Robyn T-123B question

[Ronin]

Just got a beautiful and excellent working Robyn T-123B to add to my collection. Definitely a 9.5 out of 10... and about as close to brand new out of the box as I'm probably ever going to see.

Anyway, Does anyone here know why the channel indicator on the T-123B was laid out in different colors? I have been active in CB since 1976 and never heard anyone mention that there was a reason behind the color scheme.

For those that are not familiar with the radio, or what I am referring to...Ch 1 thru Ch 8 have a RED background, Ch 9 is BLUE, Ch 10 thru Ch 15 is GREEN, Ch 16 thru Ch 22 is back to RED again, and Ch 23 is GREEN.

Anyone know of any other radios that have the same channel/color coordination?

[Sandbagger]

Oct 7, 2010 20:49:56 GMT -5 Ronin said:

Just got a beautiful and excellent working Robyn T-123B to add to my collection. Definitely a 9.5 out of 10... and about as close to brand new out of the box as I'm probably ever going to see.

Anyway, Does anyone here know why the channel indicator on the T-123B was laid out in different colors? I have been active in CB since 1976 and never heard anyone mention that there was a reason behind the color scheme.

For those that are not familiar with the radio, or what I am referring to...Ch 1 thru Ch 8 have a RED background, Ch 9 is BLUE, Ch 10 thru Ch 15 is GREEN, Ch 16 thru Ch 22 is back to RED again, and Ch 23 is GREEN.

Anyone know of any other radios that have the same channel/color coordination?

Interesting choice of colors. I would think channel 9 would be red like some JC Penney radios did. Anyway, the reason for the colors has to do with channel usage assignments. Back in the early days of CB, the only channels which could be used to communicate between stations not under the same license were channels 10 thru 15 and channel 23. The rest of the channels could only be used for intra-station (stations under the same license) calls. And of course, channel 9 was reserved for emergency calls only.

The choice of channels was further understood, when you also consider the interference from ISM devices which were centered between channels 13 and 14 and the class "C" transmissions that were frequently heard on channel 23. The FCC desired the band to be used primarily by units under the same license, and only between licensees when absolutely necessary. So they assigned the best channels for intrastation use.

Those channel usage designations pretty much disappeared in the mid 70's, when the band was overrun by hobby talkers, which were mostly interstation communications.

[Ronin]

Thanks Sandbagger!

I figured that there had to be a logical explanation. I do remember someone telling me about a "band plan" 30 some years ago during a discussion of why the CB handhelds mostly came with crystals for channel 14 or channel 11.

I too would have thought that the color indicator behind channel 9 would have been red as I have seen on a few radios. I wasn't sure how long channel 9 was designated for emergency use (I was involved with the local REACT for a few years in the late 70's). My intial thoughts on this color scheme was that maybe Ch 9 was some kind of calling channel before it was an emergency channel.

I am usually not home on Wednesday nights, but at some point I plan on trying to get on the CRR with the 'new' Robyn.

Thanks again!
Jim

[Sandbagger]

Oct 8, 2010 7:09:55 GMT -5 Ronin said:

Thanks Sandbagger!

I figured that there had to be a logical explanation. I do remember someone telling me about a "band plan" 30 some years ago during a discussion of why the CB handhelds mostly came with crystals for channel 14 or channel 11.

I too would have thought that the color indicator behind channel 9 would have been red as I have seen on a few radios. I wasn't sure how long channel 9 was designated for emergency use (I was involved with the local REACT for a few years in the late 70's). My intial thoughts on this color scheme was that maybe Ch 9 was some kind of calling channel before it was an emergency channel.

I am usually not home on Wednesday nights, but at some point I plan on trying to get on the CRR with the 'new' Robyn.

Thanks again!
Jim

We'd love to hear that Robyn. Hopefully it doesn't need much work to get it going. If it's all original, it's a pretty safe bet that the filter caps will need to be replaced, along with the "firecracker" .1 electrolytic caps.

Yea, the choice of walkie-talkie channels was not arbitrary. It's true that channel 14 was the most popular channel for 100 mW "kiddie" talkies. It's also no coincidence that channel 14 was the most likely channel to receive interference from ISM devices back then, so it's a channel that could afford to be "shared" with part 15 devices. Channel 11 was a popular channel for higher power walkie talkies. It was also a designated calling channel at one time.

