Nope:? 7D14 of which I have one, and 7D15 of which I have several.
Very different critters, 7D14 is about 500 Mhz, but not so versatile.? 7D15 is about 200 Mhz or so, and does period, events, and the like.
On the 7D14, I measured the input up to the tunnel diode, and that's fine.? I get the waveform that I'm supposed to get (I think) after the tunnel diode, which is the sine wave with glitches (I used a sine input).? What I can't see is the output from the large divide by 2, (that's where they get the 500 Mhz rating), and the rest of the counter chain doesn't toggle.
So I'm suspecting the large divide by 2.? Changing the bias on that chip does change readings, but they're not related to the input, but that says that the rest of the counter chain is OK.
The 7D15's I have some work, and I should likely go fix the others.
Thanks.
Harvey
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On 1/12/2022 8:57 PM, Mark Vincent wrote:
Harvey,
If you mean 7D15 and not 14, check the 151-0367-00 transistors for leakage between C and E. The leakage will check as a diode. Checking hfe will give way off results like 0 or way high like a darlington or value jumping around on meter so no need waste time testing them this way. I replaced these in my 15 and it did make it work right. I used KSP10BU as replacements. Those 0367 types are used in plugins, 46/7/85 and others. A 7B92A has a number of them in it and expect them to be leaky. That leakage will cause things to not work right.
Mark
