Category Archives: Radio Modifications

Tecsun PL-880 hidden feature/hack: 1 kHz bandwidth on shortwave

[Note: This procedure was updated and simplified by Guillermo on 22 December 2017]

Many thanks to SWLing Post contributor, Guillermo, who writes:

I own the PL-880 and just discovered a new feature : a 1.0 kHz bandwidth mode on shortwave (SW only not in MW).

The procedure to get it is as follows:

Turn on the radio and tune any frecuency on SW . There is no need to connect or disconnect an external antenna and turn on or off the radio during this procedure.

Be sure that on SW the 4 button feature(press 4 for about 2 seconds) is ON and 9 button feature(press 9 for about 2 seconds) indicates a value of 13 or more and not less than 10.

Then turn OFF 4 button feature and then ON again . Press BW button and see the 1.0khz new BW on the screen. Now you can use it permanently on SW and ALSO on MW , UNTIL you press BW button again .

Well, I hope you understand this description–if not please let me know, and tell me if it works on your unit, or it is just works on mine.

Thank you, Guillermo! I see where this is somewhat of a fragile adjustment in that a number of actions could change the bandwidth back to a previous setting, but nonetheless is quite a fascinating hack/hidden feature! Thank you and I’ll add this to our list of PL-880 hidden features.

Post readers: please comment if you can successfully enable the 1.0 kHz bandwidth on your unit. Please comment with your radio’s manufacture or purchase date if possible.

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

3 Replies

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

11 Replies

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

4 Replies

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.

Greetings,

Rolf Snijder
Netherlands

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!

How to fix the Grundig S350DL’s mechanical tuning drift problem

5 Replies

The S350DL may look like a digital radio, but it’s actually analog inside and tuning is prone to drift.

Many thanks to SWLing Post contributor, Ed, who noted my comments about the Grundig S350DL’s tuning drift yesterday, and shared the following fix found on Jeff McMahon’s Herculodge blog.

Ed writes:

The Grundig S350DL’s mechanical tuning drift problem is reportedly easily correctable with a screwdriver:

(Source: The Herculodge)

[…]The drift on AM was terrible! After 10 minutes, it is jumping all over the place – if you touch the radio, the sound mutes and the display goes nuts. I pack it up to take it back but then I decide to google the problem and find this:

http://groups.yahoo.com/group/Grundig-S350/message/4644

I do exactly what he says – I pull off the cover after unscrewing all of the screws (including the 2 in the battery compartment).

Only the speaker is attached to the front. I remove the three screws from the display and then tighten the two screws on the tuning wheels. They were barely loose – almost not noticeable – so I was not too optimistic. I carefully got it all back together (the plastic pieces that hold the fabric handle on only go back on one certain way and were sort of a pain!). I cross my fingers, plug it in, and wow – a brand new radio. The tuning is perfect. Zero drift on FM and AM. AM sounds excellent.[…]

I have an earlier Grundig S350 that I bought at a hamfest years ago which had an easily-fixed power problem. For $20 it makes a nice bathroom radio and it sounds great, especially on FM.

BTW, I found schematics for it on radiomuseum.org, which is a great resource for radio schematics.

Thanks for the tip, Ed! I think I’ll crack open my S350DL later today and give this a try!

Schematic for the PLL EDUTEC 4-Band Digital Radio Weltempfänger?

5 Replies

Many thanks to SWLing Post contributor, Cezar Vener, who writes with the following inquiry:

I would like to ask you if you can help me with a schematic diagram for an EDUTEC 4-Band digital radio (PLL EDUTEC 4-Band Digital Radio Weltempfänger). It is not broken, but I would like to modify it. Of course, I could spend some time and manually extract the schematic, but I would lose too much time.

While I know that “EDUTEC” is a registred trade mark for technical (“non-food”) products that was sold by “Eduscho Handelsgesellschaft” in Bremen and also I found that it is now owned by Tchibo, well – I would like to kindly ask you for help in this matter? (course, if you can).

It is an old product, probably made in the 90’s and until now, I didn’t find anything on the net about it. I opened it and I found that its core is TA8132AN, and the FM section is made around TA7358AP. The audio stage is built with C1212C, and there is one more integrated circuit there, TA8148S (no datasheet on the net, but I found that is a DC-DC converter for electric tuning – built-in stabilized supply output for biasing VHF tuner variable capacitor / sine wave oscillation).

BTW, I found it also in SONY CFS-W504L 🙂

The PLL chip is soldered with the unmarked side, so I don’t know what type it is.

[See photo at top of post.]

Here is a photo of the rear back stand:

Unfortunately, there is no other model or name written on the radio.

I see there “CENTRON LABORATORIES LTD”, that points to the company with the same name from Gujarat, India. Very interesting :))

In the hope of an answer from you, please allow me to thank you and to congratulate you for the very nice site that you maintain there!

Many thanks, Cezar! It’s readers like you who make this site such a great one!

Post Readers: I hope someone may be able to help Cezar. This radio looks familiar–perhaps I’ve seen it badged with a different company name? Please comment if you can help Cezar locate a schematic.

Tecsun PL-660 Hidden Feature: FM Calibration

10 Replies

Many thanks to SWLing Post contributor, Rick B, who writes:

I just thought I’d share with you a hidden function I discovered documented on the web for the Tecsun PL-660. It’s how to calibrate the FM band if you have a radio that is off frequency.

As my current PL-660 is accurate on FM, I haven’t had to try this myself. But perhaps it could save someone else from having to return/exchange a radio.

http://kaito.us/miscellaneous/qa/how-to-calibrate-the-pl660-on-the-fm-band.html

“Re-calibrating FM, radio needs to be on and set to FM band. Tune to the desired frequency/station you wish to listen to, press “SYNC” for about 3 seconds back light will flash. Tune up until the frequency/station sounds more clear press “1” to confirm re-calibration. If done correctly the correct frequency/station will be displayed on the display. Keep the battery in for all the time…”

Very cool! Thank you for sharing the tip, Rick!