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Is BF423 Same as F423?

By on April 28, 2008

I have seen quite a few components where the manufacturers had removed the front part number making us some hard time to find out the exact part numbers. Recently i have just repaired an IBM CRT 15″ Monitor with the complain of flyback line across screen and there was no picture too. After spending some time, i managed to find the culprits, it was the C945 and the BF423 transistors shorted in the CRT board. Both transistors located at the Green color circuit. Since i do not have the exact part number, i began to check on the scrap board and found F423. I asked myself, could this component same as the BF423? I tried it out and the Monitor worked perfectly okay.

I have came across Monitor board where the normal signal diode part number was printed as”48″. Do you know that you could have been mistaken it was a 48 Volt zener diode? It is actually a 1n4148 signal diode and the manufacturer had removed the front few alphabets! I did not know about it until i saw the board printed as “D” and not “ZD”. In order to back up my claimed, i saw few other similar diode part numbers in other sections of the Monitor board. It can’t be so many 48 volt zener diodes in the Monitor circuit. I replaced the shorted 48 diode with 1n4148 and the Monitor power came back! In electronic troubleshooting we have to be sensitive to the surrounding especially the components so that we could solve the problem fast by our own decision.


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