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Post by antonio on May 16, 2022 16:10:59 GMT
I changed valves from EL34's to 6L6's, pressed the on button on the amp and smoke, oops. Switched off and thought I'd better have a look inside so removed the two 6L6's and the two 5693 pre amp tubes, couldn't see anything burnt inside so replaced the EL34's, only to find one of the 5693's central guide pin has broken off, but I now have no way of knowing which way to insert the tube since I don't know the pin numbers on the valve  The good news, I replaced the pre amp tubes with the original ones the amp was supplied with and partnered by the EL34's the amp is working again. Strangely enough the sale for the 6L6's was for 3 tubes so I do have a spare, should I try again with the spare and the one that worked? and how do I determine the pin numbers on the broken 5693? |
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Post by karma67 on May 16, 2022 16:20:15 GMT
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Post by antonio on May 16, 2022 16:31:31 GMT
It would be helpful if I still had that central guide pin in place  |
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Post by karma67 on May 16, 2022 16:34:43 GMT
It would be helpful if I still had that central guide pin in place  thats why i asked if there was any trace or marks left where it had been. |
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Post by antonio on May 16, 2022 16:39:53 GMT
Unfortunately not, it's broken right at the top and I cannot tell which way the guide pin should go, also there are no marking on the bottom of the valve.
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Post by antonio on May 16, 2022 16:43:46 GMT
That little cut out for the valve to fit in correctly is in the one o'clock position on my amp
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Post by antonio on May 17, 2022 5:09:52 GMT
Here's a photo of the problem  |
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Post by firebottle on May 17, 2022 6:45:50 GMT
On the valves I have come across with the same problem you can usually see where the spigot was from the break line.
It usually shows as a little hump in the otherwise circular break.
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Post by antonio on May 17, 2022 8:04:25 GMT
firebottle I think you may well be right Alan now I am looking at it in the daylight: If it did go in the wrong way would it destroy the amp and do you think a little super glue would work to stick it back in place 
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edward
Regular
Still prospecting?
Posts: 194
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Post by edward on May 17, 2022 8:26:27 GMT
The heater pins will have continuity. Find the datasheet for the 5693 and determine which pins are for the heater circuit - most likely pins 2 and 7. Use your MM to find that continuity. Pin 2 will be on the LHS (when looking at pins), the other pins will be sequential.
When checking the datasheet for the 5693 confirm that no other pins have continuity (likely not) and then check to ensure your 5693 has no shorts.
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Post by antonio on May 17, 2022 8:48:44 GMT
Should added, the break at the end had broken 'jagged' so was not easy to determine where it should be placed, but I think I can make out the spigot mark Thanks for your help everyone |
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Post by lurch on May 17, 2022 9:16:54 GMT
Before glueing put a permanent marker line of the body where pin goes, also do you this with future tubes so you'll always know where spigot goes.
I do this when th all 6S*7 valves as have had the centre pin snap in the past.
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Post by antonio on May 17, 2022 11:02:43 GMT
Thanks John, exactly what I had thought about doing, will do it on all my valves like you suggest |
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