42-380 alignment - Printable Version
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42-380 alignment - spiderdrummer24 - 03-25-2018
Ok I'm having so much trouble here. It's my first radio and alignment job. I have a Heathkit V-7 vtvm and a little cheap $40 signal generator I got off of ebay. The signal generator is not that great but it does put out a signal. I have the generator leads hooked up exactly where it says. The alignment instructions say to put the positive lead (which i believe is red) to ground and place ground to anywhere an AVC can be obtained. I've been looking for the output of the AM detector but can't seem to locate it. I've been putting the vtvm lead on pin 3 of the 7C6 tube. I can get a voltage there but it doesn't move when I turn the slugs. Please help!
RE: 42-380 alignment - morzh - 03-25-2018
Positive lead to GND??? News to me.
RE: 42-380 alignment - Radioroslyn - 03-25-2018
Hi Spider,
Does your V-7 work ok?? The test leads on measuring DC will be the ones marked com which is - and the one marked DC (with the function switch on DC+). You may want to go thru the manual and make sure that the calibration it good and all of the functions are working. I'm always suspect about ebay purchases not that there all bad but most of the time the seller has no clue as to what their selling or the condition.
http://www.jogis-roehrenbude.de/Roehren-Geschichtliches/Zubehoer/Heathkit-V7-A/V7a.pdf
Just serviced a V-6 about a month ago for the same reason, needed it to measure AVC voltages on my old HRO. As for the avc line you can find it at the junction of #41 and 42. Would use the 15V dc scale. Select DC- on your meter connect the common to the chassis and use the probe connected to the resistors.
GL
RE: 42-380 alignment - spiderdrummer24 - 03-25-2018
Meter is good but that may be my issue. I don't have the adaptor for DC. Only AC voltages. I have another multimeter. I'll try and get a reading on it
RE: 42-380 alignment - whirligig - 03-25-2018
(03-25-2018, 04:19 PM)spiderdrummer24 Wrote: Meter is good but that may be my issue. I don't have the adaptor for DC. Only AC voltages. I have another multimeter. I'll try and get a reading on it
On my Heathkit V7, I replaced the DC connector to a BNC which made easier to connect to probes and test leads. Lately I just use a DMM since the input impedance of even the cheap ones are 1 meg or better. However, analog meters are easier to spot the max deflection than a bunch of moving digits.
RE: 42-380 alignment - Radioroslyn - 03-25-2018
As you may know the DC probe has a 1meg resistor in it. Is not just a solid connection from meter to probe.
RE: 42-380 alignment - whirligig - 03-25-2018
Boy did I forget! Had to open one I made for the V7 a few years ago and there it is, a 1 meg resistor soldered to the tip.