins, so it is buyer beware! When using this method, use you meter with aligator clips on the pins. Tap each tube to see if the short is intermittant. This method is slow, but works well. However when using this method it is wise to do the test above, prior to testing the tube for other test tunctions on your tube tester. Of course, there could also be other problems with your Tube Tester, but let us know how it all works out.Ralph
April 20, 2023 at 3:18 pm #24743Sterling Spurrell
Forum ParticipantWill test a tube over the next few days when I find a shorted one.
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