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| Thread ID: 37964 | 2003-09-23 05:19:00 | Monitor | B.M. (505) | Press F1 |
| Post ID | Timestamp | Content | User | ||
| 177283 | 2003-09-26 03:23:00 | Hi B . M . If you have decided that your CRT is actually dying, there are three things you can do to eke out a little more life . One works better than the other two, and you have to be handy with a soldering iron for all of them! The CRT heater will almost certainly be supplied by a 1 or 2 turn winding on the HV output transformer . This winding may not be obvious and is likely to be integral with the transformer . Whichever way it is generated, there should be two moderately heavy wires going up to the CRT base from the main circuit board, and if convention hasn't changed too much they will go to pins 4 & 5 on the CRT base, but don't count on it, trace it out for yourself . Identify those wires and see if there is a resistor or choke in series with either of them . The first option is to increase the voltage supply to the CRT heater element by either shorting out any series choke or resistor . That will supply more energy to the heater thus boosting its emission for a brief but glorious period of time . Second otion is to disconnect the existing supply and wind your own loop around the ferrite transformer core if you can get to it . Start with two turns and see how it goes . If it is too bright and you get white lines across the crt face at high brightness levels you may have to add a resistor in series to cut the voltage down . Something from 0 . 22 to 0 . 47 ohms will do . Third and by far the best option is to get a 6 . 3/7 . 5/8 . 5 volt filament transformer and wire that in place of the original filament supply . You need to be knwledgeable and handy enough to find the 230 volt supply for the primary, and to hang somewhere safe inside the case, but this works a treat and the 50Hz ac seems to rejuvenate jaded cathodes by heating more broadly across their surface . If 6 . 3 volts isn't enough, 7 . 5 almost always does it ok . Jaycar sell a suitable tapped transformer for $20 as CAT MM-2002 . I have used the latter method successfully over the years on a range of TVs and monitors and got years more life in some cases . Cheers Billy 8-{) :) |
Billy T (70) | ||
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