10 November 2007

my tecsun dr-920 seems fried

My Tecsun DR-920 radio is misbehaving. I got this radio in July 2006 from an eBay seller based in China. Recently I determined that the alkaline batteries needed to be replaced. This particular radio has lived in my dining room most of the time, and was only turned on occasionally. When I put a fresh pair of alkaline AA batteries in and turned it on, the frequency was stuck at 5081 khz, despite turning the tuning knob and moving the band switch. My first thought was that the batteries were inserted backwards but that wasn't the case. I immediately took the batteries out and left the radio alone for a few minutes, and tried again, but the result was the same. This morning, after several days of leaving the radio alone without batteries, the result was still the same after reinserting batteries. I'm under the assumption that leaving batteries in the radio while it is in this condition will do more harm than good.

I've heard of a polarity reversing problem with batteries, but I thought that applied only to rechargeable batteries that had extremely low voltage.

So I need to find out if there is a way to reset this radio. Eton's product manual for the Grundig G1100 (which is the same radio) didn't mention any reset methods, and I can't find any such controls. I just sent an email to the eBay seller that sold me this particular radio.

I may need to disassemble this radio and look for anything abnormal. If battery corrosion were an issue, I'd expect to see it on the contacts within the battery compartment, but it looks normal inside there.

This seems like revenge for my previous refrigeration of this radio.


br-swl said...

Hi weatherall! I gave a DR920 to my parents as a gift, and they use the radio exactly as you: in the kitchen, eventually.

The radio has more than 1 year of use, and it still fine! For a small kitchen or bedside radio, it works well!

Dr920 is not PLL or DDS based, there is no memories or direct frequency entry... so, there isn't a microprocessor to reset :) It is simple a multi-band receiver with a frequency counter.

I think you receiver has some problem with the internal oscillator, perhaps near the band-selection switch :)

Good luck!



Hippocrates J. said...

Thanks to your posts, I can now ask if the IF freq in this TECSUN DR-920 is at 455kHz or not - Anyone? I don't have the schematic for it. If anyone can email me a hi-rez scan of it., I'll appreciate it, In any case, thanks. As for my experience withis reciever, I concur that it is a 'convenientce' receiver. It overloads easily in the presence of nearby AM stations. But that's typical of direct conversion receivers anyway. It's a very nice desighn and it would be great if mods can be to it. TimeLake