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Mark,

Obviously this resistor is underrated in wattage. Something like 1 ow 2W would be better. If a resistor looks like this, it should be a higher wattage. I have seen this problem of a overstressed resistor go up in value or open causing the same problem you have/had. An easy way to get the power needed is to parallel or series resistors, when possible. Sometimes getting the precision resistor in the wattage needed cannot be done with one resistor. You can use an 82 ohm 1 or 2W resistor in parallel with a 4700 ohm. That will give you 80,5938.,. ohms. Well within the 1% tolerance. This is provided you use 1% resistors or measured ones. Your plug-in is worth getting right because it is a rare piece. It looks in excellent condition.

Mark

Finally, it's all done, over 100 Tek mechanical and electro-mechanical items all photographed, identified and posted up on the stuff season page. There are some interesting bits there, from the skinny BNC nuts needed on a few scopes to attach the vertical input connectors, current probe housings and switches, case feet and panel latches, power switch tie-rod couplers, curve tracer parts to reed relay coils. You can see it all here:



No, it's not in numerical order, that's just how it turned out, so you can just go "control-F, then type in the part number you want" in your browser, and it will find it.

A lot of work, and many items are free (how can I charge for a setscrew?), so I am not sure it was time productively spent, BUT if it clears out these items, then susan will be happier, so that works for me.

all the best,
walter (walter2 -at- sphere.bc.ca)
sphere research corp.

So I confirmed that this amplifier should work normally when in the local mode. I also confirmed that this mod would only work on a 7704A with MOD 515C.

Back to the problem... In general the unit had low gain and when you use the Position control it would simultaneously adjust the gain of the applied signal higher at both extreme ranges of the control.

Solution: R705, bias resistor for the signal splitter amp, was out of spec. Was supposed to be 80.6 ohms but measured about 119 ohms. It was slightly discolored, see my photos... /g/TekScopes/album?id=263432

All in all good entertainment I would say.

Hi,

I bought just the PS, and no scope with it, and yes I ran it on 230VAC, but in this 230VAC part of the world, it is usually the RIFA's in the net entrance that give problems.
I already removed these :-) and recapped the Power Supply.

However, I ran the PS not in a scope, but just with using a dummy load.

It's my experience these Power Supplies are quite robust, and don't give many problems in general.

In my effort to repair this PS, these are the parts that are definitely broken.
I ordered replacements and marked these in pink in this picture :-)

/g/TekScopes/photo/263466/3216014?p=Created,,,20,2,0,0

To be continued,

Leo

Problem with spamhaus is it would appear that it only takes one email to them saying a domain is a spam source and they block it without investigation. ?

D.

Groups IO sent me a message the other day complaining that my mailer was bouncing messages and they were suspending email until I unbounced it.

Turned out my mailer was bouncing their mail because they were on one of the spam blocklists. I sent a note to support and it seems to be cleared this morning. Did this happen to anyone else?

I don't use anything exotic, just the sbl from spamhaus.org

I think you need to first create a new album and upload the photos separately.
Then put a URL link to the photos or album in your message.

One important thing to remember is that CB channels below 24 are NEITHER contiguous nor numerically ordered. So to repurpose these switches, you might set up an LED matrix to show continuity per switch position.

I’ve seen a few switch tables for CBs but it was decades ago. I’m pretty sure but not positive that all 40-channel CBs used a switched digital PLL and VCO arrangement and not the “rock crusher” crystal mixer common with most 23-channel rigs.

FWIW the digitally controlled rigs used an octal +1 switch matrix on the VCO, but some had hex inputs. Some also had a ROM to block non-permitted frequencies. Defeating the ROM was non-trivial and required significant surgery.

If CBTRICKS.com is still online, you may be able to garner more info there. Especially if you are converting CBs to other bands, you want to buy their DVD set if it’s still available.
It’s much faster to search a DVD than to download from their website, especially since some misguided anti-CB dweebs continue to engage in DoS attacks against them, 30 years after the CB wars ended.

73
Jim N6OTQ

Sent from my quenched-gap spark transmitter.

To All - I did not post that link.? Dont know where that came from.? i have not posted anythin to this list for a few months.
73,
Bill WA2DVU

I had to install the position potentiometer - it is missing - and therefore it must be the "upper and lower sreen switch" removed.
No idea, how the removement works? No scew, nothing?
I need your help.
Thank you very much!
Regards
Manfred

I bet this scope was originally being used at 120V mains, and the protection was barely being able to cope with the fault. But once put on Euro 240V it definitively was too much for the PS.

It looks like this encoder is arranged in 4 decks. My approach would be to look for a unique pin on each deck which is switched to more than one other pin as the shaft is rotated. This should be easy with an ohmmeter. If successful, I would assume that that pin is a common and connect it, through a resistor, to a voltage supply. Then, I would connect an LED from each of the other pins to ground (with the correct polarity. of course). apply the voltage and observe the result as the shaft is rotated. If you're lucky, this will give you what you want for each deck.

You're right, trying to work it out with an Ohm-meter will take forever and possibly cause brain damage. So it sounds like a job for an Arduino (Nano). It can scan all the possible connections quickly and serial.print those that are connected. Then wait for you to click the switch and repeat the scan/print procedure.

