Hello everyone, it's been a while since I've made a post in this forum. I hope everyone is doing well. A long time ago (with the gracious help of y'all), I set up and got my San Bar 1A2 KSU up and running. Since then, something has happened to it. It's been sitting in the closet for at least 8 months now, and I finally have sat down again to try and figure out what happened.



Thanks in advance everyone!

Pictures:

Line Card:


KSU:


66 Block:


YouTube Video:

Click here

Your problem may not be the interruptor but rather the power to run it. Both the lamps and the interruptor run on 10v AC.

You need to check the output of the power supply to see if it's putting out 10vac. I'm not familiar with the Sanbar KSU but it should have a spot whe you can check output voltages. 10v AC may be listed as LB (lamp battery).

Sam

Good idea! So I just use a voltage meter across the lamp leads?

No I think he said to check the output of the lamp 10 ac at the power supply.

What Jim said. Check all voltage outputs directly from the power supply.

If the supply follows conventional 1A2 standards then it should have:
10V AC ( for lamps and the interruptor motor)
-24V DC - filtered (A Battery, for intercoms)
-24 V DC - unfiltered (B Battery for relay operation)

There should be a place to measure them, either coming directly out of the power supply, or very possibly on one of the 66 blocks.

Sam

Sorry for the delay in my reply. I will look into this when I get a chance and I will post an update. Thanks for your help guys. Merry Christmas to you!

Update: I have finally figured out the problem, and it's worse than I thought. It turns out, I must have misunderstood how to connect single line telephones to my 1A2, so since I got it I have been using the A lead ports for my Tip and Ring. As far as I know, all of my system's components are in working condition still, but all my KTU's are done for good. I'm disappointed for sure, but KTU's seem to be readily available on eBay, and I'm sure at some point I can pick one up and get my system working again.

Shame on me for my ignorance! But I suppose I can call it a lesson learned the hard way.

Thanks for all the relentless help everyone on here always gives me!

If I understand you correctly:

Putting the T & R of a single-line set across the A + A1 leads should not have caused any damage to the line cards. Is that what you did? I suspect that you did something else if your KTU's are fried.

You would be advised to do some research and educate yourself first, before attaching wires to things. Do you have the practice (instruction sheet) for that KSU? If not, we can easily point you in the right direction on the web where you can learn about 1A2.

The line cards (400-type) are free, essentially. Don't pay more than a few bucks for them. I have a few I can send you for the postage.

Sorry for the delay, I've been quite busy the past few days.

To answer your question:

I did exactly what you stated. Since you say that this wouldn't cause any damage, I'm honestly not sure what happened to the line cards now. I may have crossed two wires somewhere and damaged something, but knowing that most 1A2's could survive just about anything makes me doubt it (although they aren't indestructible).

In response to your generous KTU offer:

At the moment, I'm quite satisfied with the Merlin, and with the amount of electricity I've been told by my parents that the 1A2 consumes, I don't think I'll be messing with it anytime soon (which is sad in a way).

I hope at some point, possibly during the summer, that I can fix it and get it running again. I sure do miss seeing those bright line keys!



Thanks for everyone's help once again.

You might want to clean up the termination block, start from the right side not the left, your white orange and yellow slate pairs are reversed and it looks like I can see bare wires as if you punch down tool didn't cut the wire, are you using a punch down or a screw driver?

I had a punch down at one point, but I honestly cannot say what happened to it. I just use a small screwdriver, but the wires always are firmly "punched" down.

t g 10, I get to jump on you 1st! Take it from one oldster, NO SCREWDRIVER does a RELIABLE, CORRECT, punch down. Break down and buy another punch-down tool.

No self-respecting "telecom guy" would ever punch down with a screwdriver!

Heck, I've got BIX and Krone tools that I've only used one or twice - get the right tool for the job!

Hello all:

I know this is an old thread, but I wanted to give you all a very late update on this. I just fixed the key system on Monday-turns out, one of the flat key system fuses (the kind with the thin wire) had just corroded to nothing, so I replaced it with a piece of wire, and now my lamps and interrupter work fine.

Thank you Silversam for helping me pinpoint the voltage issue!

Scott

Ive got some of those fuses and the replacment fuse wire that you solder onto the fuses if anybody can use them. Dont think Ill use them.

Well, I won't say I've never used a piece of wire to replace a burned out flat fuse- but I always replaced it with the right size fuse when I got one. One good tip - use a piece of thin solder to replace the fuse - until you get a real fuse to replace it with. The solder will melt away in a problem - hopefully before your power supply goes up in smoke.

Sam

I may have a replacement fuse for your KSU. What's the specification of your burned out fuse?

You can always use a standard Buss or Littlefuse pigtail fuse of the correct amperage. Just wrap the leads around the screws. If you replace them all you can dress them so it looks nice. I know it isn't authentic but as Sam says it beats burning something up.

-Hal

"turns out, one of the flat key system fuses (the kind with the thin wire) had just corroded to nothing, so I replaced it with a piece of wire, and now my lamps and interrupter work"

"Up Nort" we call a thin wire a "Johnson" or "Anderson" bar named for the two Scandihovian inventors who taught it up over a couple dozen Grain Belts by golly.

The correct technical term is "no-blo".

If you do use a piece of wire, and the short circuit recurs, the full-wave bridge in the power unit will burn out. Then you have to go to Radio Shack, buy a new one, and replace it. That's what we did at New York Tel Co to avoid having to remove all the wires and replace the power unit with a new one. Much too much work. Easier just to break the rules and install a COTS unit.

You take the 18 Vac output off the front of the power unit and feed that into the bridge. One side of the output gets grounded, and the other side gets connected to the -24 Vdc screw.

Thank you everyone for your responses.

I will take a look at the rating of the Key System when I get home. It is a San/Bar 6630B model.

Okay everyone- here are the fuses. They are located under the interrupter on my key system.

PM sent.

Sam