Old Craftsman 2/10/50 charger/starter not functioning properly

[68gtxman]

OK. I bought this unit new in the early 1980's so I got my money's worth out of it. I still use it as a manual battery charger, but the timer and switch between 2 amps and10 amps don't seem to be working and it has been this way for about 20 years. Today, I finally broke down and took it apart to see why the timer switch didn't seem to be functional. After opening the switch, I see that it is opening and closing the contacts correctly with the switch's position indicator. I tested the main switched power wire and I see that it is continuous with the side that's on the other end of the contacts, whether the contacts are open or closed. Ruh roh! I am a mechanical engineer and I don't normally get deep into circuits, so I've about exceeded my circuit skills. I would guess that whatever the thing is in the glass vial (just right of center in the bottom photo) is the problem. It seems to be an electrical switch that is supposed to disconnect at some point but it is failed in the closed position.

Does anyone know anything about these things or their failure modes???

 

[Yatzee]

View attachment 421802 View attachment 421803 View attachment 421804
OK. I bought this unit new in the early 1980's so I got my money's worth out of it. I still use it as a manual battery charger, but the timer and switch between 2 amps and10 amps don't seem to be working and it has been this way for about 20 years. Today, I finally broke down and took it apart to see why the timer switch didn't seem to be functional. After opening the switch, I see that it is opening and closing the contacts correctly with the switch's position indicator. I tested the main switched power wire and I see that it is continuous with the side that's on the other end of the contacts, whether the contacts are open or closed. Ruh roh! I am a mechanical engineer and I don't normally get deep into circuits, so I've about exceeded my circuit skills. I would guess that whatever the thing is in the glass vial (just right of center in the bottom photo) is the problem. It seems to be an electrical switch that is supposed to disconnect at some point but it is failed in the closed position.

Does anyone know anything about these things or their failure modes???

Your time must be worth nothing to try and resurect that dinosaur to something even near reliable, either that or your wallets full of dust. Try this:
https://5to10bestreviews.com/best-battery-tender-plus/

 

[68gtxman]

Your time must be worth nothing to try and resurect that dinosaur to something even near reliable, either that or your wallets full of dust. Try this:
https://5to10bestreviews.com/best-battery-tender-plus/

I hate throwing away things that can be salvaged and reused. I have more Battery Tenders than I need, but I don't have a fully functional 10amp charger or a 50 amp jump starter device. This charger can do both very well, if it was fully functional. It nearly kills me that it is probably just a simple little $0.59 component that is preventing it from being fully functional. Do you take pride in fixing things most people just throw away? I do.

I'm sure someone already solved this problem.

 

[Billccm]

It looks as if it has a Sylvania logo; it may be a ballast tube. See if you can get a number off the tube. I have a Sylvania tube specification manual for design engineers and might come up with something for you.

I also recommend a good cleaning of all contacts and switches with DeOxIt. I can't say enough good about that product and could write a book on what I've repaired using that stuff over the years.

 

[Billccm]

Do you take pride in fixing things most people just throw away? I do.

Back in high school I took vocational Radio and TV repair (yes, there was such a thing as TV repair back in the day). For extra credit, the teacher got us jobs fixing things at the Salvation Army as a volunteer. I was amazed at what was thrown away that could be fixed so easily. Even in the late 1970s when microwave ovens were $700 we were fixing them for a loose door safety switch failure. Just a loose screw on a switch and the microwave was back in service. Hair dryers and toasters were fixed with a $0.14 thermal fuse. Radios with a cracked solder joint were back in service for no cost other than the time. That volunteer job gave me experience to land a job in the TV repair business, but also taught me to 'keep it simple' when diagnosing problems.

 

[oldbee]

Get ur model# and lookup online. Almost every thing on there. Looked up my dad's 15yr old lawn tractor online.

 

[oldbee]

Wiring schematic would be helpful.

 

[Photon440]

Is that glass tube a mercury switch?

 

[oldbee]

I thought that also but don't see any mercury in there.

 

[68gtxman]

Is that glass tube a mercury switch?

I thought so too, but as was said, there is no mercury in it and no reason for having a mercury switch either.

 

[oldbee]

Think photon&i were thinking a 'tip over' switch even though it's not a space heater.

 

[Mike67]

Hard to tell with the glare, but the symbol appears to be of a diode, Ive never seen one in a vacuum tube...

 

[idrivemopar]

Maybe a thermal cutoff switch?

 

[oldbee]

Idrive good idea.

 

[68gtxman]

Diode makes a lot of sense. I'll have to break out the magnifying glass to see what is printed on this glass vial.

 

[68gtxman]

I found a part number on the glass vial thing: SB708E3H. Though a Google search didn't turn up anything.

The symbol wasn't too clear. Though it had a triangle and a line, the line wasn't aligned with the pointed end on one side.

It did look like it had electrical contacts inside of it and they seemed to be closed. A continuity test showed that it was indeed closed. Maybe they fused together when they instead should open and close depending on the switch position?

Does this extra info help any electrical guys out there?

 

[68gtxman]

My charger has a built in timer so it is a little different than this one.

The glass vial thing is attached to the heat sink/diode assembly, so the glass vial thing is probably the diode.

Does anyone have any thoughts as to whether this may be the problem component?

 

[Billccm]

I still believe that this is a ballast tube, but I cannot find it in my tech manuals. The logo is from Sylvania circa pre 1970; see picture.

Let me research this more and I'll get back to you.

 

[Billccm]

If you have a shorted, or even leaky diode your charger would be sourcing AC, which is death for DC batteries. A ballast tube is like a voltage dependent resistor, which was used in many chargers in the 1960s. Yours seems newer than 1960s, so I just cant say for certain what the tube is, yet.

 

[68gtxman]

I still believe that this is a ballast tube, but I cannot find it in my tech manuals. The logo is from Sylvania circa pre 1970; see picture.

Let me research this more and I'll get back to you.

View attachment 423264

Thanks! From seeing the Sylvania symbol on the manual, that's exactly what the symbol on the glass tube is.

It seems that the diodes are mounted directly to the heat sink board (from looking at various parts for sale and YouTube videos), so the glass vial device is probably not a diode.