Hi,

Interesting, that is definitely not going to work in a lot of places
outside the US. At least here, for example (Hungary, but I think true for
most of Europe) it is virtually impossible to pull money off an account
without explicit authorization. You can set up recurring variable amount
payments, like utilities bill, etc., but those can have limits and other
controls. There isn't any easy way for someone to just get money out of an
account without the approval of the owner. So I don't think this would be
the purpose for eBay.
As far as I know, with PayPal you only have to link an account if you are
selling and want to take the money out. At least I have never linked
anything to my PP account (other than a credit card (a virtual one, with
hard limits) and I was still able to buy and sell. I just used the amount
from the sale to buy other stuff (a lot of Tek stuff, to stay on topic),
never removed it from my PP account.

Szabolcs


Harvey White <madyn@...> ezt írta (id?pont: 2021. ápr. 28.,
Sze, 21:51):

Ed Breya <edbreya@...> added the album 40 position encoder switch: Accord PSS-23 switch

---

The following photos have been uploaded to the 40 position encoder switch album of the [email protected] group.

• encoder switch.jpg

By: Ed Breya <edbreya@...>

That link may not show properly. I have put a picture in the photos department, just in case.

Ed

I have a few old 40-position absolute encoder switches that probably came from some 40-channel CBs I junked out years ago. One of my projects is a special time mark/clock/risetime-check generator type thing to be built as a custom 7K plug-in. I need about 32 (5-bit) positions or more to control all the possible 1-2-5 sequence ranges from 1 nSec (1 GHz) to a few Sec (<1 Hz), so these 40 (5+-bit) spot ones would be great, and provide spare positions and allow absolute settings to be kept. The problem is to figure out how they're encoded. Regular binary or gray codes are often used for general purpose switches, but I don't know if these are standard - they may be specially coded for the original CB applications to synthesize the 40 channels, directly working the sub-parts, rather than telling a processor the setting. To make things worse, I can't find any data other than photos of various ones for sale. The switches look pretty nicely made, probably Japanese brand, called "Accord," and the base part seems to be "PSS-23." I found a picture of one linked below. Finally, to make matters worse yet, try searching something "accord" without the car showing up.



These apparently came in various position counts including 12 and 24, and of course 40, evidenced by the ones I have. The pin pattern seems to be fixed, with four layers of 5 pins per section, which would give up to 4-bits each, and it looks like the sections are paired, with the same kind flipped and attached. So, each pair set could be enough to provide at least 32 unique position codes, or lots more, depending on the coding arrangement. I have three pieces that look like the picture, with four rows of pins (two pairs), and two larger of the same style, with six rows of pins (three pairs). These bigger ones may have extra stuff for driving say, a two-digit LED 1-40 count readout.

Anyway, it would be very tedious to ohm out all the possible pin codes and even identifying which pin is which, so a data sheet of some sort would go a long way toward figuring it out, even if the coding is special. I'd appreciate if anyone has any info about, or knowledge of these switches. A long shot may be if there are any specific CB synthesizer designs that happen to use these switches - they must have been fairly common thirty or so years ago, for me to have salvaged out five pieces. The switches are held together with melted-head plastic pins, so can't be readily disassembled for inspection - it would be no big deal otherwise. It may become necessary to cut and goop as a last resort.

Yes, I know it would be simple enough to do an incremental up-down coder/counter deal, but I like the idea of having the absolute position coding - no remembering or resetting needed. That's what I was planning on before I discovered these little gems in the junk department. BTW the time and frequency will display on-screen only, so there's no need for 40 tiny knob marks and labels.

Ed

Hi Bill,
If you are going to post a suspicious link please be sure to say what it is for.
I can confirm (for Bill) that it is not suspicious after I checked it out.
It is a box of CRTs in the Portland area. At least one or two of them look like TV CRTs. The others are hard to tell. They appear to be old.
Dennis Tillman W7pF

Someone stated:

… "it's very important IMO that you use a *top* quality solder such as Kester even when unsoldering a joint. The Kester 2% silver loaded solder is hard to find and is now stupidly expensive but it's by far the best solder that I've ever used and I HOARD every bit of it that I can find and I use it very sparingly. I won't waste my time trying to use lead free solder. FOR ANYTHING!"


I agree, I have used many resin cored solders (60/40, 63/37, 2% Ag, 4% Ag, Alpha brand, Kester brand, No-name, etc.) over the past 50+ years, and in terms of rosin smell (some I just could not stand!) and ease of use, I prefer the 4% Ag from Kester.


Around 15 years +/- ago, I bought as much of the 4% silver solder as I could afford, the .015" diameter Kester 4% silver, leaded solder, mostly, in my opinion, the finest that I ever used. It truly makes beautiful joints, using any soldering iron (for over twenty years I used a “tip" oriented temperature controlled Weller WP-60-3) until I bought several of the stand alone Weller and JBC station/iron units. I happen to sell an occasional item on eBay, almost 20% of the time, its the: 12’, 25’, 50’, 100’, and 200’ lengths of that .015 diameter, 4% silver, leaded Kester Solder.


Sorry for the self-aggrandizing mention, but that solder is still available, and some 2% Ag also (until I get down to my last roll).



Steven ( stevenel57 on eBay )

Thank you Alastair for pointing out an extremely important point about all of these financial discussions whether it is with eBay, PayPal, Credit Cards, Banks (Federal or State), or Credit Unions: The laws governing these financial entities are totally dependent on the country they are operating in.

As near as I can tell most of this discussion is only relevant if you are in the United States and its territories. Other countries financial regulations, as well as their privacy laws, determine what can and cannot be done to you as an individual or as a company using the financial institutions in that country.

Dennis Tillman W7pF