The Wonderful Old TS820S
or Don’t you just love that dial mechanism?

I just thought I would write down some info on the 820S. We have a lot of experience with these, and unfortunately have made the decision not to work on them, except for a few isolated cases. Most people want us to restore a unit that they have never seen working, or last worked 10-20 years ago. We have had too many bad experiences with these to continue. But…

If you want to tackle one of these yourself, here is some data that might help. In no particular order…

Connector pins
There are literally hundreds of connector pins in this radio. These connectors have two problems. the wire can break where it is crimped on to the connector. It is very hard to remake that connection. The fix I most often see is the wire soldered directly to the board in question.

The other problem is corrosion. This sometimes works. Carefully remove every connector, carefully noting how it goes back, as there are often open, unused pins. Put a tiny drop of Corrosion X on each pin on the board. We sell this stuff and we use it, cause we think it’s the best. Carefully replug the connector. You will be surprised how many connectors there are. I have had an 820 come back to life from just doing this.

Voltage setup
Carefully check the regulated voltages, just like it says in the manual. These units are so old, that the two voltages, 9.0v and 3.6v are usually way off. I like to put some Corrosion X right on the little trimmers. These things get corroded too. For some reason people usually just go to troubleshooting and do not check out these supply voltages. That can be your whole problem. Especially for such things as low receiver sensitivity, etc.

Display
The biggest problem with the 820 is the display. There are two boards in the metal display box, and they are both double sided, with atrocious soldering (usually). I think these were done with early wave soldering, and sometimes there is almost no solder on the tops of the boards for the components that make connection there. Carefully resolder everything you can get to on the top of the boards. Try it, and if it doesn’t work yet, repeat. Even if you get it working, that might be temporary, and it might quit again. Resolder some more.

We’ve only had one 820 display that had an actual bad part in it. It’s practically always the soldering.

Clean and Lube
Ok, by now you, probably have the idea that we like this Corrosion X stuff. Just liberally but it on the moving part of every single pot, rotary switch, flip switch, variable capacitor wiper, that you can find in the radio. To get it into the bigger rotary switches is a bit of a pain, but you want to get it on the rotating contacts. There are times when just doing all this can bring the radio back to life.

The VFO plug
If I had $5 for every time I have been fooled by a missing VFO plug, and started trouble shooting, I could take us both out for a nice dinner. Make sure that plug is in and that pins 8 & 9 are shorted. If it aint in there, then, the radio is no workee…

Final Cage
Check the cathode and grid resistors. Just measure across them with a good meter. If you measure more than 5.5 ohm, or 105 ohms, respectively, replace them. Also, inspect the caps and RF choke right there next to the output tubes that are connected to the tall choke. If they look cracked replace them. They can be bad and look fine, so always keep them in mind for low power problems.

Clean the tubes carefully, don’t wipe off the writing on the tube. Take the fan out and lube it, liberally (a lot). Usually it’s been a long time. AND THEN, make sure the fan works when you turn it on. Sometimes they are just stuck and need a little help to get going. Remember, whenever the unit is on, HV of 850v is applied to the tube caps, and it’s dangerous.

We’ve seen very few problems with the ANT relay in the 820, but it is possible.

ALC problems
In these older radios, you often have to retune the mix coil section to get decent ALC. When you have to do this, you are reducing the signal level for normal receive. When you can’t get the ALC level up enough, with the drive control set (don’t turn it from center) adjust the mix coil slugs to see if you can get more. This is a compromise and it usually works out. Usually a setting between what’s optimum for receive and ALC will work out.

If you do this, you are not reducing the radio’s sensitivity as much as you might think. The signal to noise ratio is mostly determined by the first RF amplifier, before the mixer. Your gain goes down a little, but sensitivity will still be good.

6 Responses to TS820S Page

  1. Mark J Scango says:

    You’re an island I see while adrift in a sea of turmoil.

  2. Gerald Case says:

    I would love an AT-200or AT-230.

  3. George Fodor says:

    Jim, I came across your site while buying some parts on line such as manuals for my ts820 and ts830s it was a god send finding, you, I sent you a e-mail on the evening of 12/21/14, I’m looking forward to some business with you.

  4. Russell L. Baldwin says:

    Nice work, you are a scholar and a gentleman

  5. Don Robson says:

    good info I have one of these radios , great unit and this will help . My counter works but will not read the frequency when tuned lights up ok.

  6. Jack Nelson K5FSE says:

    I just discovered your website after ordering some items from eBay. I have an 820 and 830 w/accessories and am really going to enjoy going through your site in detail.

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