开云体育

My ft857d has just developed a problem in recieve mode, in the cw, cwr and dig positions. This problem exists with nothing attached to the set as well... the fault seems intermittent as well and comes and goes continuously. Initially when first switched on its ok till it warms up a bit. Removed the covers and give it a quick look over. The fault appears to be getting worse. I had a look thru the posts but could not find any relation to my fault. any body got any ideas would be appreciated.....thanks.

Am 02.01.2011 08:10, schrieb opalminer:

My ft857d has just developed a problem in recieve mode, in the cw, cwr and dig positions. This problem exists with nothing attached to the set as well... the fault seems intermittent as well and comes and goes continuously. Initially when first switched on its ok till it warms up a bit. Removed the covers and give it a quick look over. The fault appears to be getting worse. I had a look thru the posts but could not find any relation to my fault. any body got any ideas would be appreciated.....thanks.

You could pick the demodulated, unamplified audio signal at the back
side's packet/data jack to see if the distortion is already present
behind the demodulator circuit.

If the audio there is OK while distorted on the main speaker, check the
electrolytic caps in the audio amp with ice spray, if one of them is
faulty. You can see the related caps easily in the neighborhood of the
audio amp IC TDA2003.


73 de Bert, DD5XL


--

There have been some problems reported with the ceramic filters
used in the FT-857D, FT-897D and Kenwood TS-2000. The symptoms
don't exactly match yours, but it might be worth researching.

<>

That message is the start of a discussion of the subject on the
FT-897 group.

Here is another post by the same individual on this list.
<>

Mike kc9doa

I am wondering if this easy mod for the 897/TDA2003 applies to the 857? (reducing harshness of audio output by filtering? via the mod) The mod adds cap and resistor the the TDA2003 supposedly at the suggestion of the part schematic but looking at the data sheet I cannot sus it out myself. Mod -?
Orig site where I found the mod-?
73
KK6QMS