[Premium-Rx] Help! - WJ HF-1000A turns on and off by itself

[Fabrizio Magrone]

Hi OJ,

>Anyone have any experience with similar behavior? Any input would be greatly
>appreciated.

I read that you already solved this problem, but may be my experience can 
be of some help to somebody.

I had the same problem with my Kneisner+Doering KWZ30 DSP receiver: it 
began to reset randomly, initially after a couple of hours of use, 
suggesting a fault related to temperature.

The first thing I considered was the power supply. The KWZ30 requires an 
external 13.8V power supply, but contains a power regulating board that 
becomes really hot in a few minutes. Moving or tapping a couple of 
components and wires in this board caused an immediate reset of the 
receiver. A few solderings had gone loose. I resoldered the components; I 
also added a tiny internal cooling fan, just to keep temperature lower. 
Problem solved. Or so I thought.

After a few weeks, the receiver began to reset again and the problem became 
more and more frequent. The power regulating board was just fine. I 
disconnected and reconnected the boards, spraying a little bit of 
deoxidizer on the contacts, to no avail. Then, I noticed that sometimes 
(not always), moving the interconnecting flat cables caused a reset. The 
flat cables are terminated with crimping connectors. With a pair of 
flat-nose pliers I "crushed" the connectors, to crimp the flat cable better 
between the two shells of the connector: this solved the problem 
completely. With time and temperature, some little wire had developed a 
loose contact. Should the problem arise again, I'd change the crimping 
connectors with solder types.

Hope this helps!

Ciao

Fabrizio



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Fabrizio Magrone, Forli, Italy (JRC NRD-535, ICOM IC-R71, K+D KWZ30, 30m lw)