Kenwood TS-830S No display, no rx
I turned on my Kenwood TS-830s this evening for the first time in several months. The display flickered for just a few seconds and went black. I connected the antenna and there's no reception.
In reading the "Survival Guide" by DL9AI (http://www.dxzone.com/cgi-bin/dir/jump2.cgi?ID=13985), I see references to fixes for vfo jumping or frequency drift, but nothing specifically for no display at all.
The S Meter still lights and I think the heaters are working. Any ideas on what might have happened and the appropriate fix?
Thanks so much and best regards!
If it isnt a PS problem (isnt there an internal fuse, I dont have the manual out) then its typical Kenwood connector virus. The tinned pins develop corrosion
Take all the connectors (one at a time) off and reseat a couple of times and then power up, use a small wire brush on the male ends if it will reach. Ive also glued 600 grit wet/dry paper to a thin flat stick to get in between the rows, especially in a TS-940. You may have more than one offending connector.
Id stay away from DeWrexIt unless you can apply an absolutely tiny drop to individual pins and then work the connector on and off a few times.
Thanks for the advice on deoxit, as well as the sandpaper idea. I'm thinking that if it as a PS issue, then the s meter light would not even come on. I will clean the connectors and see what hAppens. Thanks!
Connector pins have a very thin plating on them. Use of anything abrasive (which includes sandpaper) is sacrilege, since it will quickly remove the plating. Even some contact cleaners have abrasive components. DeoxIT does not, and will do no harm. Just removing/reinserting a connector will often 'wipe' through any oxidation. I'd try that first.
A 600 or finer paper will do no more harm than a burnishing tool on relay contacts. Just dont keep rubbing, a single pass is all you need. Its a simple known problem with older KW gear that the plating corrodes.
An abrasive contact cleaner is fine for power relay (or switch) contacts, where there is plenty of contact material to clean or burnish. However, on contacts such as these that have plating in the microinches region, I prefer to start with the least aggressive method of cleaning. In order, I would go with:
- removal & reinsertion of the connector
- non-abrasive contact cleaner
- abrasive method(s)
Kenwood rigs of this era are known for solder joints that go bad. The corrosion of the pin(s) is caused by flux that didn't get cooked-out during manufacture. After some time, the flux eats thru the plating, and you have an intermittent (or open) solder connection. The slight mechanical stress of removing/reinserting a connector often causes a marginal connection between a header & PCB to go bad.
Back to the OP's concern. The TS830 has a PLL that produces the Local Oscillator signals. There are five VCOs that are selected by the bandswitch. If the phase detector goes out of lock because the VCO for a particular band is out of adjustment, it produces a DC signal to blank the digital display. This 'BLK' signal also disables the output of the PLL, and you get a dead RX & TX for that band. Feeding the PLL are the carrier oscillator, VFO, and reference oscillator. If any of these signals aren't there, the PLL goes out of lock, and ALL bands are dead (and the display is blanked).
David, is just one band dead or all bands? If it's just one band, try tuning the VFO from one end of the band to the other, to see if it comes alive. If it does, the VCO for that band is out of adjustment or has a component that has drifted. Before you do any contact cleaning, get the service manual out and start probing the PLL board (phase detector DC error voltage). You can find the service manual as well as other useful information here. Ken K4EAA is also very knowledgeable with the TS-830. You'll find his website to be very helpful.
This happened to mine also. It was an intermittent 'function' switch.
If this fails, the tranceiver losses the VFO output and you'll get
this symptom. Try turning this switch back and forth a bunch of
times before digging into connectors. Also, if you have an external
VFO connected, remove it.
So in other words, it's a poor intermittent connection issue.
Originally Posted by KB5RFT
73 de Charles - KC8VWM
North American QRP CW Club #3159, SKCC# 5752
Originally Posted by KB5RFT
I left my 820s off for a week and had a similar problem I solved it by keeping the radio on for a few days.
Also I would check the VFO plug and make sure its making good contact. (I believe the 830 has a VFO jumpered plug.)