[Ronin]

Actually, it didn't need a thing. I got it from Paul/OT-8412/2IR473, so I am pretty sure he had it on the CRR as some point. If you never saw it...it is very clean inside and out. It works very well...3 watt DK, Fwd peaks to 12w with the stock mic with nromal voice audio. Receiver is as sensitive as anything else in the shack and it is a nice quiet receive with very nice audio.

I already popped one of the .1mF 600v caps night before last. Just sitting here.. listening away to the locals...and POW! Lol! It was the 'Atlas' oil cap in the transmit audio section (inside top cover, right between the 12AX7 and the 6BQ6 near the range expand adjustment). A quick trip down the road to Barbey Electronics to grab the last cap of that value that they had in stock, and she is up and running again.

So, I am compiling a list of the tubes and caps and will sit down one day and replace all the caps. I think most of the tubes are good, but I'll keep a fresh set on hand. Anything else in these Panasonic chassis radios that you would replace right away? I saw an older post regarding some of the resistors can go bad. I might as well refurbish everything I can.....it made it at least 35+ years and still looks like it just came out of the box... I might as well try to keep it running another 35 years!

[Sandbagger]

Oct 8, 2010 17:33:19 GMT -5 Ronin said:

Actually, it didn't need a thing. I got it from Paul/OT-8412/2IR473, so I am pretty sure he had it on the CRR as some point. If you never saw it...it is very clean inside and out. It works very well...3 watt DK, Fwd peaks to 12w with the stock mic with nromal voice audio. Receiver is as sensitive as anything else in the shack and it is a nice quiet receive with very nice audio.

I already popped one of the .1mF 600v caps night before last. Just sitting here.. listening away to the locals...and POW! Lol! It was the 'Atlas' oil cap in the transmit audio section (inside top cover, right between the 12AX7 and the 6BQ6 near the range expand adjustment). A quick trip down the road to Barbey Electronics to grab the last cap of that value that they had in stock, and she is up and running again.

So, I am compiling a list of the tubes and caps and will sit down one day and replace all the caps. I think most of the tubes are good, but I'll keep a fresh set on hand. Anything else in these Panasonic chassis radios that you would replace right away? I saw an older post regarding some of the resistors can go bad. I might as well refurbish everything I can.....it made it at least 35+ years and still looks like it just came out of the box... I might as well try to keep it running another 35 years!

Actually, if that radio has low hours on it, the resistors should not have changed value all that much. The Panasonic chassis radios are not as tough on resistors as say, a Tram D201. But those radios are notorious for popping those .1uF caps. There are 2 of them in there along with 2 .05uf of the same type. They are all in the -82V supply, and should be replaced.

[gator7]

I remember a few radios from back in the 60's that had some color coded selectors. But i don't think i ever saw one with that many channels color coded.
Learn something new every day. Thanks Sandbagger.

[wd8nia]

Sandbagger's pretty much on the money. I became interested in CB while working part time as a dispatcher for Holly Hill Cab Co., and during the time when businesses were transitioning out of the band. There was an insert with my license informing me that some frequencies were still being used by businesses and to be avoided. I don't recall exactly which, but our cabs normally operated on channels 4 and 6, and on 22 when they were "scalping" fares up in Jacksonville. I presume that could apply to the "red" channels.

We were using the RCA Mark units back then and I was given one of them and a bag of crystals for wages owed when I quit. They were pretty good radios.

[Tombstone (R.I.P.)]

When I first started in CB around 1965 there were call or standby channels. The first such channel that I remember was channel 9. Then when REACT took over 9 the call channel was moved to 11. You made your calls on the channel using your call sign and once a contact was established you would check for a clean (unused) channel and switched to that for conversation. There was also a time limit for conversations. I believe it was five minutes and then you were required to remain silent for five minutes. It's been so long ago that I might be wrong on the limits, but no one paid any attention to that anyway. Sandbagger is correct on the channel allotments. Some were for business use, some for base to base, and some for base to mobile. I don't remember anyone bothering with that either, except stay off of channel 9. The colors didn't seem to be the same when comparing different radios. My Browning S23 transmitter is colored 1 through 8 red, 9 through 14 white, 15 to 22 red, and 23 and the blank slot white. A lot of people didn't have 23 channels, that's why most of this was ignored. I had forgot about the old RCA "Mark" models. My first radio was some Mark model with, I think, 6 channels of transmit and 23 tunable receive dial. They were darn good radios, tube type, and base or mobile by using the correct one of two power cords. Had a Turner M+2 mic on it. Later, in the 1970's, RCA made the Co Pilot model in 23 and the last, 40 channels. They were great mobile radios and for base, you could get a special cabinet, wood grain with a speaker in it. You just pushed the mobile radio into a cut out space in the cabinet and then it really did look like a base rig. Ah, the good old days.

