Did I miss a memo or something??? (GE 3-5811B related)

[kopcicle]

Appreciate the information. Does it still yield results by swapping C42 and C43 without replacing for a 1969 final? I just dont have a way to retune if I do swap out for a 1969.

I really really need to learn to read a schematic and not be instantly confused...

No gain to be had by just swapping the capacitors if the transistors aren't replaced.

Let's look at it from C42 onward left to right. To over simplify and confuse with a bit of analogy, it's a Pi-L circuit from the driver to the final where L7 is the tuning element.

And if you don't like that analogy try this. It's 120p through and 220p to ground vs 220p through and 120p to ground (and retune). A capacitor will block DC and pass AC. In this case more through is more better.With the caveat that the circuit is no longer resonant . Lucky you, you have L7. I'm guessing you haven't fallen into the TA7205P rabbit hole yet. Along the way you'll run into a number of creatures. NFB, THD, Total dissipation and wattage out into a 2 ohm load. It really isn't that hard to understand a graph.



The problem is the difference in drive also sets resonance outside the tuning range of L7 in most cases. If you're one of the fortunate few you'll see both sides of the peak, not just one. Ive seen this bottoming or removing the tuning slug. What the circuit is trying to tell you is L7 needs to be trimmed or C44 needs to be experimented with. Altering R22 curiously is not something I remember doing.

Disclaimer I am not an electronic engineer but I did stay at a Holiday Inn Express once. I do have numerous professional licenses as well as an amateur license. However impressive these documents may be they are more to do with fixing others messes than creating my own. No items of cultural or historic significance go into the creation of this information. While not inherently dangerous, manipulation of magic pixie dust is not intended for human or animal consumption and ought not be sprayed on open flames. The author cannot be held responsible for supernatural manifestations arising from use of this information. Flying monkeys with hammers not included nor covered in any expressed or non expressed warranty.

 

[doffo]

No gain to be had by just swapping the capacitors if the transistors aren't replaced.

Let's look at it from C42 onward left to right. To over simplify and confuse with a bit of analogy, it's a Pi-L circuit from the driver to the final where L7 is the tuning element.

And if you don't like that analogy try this. It's 120p through and 220p to ground vs 220p through and 120p to ground (and retune). A capacitor will block DC and pass AC. In this case more through is more better.With the caveat that the circuit is no longer resonant . Lucky you, you have L7. I'm guessing you haven't fallen into the TA7205P rabbit hole yet. Along the way you'll run into a number of creatures. NFB, THD, Total dissipation and wattage out into a 2 ohm load. It really isn't that hard to understand a graph.

View attachment 76480

The problem is the difference in drive also sets resonance outside the tuning range of L7 in most cases. If you're one of the fortunate few you'll see both sides of the peak, not just one. Ive seen this bottoming or removing the tuning slug. What the circuit is trying to tell you is L7 needs to be trimmed or C44 needs to be experimented with. Altering R22 curiously is not something I remember doing.

Disclaimer I am not an electronic engineer but I did stay at a Holiday Inn Express once. I do have numerous professional licenses as well as an amateur license. However impressive these documents may be they are more to do with fixing others messes than creating my own. No items of cultural or historic significance go into the creation of this information. While not inherently dangerous, manipulation of magic pixie dust is not intended for human or animal consumption and ought not be sprayed on open flames. The author cannot be held responsible for supernatural manifestations arising from use of this information. Flying monkeys with hammers not included nor covered in any expressed or non expressed warranty.

That Disclaimer is great! lol. Too good.

It will take me a bit to digest and understand whats going on,but hoping it will settle in and I can understand. Thanks again for the explanation.

With these changes, do the rest the Cybernet boards suffer this? Like is there a specific Cybernet board that was great and needed little to no changes?

I do have this old Kraco SSB De Luxe 23 channel radio, and for what its worth it sounds fantastic without the help of a power mic.

 

[doffo]

I promise I will double check it.... but it will take a day or two!!!!!!!!
I am "promised to the Missus" for some tasks here at home..... and THIS is how i stay married for 52 years!!!!!!!!!!

I promise I'll check!!!

Yesterday I went ahead and recapped the whole radio. The two resistors in question seem to be ok. (Maybe not the 1k resistor as its at a 2.xxK value. I forgot exactly what it was.), but they were at least in their right spots.

As I suspected, it needs the help of that power mic. Looking at the watt meter and holding the stock mic 2 inches from your mouth and not talking too loud, it barely modulates. Hold the mic right up to your mouth and talk, it then is ok. (Luckily no distortion.)

67484 is the serial number on this one, and the date code is 4649.