SCR S838

[cksnowman]

Team:
I have a Diehard battery charger that I decided to fry awhile back and I took out an SCR with the label S838- I found out that the company is called Teccor and they were bought out by littlefuse. I called customer service at Schumacher Electric Corp and they tried like crazy but still couldn't get any results. I have also found out that the possible specs are 800V 35A but not 100% sure- if someone knew where I could order one I would appreciate it!

 

[duke37]

I doubt if you need anything special, with a 12 or 24V charger, 200V would be adequate.
The current specification should be several times the charger output current.

 

[john monks]

Can you supply a make and model number of your battery charger.

 

[cksnowman]

the actual part number on the Diehard battery charger is a 200.71223 or a 20071223 (depending on who you talk with)
there is another charger that is a 200.71224 that is just about the same but higher current so probably has the same part in it.
the battery charger is made by shumacher electric corporation, and just relabeled by sears.

Question for the team: Are the actual pinnouts basically the same on SCR's??? can I just go get an NTE or whatever brand of SCR with the current capabilites??? Don't work with SCRs much.

I appreciate you all helping.

 

[john monks]

I can't find a datasheet for the s838. 800V @ 35A sounds like a reasonable value so you might try 40TPS08APBF scr from jameco. This is 800V @ 55A. Or you might remove the entire module assembly and replace it with a bridge rectifier with a big 12V light bulb in series making a trickle charger.

 

[cksnowman]

I appreciate the feedback- interesting on the 12v light bulb idea- but this charger already has a microprocessor for trickle charging... I'm concerned about the pinout- should I just solder it in there and see what happens? I really like to know that before I go for it...

 

[Kevin Callen]

I to have the same battery charger and as with the other fello, i can't seem to locate a replacement for the SCR S838. Can someone tell me a formal way to test the component? By the way the center leg of this unit has been clipped off!!

 

[Tha fios agaibh]

Kevin, You can use an analog ohmeter or continuity tester to test a scr. I prefer to use a flashlight type continuity tester because it has two batteries and will output 3v to trigger larger scrs.

The Cathode (K) needs to go to neg lead, Anode (A) will go to positive lead, and then briefly touch Gate (G) to Anode or positive.
This will trigger the scr and the ohmeter will read zero or a few ohms, or the light will go on.

If your scr has the center lead clipped off no testing required. It's scrap.

 

[Minder]

Teccor/Littlefuse can be obtained from Digikey, I have picked up several to replace the Teccor original.
M.

 

[duke37]

The centre leg is not needed if the tag is the same connection. Clipping it off saves a little in assembly.
Theis does not work of course if the body is isolated.

 

[Tha fios agaibh]

Ahh, good point duke37. The mounting tag is connected internally. Center pin must be the cathode because the heat sink is neg.

 

[duke37]

When I used a SCR to drive my coil winder, I connected the heat sink to the positive supply .

 

[Tha fios agaibh]

Right again duke37.