Tombstone

[wd8nia]

Oct 18, 2010 0:07:23 GMT -5 Tombstone (R.I.P.) said:

When I first started in CB around 1965 there were call or standby channels. The first such channel that I remember was channel 9. Then when REACT took over 9 the call channel was moved to 11. You made your calls on the channel using your call sign and once a contact was established you would check for a clean (unused) channel and switched to that for conversation. There was also a time limit for conversations. I believe it was five minutes and then you were required to remain silent for five minutes. It's been so long ago that I might be wrong on the limits, but no one paid any attention to that anyway. Sandbagger is correct on the channel allotments. Some were for business use, some for base to base, and some for base to mobile. I don't remember anyone bothering with that either, except stay off of channel 9. The colors didn't seem to be the same when comparing different radios. My Browning S23 transmitter is colored 1 through 8 red, 9 through 14 white, 15 to 22 red, and 23 and the blank slot white. A lot of people didn't have 23 channels, that's why most of this was ignored. I had forgot about the old RCA "Mark" models. My first radio was some Mark model with, I think, 6 channels of transmit and 23 tunable receive dial. They were darn good radios, tube type, and base or mobile by using the correct one of two power cords. Had a Turner M+2 mic on it. Later, in the 1970's, RCA made the Co Pilot model in 23 and the last, 40 channels. They were great mobile radios and for base, you could get a special cabinet, wood grain with a speaker in it. You just pushed the mobile radio into a cut out space in the cabinet and then it really did look like a base rig. Ah, the good old days.

Tombstone

You're right, 'Stone....I'd forgotten about that....base to mobile, base to base, etc. It had even slipped my mind that our home channel was 19 and it was like a hornet's nest on the air when the truckers moved up from 10. That's the reason 10 has been my personal home channel since 1973.

This made me relive a huge chunk of warm and fuzzy past, so thanks.

[Sandbagger]

Oct 18, 2010 0:07:23 GMT -5 Tombstone (R.I.P.) said:

When I first started in CB around 1965 there were call or standby channels. The first such channel that I remember was channel 9. Then when REACT took over 9 the call channel was moved to 11. You made your calls on the channel using your call sign and once a contact was established you would check for a clean (unused) channel and switched to that for conversation. There was also a time limit for conversations. I believe it was five minutes and then you were required to remain silent for five minutes. It's been so long ago that I might be wrong on the limits, but no one paid any attention to that anyway. Sandbagger is correct on the channel allotments. Some were for business use, some for base to base, and some for base to mobile. I don't remember anyone bothering with that either, except stay off of channel 9. The colors didn't seem to be the same when comparing different radios. My Browning S23 transmitter is colored 1 through 8 red, 9 through 14 white, 15 to 22 red, and 23 and the blank slot white. A lot of people didn't have 23 channels, that's why most of this was ignored. I had forgot about the old RCA "Mark" models. My first radio was some Mark model with, I think, 6 channels of transmit and 23 tunable receive dial. They were darn good radios, tube type, and base or mobile by using the correct one of two power cords. Had a Turner M+2 mic on it. Later, in the 1970's, RCA made the Co Pilot model in 23 and the last, 40 channels. They were great mobile radios and for base, you could get a special cabinet, wood grain with a speaker in it. You just pushed the mobile radio into a cut out space in the cabinet and then it really did look like a base rig. Ah, the good old days.

Tombstone

More fun trivia.....

Yes Tombstone, you're right. Channel 9 was the original calling channel, and 9 thru 14 were the "interstation channels". Then they took 9 for emergency use, and made 11 the call channel, and shifted the interstation channels to 10 thru 15 (and 23). If you were making an "intrastation call", to one of your licensed units you could talk as long as needed to pass traffic. But interstation calls were limited to no more than 5 minutes, with a 5 minute quiet time before making another call (which is where the phrase "used up my nickel's worth" came from).

Ever wonder about the original Lafayette Comstat 25 and the HB525, which had the red channels "A" and "B" in them? Well, they were supposed to be the original Highway Emergency Locating Plan (HELP) channels, and the radios were manufactured before the FCC approved the plan, which they never did, so both versions of those radios were quickly changed to remove those channels and channel 9 became the sole "emergency" channel. Funny thing how the FCC was a lot more forgiving back then and they allowed radios to be made with "pending" channels in them relying on the honor system to keep people from using them before they were officially allocated. I can't see them doing that now.....

