NPN Transistor Part ID

Kaz,

I did a quick search on a couple of sources I have access to, with no hits.

To put a picture in a post, just click on the little green camera in the editor toolbar. I think it will handle .gif, .jpg and .png for sure, maybe others. Please do post a pic, it might help with the search.

Tom

here is the pic

It looks plausible. But a caution: even if it's basically the correct part, it is conceivable that the H and F are breakdown, trigger and/or thermal selections. (I think the original part is in a copper case - the "replacement" looks more dubious)

If there is a controller that still has a live device in it, I'd be inclined to do some low-voltage diode testing to confirm it is a thyristor, and then high-voltage testing with a large series resistor to check the breakdown Voltage.

Good luck...

The 8047 is the date code, 1980, 47th week. The 'H' may be a product run identifier. So far, I have not found anything on the G0857, it may be a house number which are usually difficult to identify. I'll keep looking.

I agree on the date code. I was unable to find anything in my 1975 RCA Power Transistor Manual. I suspect it is an OEM number, specific to whoever manufactured the controller.

I assume it is blown... If there is still a good one in the controller, measuring the inter-terminal voltages on the diode scale of a DVM can help identify the type of device.

Could the number be not G0857 but 60857? Would make more sense.

Hello Kaz,

An interesting one, I have done a few searches and found that RCA8766 series may interest you, its a darlington range with 350 to 400 v and 10 Amp capability.

Regards,

Dave Reynolds.

Thanks guys for trying.

Got some suggestions from another forum that it could be 60857, not 'G0' which would cross to SK3502 and NTE5513

What do you think?

That damn thing is 30years old.

I assumed it's SCR and rigged it up with NTE5529 (600V & IT=25A) but it blew instantly.

Will have to probably do revers Eng. and try to figure out what could work there. Looks like there is a driver transformer in the BASE/GATE? circuit, suggesting SCR..

will see..

Something caused the original to blow. have you checked for shorted capacitors, diodes, etc.? Whatever blew the original could be blowing the replacement.

did a quick check, did notice anything in particular. I'm waiting for SK3502 to arrive and then I'll do more checking, rev. eng and will try to simulate the load an the bench and fire it.

Will report on the progress

According to an old RCA cross reference, the 60857 (and it does look like that first character could be a 6 instead of a G) is a 600 volt, 5 Amp SCR which does cross to the old SK3502 substitute. I have not been able to locate an actual data sheet in my archives as yet. If that is a 'G' instead of an '6' then it is a house number and only the manufacturer has the data on it. Unfortunately, house numbering of standard parts is, and has been, a fairly common practice and also a foolish one on many counts.

I have a fairly large RCA semiconductor data manual around here somewhere which might have the 60857 in it, haven't found it as yet. My archives have been scattered all over the place (thanks to my dear wife who thinks it is junk!)

may talk to your wife!

Thanks for helping.

Hi, to all.

Maybe you can work out what the device is from the drive circuit.

If it is a thyristor then maybe it has a bridge circuit, since the grinder works on AC voltage and thyristor will only conduct one half of the cycle. If there is no bridge, is it a triac device ?

If you cannot find a suitable replacement then there are plenty of phase control PCB kits. out there to build a new control circuit Quite cheaply.

thanks to all that helped. Finally I put an SK3502 and everything is well.

Thank you for the feedback.