I recently got a 1033 transformer that looks to be in good shape. It has a replacement cord, and a resistor (I think) soldered in. When I check the voltage across the posts it is just about right on. However, when I put any type of load (even just a light bulb) across the A C (constant voltage) or U A (variable 5 to 16 volts), the voltage immediately drops to about 6 volts. If I put a heavier load on the circuit breaker opens. Any idea what is wrong?
The resistor soldered in to the cord is limiting the current to the transformer. With no load, it will show full rated output, with any small load the output will drop drastically.
Replace the cord and leave out any & every kind of resistor.
A picture of this mystery resistor would be interesting to see, too.
Rob
I think we should find out what and where the “resistor” is first. It may be the resistor for the whistle circuit and it may be a diode replacing the copper-oxide whistle rectifier. It could even be a TVS.
Whomever worked on this transformer did very neat work with the new cord and soldering in the resistor. The resistor or diode (only marking on it is SK 3639) is on the left side and looks to be tied in with the rectifier. So yes, I think it may be a diode replacing the rectifier.
Given that, what about the voltage problem?
Here are the specifications for the SK3639:
Silicon Rectifier
V(RRM)(V) Rep.Pk.Rev. Voltage=200
I(RM) Max.(A) Reverse Current=250u
I(FSM) Max.(A) Pk.Fwd.Sur.Cur.=400
V(FM) Max.(V) Forward Voltage=0.9
I(O) Max.(A) Output Current=6.0
Package=Axial
Military=N
It looks very much like it is replacing the copper-oxide rectifier.
I would try bypassing the circuit breaker, as an experiment. If the transformer works normally then, replace the circuit breaker with a 5-ampere automotive breaker.
The circuit breaker looks blackened around the adjustment screw. I tried bypassing it as you suggested and the transformer seemed to work correctly. So I would take the old circuit breaker out and put in an automotive breaker? I guess I need to see an automotive one to have an idea how that would work.
Thanks for your suggestion, as it does point to the old circuit breaker as the problem. Do those fail in some way often?
Not often, but it happens.
There is no need to take the old circuit breaker out. Just run a wire from the B terminal to the new circuit breaker and move the wire that is soldered to the circuit-breaker terminal on top to the other terminal of the new breaker. You’ll need to find a space to tuck the new breaker into. Use an automatically-resetting type.
Are these circuit breakers at most auto parts stores? I looked on line and didn’t see much.
Did you get your tranformer working? I am having a similar problem where the train will run, but after about 20-30 seconds the train starts/stops. I pulled the transformer cover and noticed some arch on the circuit breaker. I think that was creating heat and moving the metal lever part of the breaker away from the set screw. I tightened the set screw which means the metal lever (wish i had a better term) can’t move away from the set screw as quickly. Appears to be working as the train ran longer. But this doesn’t solve the problem of the circuit breaker from having this sparking. Any ideas on a solution?
I thought about overriding it and i bough a automotive blade fuse holder to run between the track and the transformer, but wondering if there are any better methods. The one mentioned earlier in the thread sounds good, however, i couldn’t find any automatic breakers at 5a…lowest was 10.
Yes, I just did get my transformer working tonight. I found a 5 amp automotive auto-resetting circuit breaker at an auto parts store and used it to bypass the original one as suggested in the earlier post. It seems to work fine now. My problem had been it I tightened the screw on the circuit breaker it did provide full voltage but then started to arc and smoke. The auto 5 amp seems to work fine, and I did try tripping it a few times. It did trip and would reset itself in about 5 to 10 seconds. So, I think my transformer is fine now.
Bob, I’ve been meaning to ask you this question about automotive circuit breakers, both auto-resetting and push-button resetting–they’re designed for DC systems in cars, but our Lionel (and other) transformers are AC…so, do they work OK in this application? Just something I’ve been wondering about. Thanks!
That’s a reasonable question. There are two considerations with regard to AC versus DC:
The heating action in the bimetallic strip that opens the circuit is the same for AC and for DC, so there’s no problem there.
When the circuit breaker trips, the arcing is actually less with AC than with DC. Because the AC waveform goes through zero 120 times each second, any AC arc is quickly extinguished, while a DC arc can last much longer and do more damage to the contacts. This effect more than compensates for the fact that we use voltages a little more than the 12 volts that the breaker is rated for.
Mark- Would you happen to have a picture of the repair? Also, what store did you get the circuit breaker? I tried advance and oreilly’s with no luck
What’s the exact automotive circuit breaker you’re using? I have several 1033 I use for accessories, sounds like a useful modification. I’d like it to fit inside the case…
Here’s a link to NAPA for a 5 ampere breaker: http://www.napaonline.com/Search/Detail.aspx?R=BK_7823010_0282393606
I don’t have a picture but the breaker looks like a slightly large automotive blade fuse. I got mine the first place I happened to look, Farm and Fleet in Urbana, Illinois. They have a large auto parts section. I bought a universal circuit breaker, 5 amps, by the Littlefuse company of Des Plaines, IL. Says made in the USA. It is 12 volt, DC type with extra long brass snap-off tabs. I just soldered to the tabs and there was plenty of room on the left side to tuck it in after I put electrical tape over the bare connections. I was just using the transformer and it continues to work great.
My Littlefuse Inc. breaker looks just like the NAPA one, but cost just $2.79.
Yes, the NAPA price is pretty high. I have usually paid only a couple of bucks. It was the first example I was able to find on the web.
Those terminals will also take quarter-inch Fast-On quick-disconnect connectors, which is what I use. The breakers are meant to plug into the same sockets as fuses.
Bob, I too have brought “out of the closet” a sixty year old 1033 transformer and the trainset I received for Christmas 60+ years ago. My folkes had it stored in the basement for thirty plus years and then I have head it stored for another 20 plus years. I found that the headlight on the loco, a 2026 model, worked, and the light in the caboose worked intermittently, and nothing else worked.
After reviewing many posts on subject transformer, I replaced the CB with a 5 amp automotive breaker as you had suggested to others. I also resolderend bad solder joints for various wires. I find that the transformer for the most part seems to put out appropriate voltages but have discovered some deterioration/damage to the transformer winding at the bottom. It is not clear that it is affecting the operation, but somewhere along the line this baby was fried or toased somewhat and that may make it unsafe.
At any rate, then I moved on to the tender and replaced the two wires inside it which were totally useless. Testing tender on single track section powered with the 1033 I found that the whistle now operated, but it seemed to get stuck in on until I moved the control beyond the normal position toward the direction change position cutting the power. I may have more work to do there.
Now I have moved on to the engine/loco, thought to be a 2026 model. I downloaded the pdf files from Olsen Toy Library and studied same. I figured out how to remove the engine assembly from the loco frame. I have question on the SHOE removal. I have not found forum for engines, yet, or I would post there. So perhaps that’s the question first…how to find the engine repair forum?
Lastly, back to the transformer. The rectifier and resistive wire seemed to be a source of problems for
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