And then there was channel 23. Around my way, it was a total wasteland, with all sorts of bleeps and bloops and telemetry going on. 23 was a shared channel between class D CB, class "C" remote control, and business band. A class "C" station could legally run 25 watts there, so us puny 4 watt CB'ers didn't have much of a chance against all that racket. Most of us used 23 for testing and to talk to really close neighbors.

[Ronin]

For Sandbagger or others that are familiar with these Panasonic chassis radios:

I have found that the T-123B is slightly below frequency on both transmit and receive and about the same amount on both (channels that I checked were 4, 8, 12, 16 & 22). I know that the epoxy or paint that Panasonic used is a real bear to loosen to make adjustments. I was wondering since all channels seem to be off about the same amount (and on both xmit and rec.), is there a single crystal that could be bad or a component that I should check? I did notice that there is a trimmer connected to a single crystal on the underside of the chassis, but wasn't sure of it's purpose.

I plan to start replacing all the electrolytics and tube checking with it in the next couple weeks, so I might as well address the frequency issue right away if possible.

Thanks!!

[Sandbagger]

Oct 28, 2010 11:39:43 GMT -5 Ronin said:

For Sandbagger or others that are familiar with these Panasonic chassis radios:

I have found that the T-123B is slightly below frequency on both transmit and receive and about the same amount on both (channels that I checked were 4, 8, 12, 16 & 22). I know that the epoxy or paint that Panasonic used is a real bear to loosen to make adjustments. I was wondering since all channels seem to be off about the same amount (and on both xmit and rec.), is there a single crystal that could be bad or a component that I should check? I did notice that there is a trimmer connected to a single crystal on the underside of the chassis, but wasn't sure of it's purpose.

I plan to start replacing all the electrolytics and tube checking with it in the next couple weeks, so I might as well address the frequency issue right away if possible.

Thanks!!

Try checking frequency on channels 1,2,3,4 and see if they are also off, or just channel 4. It's possible that the crystal for the last channel in each group is the one that is low. If 1,2,and 3 are ok or off a different amount, then I'd look at the channel 4, 8, 12, 16, 20, and 23 crystal.

If all channels are off, then I'd suspect the 11.275 Mhz transmit mixer crustal which is located under the chassis. There is a trimmer attached to it that you can use to net the frequencies back in. But if the receiver is also off, then that won't correct that. There is an 11.730 Mhz crystal for the receive and it's attached to the fine tune. I don't think there's a trimmer for that.

[Ronin]

Thanks!

Here's what I have found:
Ch. 1 - 26.9631
Ch. 2 - 26.974
Ch. 3 - 26.9826
Ch. 4 - 27.029
Ch. 8 - 27.0526
Ch. 12 - 27.1025
Ch. 16 - 27.1526
Ch. 20 - 27.2029
Ch. 23 - 27.2526

All pretty close except Ch. 2, so I checked the other channels using the14.960 crystal to see what it looked like:
Ch. 6 - 27.0237
Ch. 10 - 27.0736
Ch. 14 - 27.1236
Ch. 18 - 27.174
Ch. 22 - 27.2237

Doesn't seem like it's off too much, but it is a little noticable. I will see if I can nudge the trimmer on the 11.275 xmit crystal and see if it comes up a bit. I would guess that the Fine Tune control itself acts as a trimmer for tweaking the receiver frequency. Do you think a second trimmer inside on the 11.730 receive crystal would bring the Fine Tune back to center slot so that it regains it's full range? If so, any suggestions as to what range trimmer?

[Ronin]

After tweaking the trimmer on the 11.275 crystal it brought all channels up a bit,, but it is maxed out. The channels that use the 14.960 all seem pretty much right on now on transmit (Channels 2, 6, 10, 14, 18 and 22), and the others are closer. When I start the re-cap project, I am going to try to gingerly scrape and peel that epoxy paint off with an exacto knife tip and see if I can free up the slugs in the coils to do a proper alignment.

[Sandbagger]

Oct 29, 2010 5:23:37 GMT -5 Ronin said:

After tweaking the trimmer on the 11.275 crystal it brought all channels up a bit,, but it is maxed out. The channels that use the 14.960 all seem pretty much right on now on transmit (Channels 2, 6, 10, 14, 18 and 22), and the others are closer. When I start the re-cap project, I am going to try to gingerly scrape and peel that epoxy paint off with an exacto knife tip and see if I can free up the slugs in the coils to do a proper alignment.

