Installing SL30 in place of SL40 - test operation

Obscure question, maybe. If I slide an sl30 into an sl40 tray and power it up, should at least the comm side come alive?

Mine does not. The sl30 nav side requires power and ground of its own on its own connector, but the comm side is pin for pin common with the sl40.

While I should probably build a bench harness, I'm trying not to....

Thanks in advance, Rick.

Ps: Law of unintended consequences: think about the potential for changes through when building your panel. What seems obviously serviceable as you mount and wire on the bench is NO FUN once it's in the panel. In my case, the tray will not slide out the front because the rear tray connector header screws are wider than the tray by a solid 1/8". Big sigh....

rjcthree said:

If I slide an sl30 into an sl40 tray and power it up, should at least the comm side come alive?

Click to expand...

As I recall, the answer is no.

But, a 40 will slide into a 30 tray and work. But it will not latch in with the cam.

Rick,

I just did this, so let's see if what I learned from Stein and Jeb can help…Stein can confirm or deny!

Some of this may depend on what components you're hooking up to, but here goes:

In my case, I had an SL-40 in a Garmin stack. It was Comm 1 connected to a GMA-340, and it was wired to take autoload freqs from a 396 GPS.

First thing I learned was that the rear connector bracket for the -30 is slightly longer (deeper) on the right side (the Nav side on the -30). That deeper section is where the Nav antenna connector fits into. The difference is slight, maybe 1/8", so your -30 might not be going in all the way during your test. I don't know if the cam will partially engage and give you a false impression the radio is in. I also don't know if the comm half of the -30 will come on with just the comm-side power and ground connected...I didn't try a fit or a power-up in the old tray.

The potential good news is that even if your tray won't come out, you may be able to remove and switch the rear connector brackets while installed, though that may require some extreme gymnastics. Might be worth the try, though I know it won't be easy!. Then again, if the oversize screws you are talking about are for that rear connector bracket, maybe you can pull them off, since you have to switch those brackets anyway. Then you can pull the tray and work on the bench (way mo betta!)

Next thing I learned, which may or may not impact your install, is that there is a slight wiring difference on the comm side (the 15 pin connector that both units have) when going from a -40 to a -30. The RS-232 Serial wires are on pins 3, 10 and 11 on the 15 pin connector for the -40. On the -30, they are on pins 3, 4, and 5 of the 37 pin connector (Nav side). I don't know if this impacts the power-up or not. In my case, I only had the RxD wire installed, to take freq data from the 396. I did not have TxD (nothing to transmit via Serial in the 40) or the Serial Ground. When I swapped to the -30, I re-used the existing 15 pin connector and its wires from the -40, and just had to extract pin 10 on that connector, then move it to the -30 37 pin connector, into pin 4. After that, it was just installing the remaining needed wires into the 37 pin connector, per the install manual.

I've powered up the new -30...the radio works and it does show Nav frequency info. I'm just now installing the antenna, so I don't have a functional Nav check yet. Soon!

Hope this helps!!

Cheers,
Bob

Thanks!

Thanks Mike & Bob. I got that I needed from both of you. Bob, I hadn't hooked up the gps - in my case a 496 - but since you made it sound so easy, and I have to do the harness work anyway, I'm going to try it.

Thanks again! Rick

rjcthree said:

Thanks Mike & Bob. I got that I needed from both of you. Bob, I hadn't hooked up the gps - in my case a 496 - but since you made it sound so easy, and I have to do the harness work anyway, I'm going to try it.

Thanks again! Rick

Click to expand...

Rick,

The 496 Blue wire is what goes to the SL30 or SL40 RxD pin for freqs. That is the 496 Serial out. In my case, it splits and goes to my SL30 and my Dynon D100 (Dynon pin 22 there, FWIW, in case you have one of those too).

Cheers,
Bob

Yes...

Bob, I've got a D180, so I'm there. I just didn't carry it over to the sl40 way back when. This may be more of an upgrade than I thought!

I have confirmed that the sl30 will only power up when supplied with power to both the 15 pin and 37 pin connectors. If supplied by only one or the other, nothing happens. No screen blink, zero indication. As I look at it, that means there's no reason to supply the two power inputs from anywhere but a common source. Garmin requires them the be separately fused, however.

Building on.....

Yep..both Bob and Mike both got it right (and I happen to know both have recently been through this).

To keep it simple and for future archive:

1) You can put a -40 into a -30 tray,
2) You can not put a -30 into a -40 tray.

The trays are physically different - see pic below. The upper tray is a -40 tray, the lower tray is a -30 tray. Of course if you're determined enough, I have seen hacks (and I do mean hacks) that folks have done to make either one work either way, but I'd just recommend just getting the correct tray and be done with it. Plus, you're likely selling or otherwise going to dispose of the radio you're removing, so having a tray for the removed radio will add a good amount of value over selling it "bare".

Cheers,
Stein

And to add to what Stein confirmed, for anyone still building, if there is even the slightest possibility that you may upgrade from an SL40 to an SL30 go ahead and wire up the Nav side of the 30 tray even if using the 40 in it. It can be done and will work well with the 40 installed. This is exactly what I did during my build. There is just one detail to pay attention to. That is, do not tighten down the Nav connector on the Nav side of the tray. Just tighten it enough to keep it secured on the back of the tray but not to the point where any of the pins will come into contact with any part of the back of the radio. Then when you need to install the 30 it is just a matter of tightening down that connector, slide in the 30 and turn it on. Worked great for me. Oh, and Mike, the cam on a 30 tray will engage in a 40 radio.