Tag Archives: Collins 30L1

Collins S-Line Mostly Returns

A load of Collins S-Line gear

After MUCH work and TLC by Chuck W9KR, the majority of both of my Collins S-Line stations was ready to pick up.

The 32s1 transmitter is only major piece left behind for final work, as it hasn’t been behaving as expected on each band.

On a temporary basis the RE (Round Emblem) late production transceiver – KWM-2/A with 321B5 Second VFO – and station components (30L1 Amp, 516F2 Power Supply and so on..) will be set up where my Flex-6600M runs. This will let me work the rig lunch hours and after work, as I would like to let the station run for a bit before hauling it out to Washington Island.

I’ll do the same with the 32s1/75s1/30L1/312B4/516F2 WE (Winged Emblem) station when the transmitter is done.

The work Chuck W9KR did is monumental. Recapped, Upgraded, New tubes as required, new parts as required, decades of dust & grime removed, New 572b tubes, in certain cases mouse infestations sign removed, tech bulletin upgrades, CCA upgrades, and a few Chuck W9KR upgrades – especially in improving the reliability of the 516F2 power supplies.

The gear arguably should work better than when new, should be reliable and should have all that great Collins sound.

Quietly I cannot say enough with the detective work and bench work of Chuck W9KR.  I realize that I have so much to learn just in order to fully understand all the goodness he baked into these radios.

Lots of Collins fun ahead for me working the airwaves with refreshed vintage gear!

73

Steve
K9ZW

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Handling the Voltage Multiplier Issues with High Line Voltage and Vintage Radios

What is “normal” household line voltage?

What is acceptable to our Vintage Radios?

Without getting into a deep discussion the voltage delivered to the average American home has gone up since the pre-WWII’s 110vac, then post-war 117vac is now 120vac.

The current standards are:

Yet our old radios might be intended for less.

My two Collin’s S-Line Stations definitely were intended for a bit lower voltage than 120vac.

Inside the S-Line components voltage can be multiplied to produce Vacuum Tube level voltages by step-up transformers.

If the original design took say 110vac and upped it to 800vac, it is a 7.273 multiplier.  (The 800vac is just a value I picked, as there are several stepped-up voltages in use in a S-Line station.)

If modern power is suddenly say the maximum allowable of 120vac  plus 6% for 127.2vac, the 7.273 step-up transformer is pushing out 925vac, which may be above the maximum safe voltage for a particular application.  Even a 120vac line voltage will he 873vac after the step-up.

What the Collins designer originally really wanted was that 800vac voltage they designed for, which would mean we have to figure out a way to limit the line voltage to 110vac.

Well you cannot call up your power company, as ask them to “turn my voltage down for me, guys” That isn’t going to get you anywhere.

Here is the solution:

Actually what is in those boxes are these:

Medium Duty Variac Transformers where we can “dial down” the output voltage to that ideal 110vac area.

The capacity (2KVA) is sized to handle a 516F2 power supply and 30L1 amp, and the build quality is solid enough to do shack duty with ease.

I bought these from an eBay seller, though the identical units were also available on Amazon, with the 16% Amazon cut added to them of course.

Each S-Line setup is getting its own unit.  The third is for other projects.

73

Steve
K9ZW

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Collins Progress Update 1

Some in progress pictures as Chuck W9KR does his magic on the Collins 32S1/75S1 station.

Digging in at W9KR’s very well equipped workbench

Testing found some weak and failed tubes, all which are being replaced. I had bought tube kits for some of the units, and others have been sourced. All told about 8-10 tubes across the equipment are being replaced.

After a prolonged period of increasing voltages controlled by a variac, good meter readings

Prolonged means a lot longer than I would have thought, a gentle process.
Continue reading

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Collins S-Line Station Interconnects and Connects….

For those of you who grew up with separate Receivers and Transmitter what I am working through is likely going to get a “Duh K9ZW, what did you think?” response, as I am learning all about the interconnects and connections of a Collins S-Line Station.

Black-Box radio users are accustomed to hooking up the power, the microphone, maybe a headset, the ground, and the antenna. If running an amp, tuner or SWR meter there is only a very few additional connections additional.

Not so with an S-Line Station. While possible to run the station with fewer interconnects the classic set up when a 30L1 Amp and 312B4 Station Control are added, the full complement is a whopping 18 cables!

Collins S-Line Full Interconnection Chart

Collins S-Line Full Interconnection Chart

There are four low-power RF connections using RG-58C/U terminated RCA-to-RCA. Yes those RCA connectors like a budget speaker system uses.

Then there are ten RCA-to-RCA patch cables, plus one RCA-to-bare-wire to connect your CW key.

Your microphone will need to terminate with a PJ-68 plug if your setup is a “S-1” like mine.

You will need an odd RCA-to-90 degree N-Connector RG-58C/U cable if you want to skip the amp. May as well get one and have it on hand in case I want to operate sans the Amp.

Otherwise you need a N-connector-to-90 degree N-Connector RG-8/U cable between the Amp and 312S4 meter. To get from the meter to your usual station connections (Antenna Switches, Tuners and such) you will need a 90 degree N-Connector to usually a PL-259 RG-8/U type cable.

If you add that all up, it is actually 19 cables, but the odd RCA-to-90 degree N-Connector RG-58C/U cable is a spare if you want a no-amp configuration.

The high count excludes a ground and three electrical plug-ins! And there is a cable from the 516F2 Power Supply to the 32S1 transmitter as well. If we were really counting we should include the Twisted Pair from your POTS Telephone Line to the 312B4 if the Phone patch were hooked up. That I think brings us up to 25 cables plus the spare one for that no-amp reconfiguration!! Whew!

As I had on hand but half of the needed cables, I’ve gone internet shopping to fill out the cable set I actually needed.  Have sorted out adding the cables I need with again Mark KE9PQ supplying the additional newly fabricated cables I need and some spare/optional cables I wanted.

I should mention not all connections are on back plates, with several of the RCA connections inside the radios on the chassis. The units have a nice pass-through to allow the cables to get inside.

The 90-degree part on N-Connectors is to do with the limited space inside the 312B4. Straight N-Connectors will work if the coax is flexible enough.

While I’ve not yet put the Collins S-Line station on the air, I am having fun learning about another time’s technology in Amateur Radio.

73

Steve
K9ZW

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Rounding Out the Collins S-Line Station – Found a 30L-1 Amp

Thanks to Gary K8BKB my Collins S-Line vintage station is gaining an amplifier.  Gary had a spare 30L-1 of a similar vintage and style as the rest of the station, so it seemed a natural.

Collins 30L-1 Amp

Collins 30L-1 Amp

Still hoping by the end of September to be regularly on the air with this Vintage Collins S-Line station all running – 75S-1 Receiver, 32S-1 Transmitter,  30L-1 Amp, Speaker, Power Supplies and Station control.

Photos of the completed S-Line station will follow once it is all up.

73

Steve

K9ZW

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