13-01-2015, 03:59 PM
Made life so much easier when chasing errant digital timing signals between chips but it came into it's own diagnosing recommended replacement parts for the video stage in the computer pictured were just not up to the job. A pair of ZTX313s went whuff and the recommendation was a pair of BC548s would do the job, which they didn't as the MHz rating was so low they just stuck their collective thumbs in their mouths and clammed up. A real pleasure tracing all the chroma signals etc. from chip to chip and how they interacted with the two transistors in the final mix stage to produce a composite signal. A pair of MPS2369 transistors restored full operation.
