Heathkit SG-8 Signal Generator

[Notimetolooz]

About that 2420 counter, since it is capable of high accuracy there are a few things you should understand about frequency counters.
The oven crystal oscillator is very stable, however there is an adjustment, a calibration, that is critical so that the display is as accurate as it can be.
The oscillator is capable of staying on frequency within better than 1 ppm (one part per million) that is 0.0001 %, much better than any voltage, current or resistance meter measurement. You need that much accuracy if all 8 digits of the display will mean anything.
However if the crystal oscillation is only calibrated to an accuracy of, say, 0.1% then the display will be off that much. So the calibration needs to be checked from time to time against a frequency source of even more accuracy.
One way is by using super accurate frequency radio broadcasts from stations like WWV and WWVH. More modern methods use GPS managed frequency standards.

[vortalexfan]

Originally Posted by Notimetolooz

About that 2420 counter, since it is capable of high accuracy there are a few things you should understand about frequency counters.
The oven crystal oscillator is very stable, however there is an adjustment, a calibration, that is critical so that the display is as accurate as it can be.
The oscillator is capable of staying on frequency within better than 1 ppm (one part per million) that is 0.0001 %, much better than any voltage, current or resistance meter measurement. You need that much accuracy if all 8 digits of the display will mean anything.
However if the crystal oscillation is only calibrated to an accuracy of, say, 0.1% then the display will be off that much. So the calibration needs to be checked from time to time against a frequency source of even more accuracy.
One way is by using super accurate frequency radio broadcasts from stations like WWV and WWVH. More modern methods use GPS managed frequency standards.

So basically the atomic clock stations in Fort Collins, Colorado and Kekaha, Kauai, Hawaii?

[vortalexfan]

I got the selenium rectifier replaced with a 1N4007 Diode in the Heathkit signal generator.

Picture of the repair is shown below.

[N2IXK]

Originally Posted by vortalexfan

I got the selenium rectifier replaced with a 1N4007 Diode in the Heathkit signal generator.

Picture of the repair is shown below.

Looks to me like the diode is in backwards....

[vortalexfan]

Originally Posted by N2IXK

Looks to me like the diode is in backwards....

You were right it was in wrong, just shortly after I read your comment and I was trying to test it out on an old Zenith Transistor radio I have and I heard a "Pop" noise and I checked it out and sure enough the filter cap that was attached to the diode had vented, thankfully i had a 22 MFD 160 VDC electrolytic in my stash that I was able to replace the vented cap with and now its fine, although I found out that apparently my Zenith radio was way out of adjustment because the 455 kHz IF tone couldn't be heard until around 600 kHz on the radio dial rather than at the end of the dial.

[Notimetolooz]

Originally Posted by vortalexfan

, although I found out that apparently my Zenith radio was way out of adjustment because the 455 kHz IF tone couldn't be heard until around 600 kHz on the radio dial rather than at the end of the dial.

There is something else wrong. First of all 455KHz is out of range of the AM radio dial, it usually doesn't go below 540KHz.
The second thing is that the 455KHz from the generator probably is so strong that it will get through the front section of the radio circuit so you should hear it regardless of the dial setting.
You should probably not use a direct connection unless the alignment instructions indicate doing it that way. I would use a loop unless the radio isn't working at all. In that case you would be using a type of signal tracing.

[vortalexfan]

Originally Posted by Notimetolooz

There is something else wrong. First of all 455KHz is out of range of the AM radio dial, it usually doesn't go below 540KHz.
The second thing is that the 455KHz from the generator probably is so strong that it will get through the front section of the radio circuit so you should hear it regardless of the dial setting.
You should probably not use a direct connection unless the alignment instructions indicate doing it that way. I would use a loop unless the radio isn't working at all. In that case you would be using a type of signal tracing.

Well the radio only has a ferrite bar antenna and that's it inside it so I was trying to just do a loose coupling by just dangling the test probe next to the ferrite bar antenna to see if I could get a response out of the radio (like I said I I don't have the service manual for this radio because I don't want to pay $25 for it over at Sams and I don't know if they covered it at beitmans or riders because of it being a transistor radio and it was a little after those companies went out of business.)


Also I tried using it to realign my old Philco 116B using the alignment instructions given in Riders and it actually ended up making it worse, and the instructions in the riders called for the IF Alignment to be done by having the positive lead (red lead) of the signal generator hooked up to the grid cap of the 1st detector tube with the grid cap connector out of the circuit (removed from the tube) and then the ground lead connected to the ground connection on the chassis (antenna ground lead).

Which when I did that I was able to peak up the IF really nicely but then when I went to the alignment of the individual tuning bands thats when I had problems on some of the tuning bands I couldn't get the signal to come through, it was completely deaf it wouldn't make any noise but the tuning meter moved though.

The only bands I got response from were the AM Band, the Police Band and the Long Wave Band, the two Shortwave Bands I couldn't get any response from, and once I finished the alignment and I went to test the radio's responsiveness with an antenna, I couldn't get anything in, it was completely deaf.

Is there something I did wrong?

The Philco 116B Manual is posted below.

[Notimetolooz]

Originally Posted by vortalexfan

So basically the atomic clock stations in Fort Collins, Colorado and Kekaha, Kauai, Hawaii?

Right. Probably more than you really need. Just wanted to let you know how involved things get when you deal with things at high accuracy levels.
One way is to tune in WWV at 10MHz using a receiver with an S-meter and zero beating with the crystal oscillator output.
Anyway that would be something for another thread.

[vortalexfan]

Originally Posted by Notimetolooz

Right. Probably more than you really need. Just wanted to let you know how involved things get when you deal with things at high accuracy levels.
One way is to tune in WWV at 10MHz using a receiver with an S-meter and zero beating with the crystal oscillator output.
Anyway that would be something for another thread.

Couldn't I just tune it in on one of my old shortwave radios? Also what's an S-meter and wh as t do you mean by zero beating with the crystal oscillator output?