Re: 465B repair - no display


Jeff Davis
 

Hi Mark,


I've been looking for the parts you mention (Q1416, F1419, R1412, etc.) but can't find them in my copies of the 465B Service Manual. I have both the before and after S/N B060000 versions. Can you indicate what Service Manual has the descriptors you're referring to?


Jeff / N0DY


________________________________
From: TekScopes@yahoogroups.com <TekScopes@yahoogroups.com> on behalf of mark.g0mgx@gmail.com [TekScopes] <TekScopes@yahoogroups.com>
Sent: Saturday, October 14, 2017 5:42 AM
To: TekScopes@yahoogroups.com
Subject: [TekScopes] Re: 465B repair - no display



I've had a bit more of a poke about and have found the following:

The waveform at TP1486 seems good and varies with the intensity control as expected.


The voltages at Q1416 seem out of bonk. The base voltage is 0.565 (should be -3.3) the emitter is at 0.427 (should be -4.5) and the collector is 4.98 (should be -0.6).


I am somewhat confused by L1419; I can find where the fuse holder for F1419 connects to the PCB in that part of the circuit, but I'm wondering if the inductor is physically located on the underside of the board? The component name L1419 is clearly marked on the PCB but the component next to it looks like Red Blue Brown Red - I dont see how that's 80uH.and I think is a 26.1K resistor (R1412).


Looking forward to some pointers


Thanks


Mark
G0MGX







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