Tag Archives: Mods

Rolf’s Sony ICF-SW35 mod removes the beep sound

Many thanks to SWLing Post contributor, Rolf Snijder, who shares the following modification for the Sony ICF-SW35. The mod is very simple: remove one capacitor.

Rolf shows the capacitor location on the following images:

Click to enlarge.

Click to enlarge.

Thanks, once again, for sharing your modifications, Rolf!

Rolf’s LED backlight mod for Sony ICF-SW35

Many thanks to SWLing Post contributor, Rolf Snijder, who writes:

This is a simple LED backlight modification for the Sony ICF-SW35.

Simply add a 120K resistor and a bright LED:

Overview of resistor placement. (Click to enlarge)

Detail of Pin 10 (Click to enlarge)

Detail of resistor. (Click to enlarge)

Detail of Pin 10 (Click to enlarge)

Detail of LED placement–replacement of capacitor is not necessary. (Click to enlarge)

When you push the backlight switch, the light stays on.

When radio is turned off, the light goes off–then push light switch and backlight will stay on for 15 seconds or so.

Thanks for sharing this simple mod, Rolf!

Rolf’s PL-680 modification allows external antenna on LW and MW

The Tecsun PL-680

Many thanks to SWLing Post contributor, Rolf Snijder, who writes:

I did a modification today on the Tecsun PL-680 [which allows for an] external antenna on LW and MW.

The internal ferriet is also working, but on my active loop, MW and LW is now working !

So far away stations I can now receive on this portable radio.
It is only a560 pF capacitor added!

Click to enlarge.

Click to enlarge.

It works on LW and MW now with this mod.

FM is less now I think, maybe I will put it on a switch so I can turn it off.
And now also the ferrite is still working, so I hope to find a solution for that.

Many thanks for sharing your modification and photos, Rolf! Check out Rolf’s other PL-680 mod by clicking here.

Tecsun PL-300 series modification: disabling soft mute

Many thanks to SWLing Post contributor, Troy Riedel, who shares the following tip. Troy writes:

While surfing the Net I found the following procedure that is said to “disable soft muting in Tecsun 300-series radios”.

I have a PL-390 and this has indeed seemed to work on it but I didn’t notice a difference with my PL-365.

Since I just found & tried this, I don’t know if this procedure must be repeated each time you use the radio? Maybe [Post readers] have heard of this before and/or have experience with it?

Here is the “reported” [supposed?] procedure that worked for the PL-390:

To disabling “Soft Mute” on Tecsun 300-series radios:

1. Select a shortwave frequency, preferably where there is no stations transmitting.
2. Tune down the frequency range with the dial, don’t tune up or it won’t work
3. Press the VF Scan button to let it automatically tune down
4. Tune down with the dial to stop the automatic scan. If the background noise is higher, then the “soft mute” / “dynamic squelch” has been disabled.

Thank you, Troy! I was unaware of this modification, but it seems easy enough to implement.

Post readers: Anyone have experience using this mod across the Tecsun 300-series receivers? Please comment!

Tecsun PL-680: Rolf touts enhanced performance using PL-660 mod

Many thanks to SWLing Post contributor, Rolf Snijder, who writes:

I have made the same modification to the Tecsun PL-680, that was done [by many on the] PL-660 earlier.

The PL-680 is now a great radio; I think now one of the best! I do not own a PL-660, so I cannot compare.

Photo detail

Overview of modification.

For disable soft mute you can see the 2 joints and you must scratch a path on the print near the switch. (same on a PL-660)

Closeup of joint #1 (click to enlarge)

Closeup of joint #2 (click to enlarge)

With the tone switch [on the left side panel of radio] you can turn the muting on and off. On FM I need to set it on for better results, but on LW MW and SW always off!

Frequency adjust is with the pot: adj1391 in the right corner. (for the 1 kHz off freq)

Click to enlarge.

Hope I can help someone with this on your great site.


Rolf Snijder

Many thanks for sharing this PL-680 mod, Rolf! This seems like a simple enough project and one that can be undone if you aren’t pleased with the results.

Post readers: Please comment if you’ve made this modification to your PL-680 or PL-660 or if you have other successful modifications to share!