TS-850S troubleshooting help

[KJ6MWZ]

Hi all, I have a TS-850S that used to work just fine (Receive only, no general ticket yet) but now doesn't seem to get anything. The speaker used to work as expected for HF listening, but now there doesn't seem to be any signal getting to the speaker from the RX circuit. I say this because upon each button press, the CW confirmation tone comes through the speaker loud and clear. I admit I don't have as deep a technical knowledge about this radio (or probably radios in general) as I should to start troubleshooting on my own; so any info or ideas or nudges in the right direction would be appreciated. I guess the major question would be should I keep it and fix it with the eventual goal being to use it, or should I sell it for parts to another HAM that could benefit from having some spare parts around, and get another HF radio when the time comes. I imagine that replacement parts for these are hard to impossible to source.

73,
Mark

[WB2WIK]

Did the antenna become damaged or disconnected? Did you accidentally turn down the RF GAIN control (outer ring knob around the volume control)? Accidentally switch to a filter that's not installed?

When you tune the main tuning knob, do you see the frequencies changing on the frequency display?

Edit: I see you're in Sandy Eggo. Pat WA6MHZ who is very knowledgeable about this stuff isn't too far from there, in the El Cajon area. Maybe if you're at wits end you can convince Pat to have a look at it.

Unless you have lightning damage or something weird, the rig should be fixable. Might be (likely is) an accidental adjustment.

[KJ6MWZ]

Hi thanks for the reply, in order of questions asked:

Antenna is still connected
Adjustment of the RF Gain yields no change
Adjustment of the volume control yields minimal change
Tried all filter combos with no change
Adjusted frequency with both knob and direct entry, seems to work as it should and display accordingly
No difference in headphone plug vs through speaker.

Update: So when I turned it on to check the knob frequency adjustment the radio seems to work just fine. So now I can call the problem intermittent. I have it tuned to the NIST time frequency at 2500 KHZ to troubleshoot. An hour and a half ago (and for a few weeks before that) I had no audio. Now it seems to be working alright. I swear if I ever come back to haunt anyone I will take the form of an intermittent electrical problem.

I beleive I have met Pat at the field day event that his club held. If this persists I will see what it will take to bribe him to come out here and have a look. I would still welcome any other input, I know there is a wealth of knowledge on these boards and am open to any ideas.

[WB2WIK]

The 850S, like many modern rigs (it's "sorta" modern) has lots of relays switching stuff. When you change bands, relays switch. When you transmit, other relays switch. A lot of panel adjustments cause relays to switch.

You may have just touched something that switched a relay and cleaned its contacts, so now it's better.

When solid state devices "blow" they don't recover and get better.

[VE7DQ]

It hasn't been mentioned, so... ensure that the squelch control is turned completely counterclockwise !

Yer welcome!
73
Tom

[KJ6MWZ]

Double checked and confirmed that the squelch adjustment was correct.

[KA5IPF]

Replace C187 on the IF unit and repair any damaged traces.

[N4EYZ]

Replace C187 on the IF unit and repair any damaged traces.

Sounds like the voice of experience!

[KJ6MWZ]

Is that something that someone with little board re-work experience can handle or should I take it somewhere?

[AF6LJ]

Is that something that someone with little board re-work experience can handle or should I take it somewhere?

Someone with experience.
If you don't have repair experience you would be better off letting someone else do it for you.