Electronic equipment repair and service manual search discussion Forum Index -> Equipment Repairs

Post a reply
Username
Subject
Message body Emoticons View more Emoticons	Font colour: Default Dark Red Red Orange Brown Yellow Green Olive Cyan Blue Dark Blue Indigo Violet White Black  Font size: Tiny Small Normal Large Huge Close Tags [quote="GadgetUK"]Thanks for the pointers! I didn't need to swap the red and blue cathode feeds I did a visual inspection first and noticed the red feed resistor burnt out, although it still measured 560 ohm. Replace the feed resistor, still no joy. Quickly checked the associated transistor (pair, darlington?) the secondary transistor BF422 was open circuit across B->E or C->E (can't remember which). Swapped the B and R transistors around and I get the same display issue with Blue, so looks like it was:- 560 ohm resistor BF422 I suspect from what I have read that there may be some future problems related to the red cathode... I don't full understand CRTs, anyone know what actually happens to / with the cathode connections that causes this kind of problem? Just interested in the theory more than anything. I will post back once I have confirmed it's working but the red seems fine now it has a new resistor and transistor. One final thing, anyone know where I can get a BF422 (or equiv) in the UK? Going to have a look at Maplin and CPC... And, does anyone know of online equivelance guides for replacement transistors? When I was fully in the electronics arena we used to use guide books for finding equivements, there must be something online these days?[/quote]
Options HTML is OFF BBCode is ON Smilies are ON	Disable BBCode in this post Disable Smilies in this post

All times are GMT

Latest Service Manuals : Minolta Trouble EP4000 029 • Kenwood DPC-X527 • Samsung 15 Precaution • Philips Philips 217U • Western Digital WD RE4 II • cy130101 panasonic • irf830 Inchange Semiconductor • pbg4 17in apple • VAIO VGN-NS Sony • 990 GC SW2.6 Op E . Various • CF-1000 panasonic • irf9z24pbf International Rectifier • LC4.2E AA.part2 Philips • B53-0112-00 Kenwood • STUDIO 1555 - QUANTA FM8 FM8B Dell •