Sencore VA-62A 15MHz kit, cd, etc.

[M3-SRT8]

Originally Posted by Notimetolooz

You will need a miniature three pole double throw toggle switch, like this one.
https://www.mouser.com/ProductDetail...JWoVn8JQ%3D%3D
You might find it cheaper elsewhere.

I just got in this switch, but it's a 3PDT Switch with 9 lugs on the back. Not 6 like shown in Zenith's tutorial. And it's arrayed differently.

I think it's the wrong switch.

[M3-SRT8]

Originally Posted by M3-SRT8

I just got in this switch, but it's a 3PDT Switch with 9 lugs on the back. Not 6 like shown in Zenith's tutorial. And it's arrayed differently.

I think it's the wrong switch.

Nope. Duh. I get it. Just don't use the center three lugs.

[Notimetolooz]

Well well well, I must of had one less coffee than I needed.
I made a mistake somewhere along the line, I don't know where I made the mistake that you need a 3PDT switch! I'm going to have to go back through my posts and make the correction. Zenith's switch diagram shows it to be a DPDT.
DPDT is what his text says.
Thanks for pointing this out. No one including myself noticed it.
The switch only needs to be a DPDT.

[M3-SRT8]

I did the chip swap, and that worked fine. Every function was preserved, and the MHz Programming goes waaay beyond the stock 35-50 megs.

Then I added the switch, and that seems to work ok, but when engaged up or down in makes a little electronic burp, ever so slight. Plus, the unit lost its 39.75, 41.25, and 47.25 MHz trap settings. They all come up reading too low in frequency.

Why? And, do I really need the switch?

[Notimetolooz]

If you read all of the posts Zenith made he mentions that sometimes the PLL (Phase Locked Loop) oscillator will not lock on the frequencies at the extreme limits and toggling the switch could jog it into operating. So the switch might jog other things unfortunately.
Even though the RF-IF switch is set to 30-50MHz (IF frequencies), the change in the EPROM program really uses the RF oscillator section, not the IF oscillator when you select a frequency outside the normal range.
As designed the RF oscillator selection powers up the RF output amplifier not the IF output amplifier. The IF amplifier puts out a signal that is 100 times larger than the RF amplifier. (The TV tuner has a gain of about 100.) So the RF amplifier output is too small for use injecting into the TV IF. On the other hand the IF amplifier output is so large it would overload the TV RF (antenna) input. The switch mod allows you to select whichever output amplifier (level range) you want.

[M3-SRT8]

The reason for the "low" trap settings is that they are not "low"at all. They are tied to the MHz setting I dialed up, in this case 22.75 which in turn spits out 16.75, 18.25, and 24.25 MHz on the three Trap settings of 39.75, 41.25, and 47.25 respectively.

But here's a big problem. My scope doesn't pick up or measure ANY of these new custom readings.

[Notimetolooz]

I don't know.
I wish the part I ordered would arrive so I could try my unit.
The guy supposedly sent another one after the first got lost.