That pesky white "paint" on the slugs can be loosened with the heat from a soldering iron tip. Just heat up the slug (not too much that you melt the form), until the paint softens enough to turn the slug.

[Sandbagger]

Oct 28, 2010 13:26:02 GMT -5 Ronin said:

Thanks!

Here's what I have found:
Ch. 1 - 26.9631
Ch. 2 - 26.974
Ch. 3 - 26.9826
Ch. 4 - 27.029
Ch. 8 - 27.0526
Ch. 12 - 27.1025
Ch. 16 - 27.1526
Ch. 20 - 27.2029
Ch. 23 - 27.2526

All pretty close except Ch. 2, so I checked the other channels using the14.960 crystal to see what it looked like:
Ch. 6 - 27.0237
Ch. 10 - 27.0736
Ch. 14 - 27.1236
Ch. 18 - 27.174
Ch. 22 - 27.2237

Doesn't seem like it's off too much, but it is a little noticable. I will see if I can nudge the trimmer on the 11.275 xmit crystal and see if it comes up a bit. I would guess that the Fine Tune control itself acts as a trimmer for tweaking the receiver frequency. Do you think a second trimmer inside on the 11.730 receive crystal would bring the Fine Tune back to center slot so that it regains it's full range? If so, any suggestions as to what range trimmer?

If you look at the schematic, you will see that both the 11.275 Mhz and 11.730 Mhz oscillators have variable caps. The trimmer sets the TX frequency, while the fine tune takes care of that function for the receive oscillator. You probably could shift the range of the oscillator by dropping a fixed cap in parallel with the fine tune cap, assuming that is the right way to go. It's probably a little easier to replace the crystal, as those frequency crystals are fairly common. It might be helpful to get a high impedence proble and hook up a frequency counter to those oscillators to see if they really are off. It may just be that the 23 Mhz crystals are all off. I don't usually see 6 crystals go off frequency by nearly the same amount, but it's possible. The L7 coil slug may shift frequency of the 23 Mhz oscillator, so when you align the radio, give that a try.

[gator7]

Wow, this thread brought back some memories of my Couier 23 and my Couier 1M mobile. I remember a time when we had channel police who would let you know if you didn't play by the rules.
In western Connecticut we had a club called Marc V that used channel 14 as our club channel.
Yes we did a fair job of keeping everybody straight. Of course you always had one or two who would try to ruin it for the rest. Once the call channel became ch 19 it started to go down hill from that point.
To bad we can't turn back the clock.

[Ronin]

Thanks Sandbagger, I will give that a try with using a solder tip to loosen the 'paint' and the L7 adjustment. What I did find today was that some of the odd, off-frequency sounding audio is from a weak local oscillator tube. All the tubes in the T-123B are the original Matsushita tubes, and since I have a Comstat 35 with some newer tubes in it, I started swapping tubes to test if one was better than the other. I swapped the 6GH8 out and it is working much better. Since L7 is the adjustment for the local oscillator, I am sure you are right on the money with your assessment.

Overall, the Robyn and Comstat are about the same in that they are both slightly low in freq, but the Comstat got better audio reports in the past. At this point I am going to wait until I re-tube and re-cap the Robyn before I go much further. I'll post how I am coming along with the project in the next couple weeks.

And Gator7, Having these older tube rigs to operate and tinker with actually helps to sort of turn the clock back a bit.

[zman]

Im suprised how much those old Robyns go for on Ebay! The last one i saw went for 135.00!!!! I remember seeing them at local swaps and garage sales selling for peanuts on the doller. I saw one for sale at a local flea market for 5.00 a few years ago.

[cbrown]

As the nostalgia kicks in, the prices rise. Also once people start seeing a demand, they'll raise prices.

[zman]

Maybe ill put mine on there!!!!!!

[zman]

Even the junker non working rigs are selling! I just sold a non working parts rig Robyn T 123B as well as a junker lafayette comstat 35. People are snapping up these old tubierigs right and left.

[cbrown]

Might be a nice side business if you know where to acquire some cheap tube rigs.

[zman]

Ive been getting them and fixing them up. The ones that are too far gone i sell for parts.

[cbrown]

Sounds like a good plan!

[zman]

Yes it is. However the ones that work im keeping. My girlfriend says im hoarding radios, LOL!!!!

[cbrown]

I get the hoarding thing all the time, and I guess I do. But like you, I usually just keep the working ones, although there is usually a 'spare parts' box nearby.

[zman]

I have a Tram titan II that lost its receive that im thinking about either getting fixed or sending to someone.