Kenwood TS-520SE Low Receiver Sensitivity Question

[WA2SFT]

This question is for the Kenwood experts.

I have a TS-520SE that has low receiver sensitivity compared to my other rigs. The TS-520SE reads anywhere from 3dB to 6dB less in signal when compared with same antenna for example.

I was told that there is a plug-in MOSFET (Q1/Q2?) that may be the problem but I have not had the time to pursue this issue.

Not a big deal but was curious and thought I might throw this question out there.

73,
Greg

[WA6TKD]

There is a Yahoo group that is for Kenwood hybrid support and advice that might also be a help:

http://groups.yahoo.com/group/TS-520_820_530_830/

[K0SPN]

You should definitely check out that group; there are plenty of knowledgeable people there (maybe one day I'll be one of those).

What immediately springs to mind is that the coil pack needs alignment.
This is covered in section 6 of the manual, and it's pretty easy to do; all you need is a non-conductive tuning tool for the coils. Don't use a hex key/Allen wrench or you'll break the slugs.
If you can't find one locally, you can get one from Ken, K4EAA, for about $5 shipped.
http://www.k4eaa.com

[KA5IPF]

The first rule of radio repair; Alignment does not cure a problem, only makes it harder to find.

Judging from the question you are comparing the s-meter readings which is invalid. You need to compare very weak signals on 2 radios side by side. The ones that don't move the s-meter. Ideally you would have a signal generator with a calibrated output to verify correct operation.

[WB5WSV]

I would recommend you contact the TS-520 or "Kenwood Hybrids Group" over at Yahoo. I am a member and they were very helpful in my fixing a TS-820S that had an incredible number of problems, most there when I got the rig and a few induced by me in the repair process.

As for the TS-520SE, I have a TS-520 and recently found a problem with it. Sensitivity "suddenly" went way down. I finally discovered that the pushbutton that switches to WWV is dirty and did not quite switch back in the antenna circuit. I first tried that highly scientific process of rapping on the set, noting that the problem seemed to momentarily fix itself with each rap. I traced this to the WWV switch, and repeated actuations of it brought things back to normal, more or less. I need to get in there with some contact cleaner and LPS-1.

Good luck!

Robert
WB5WSV