Failed Motorola 10261 ... transistor?

[eccerr0r]

The 3055 didn't like being paralleled with the 10262's... Not sure I want to burn all my 3055s by replacing them all so that the paralleled transistors match in type...(apparently the emitter resistors aren't sufficient to allow the 10262 and 3055s to be paralleled?)

Aoso have a whole bunch of transistors that I have never identified fully... Have one typed "7652" though it too has cut leads and would need prosthetics to fit in the socket vacated by the 10262's...

Also have PMD1702K and PMD1602K's ... and some of the 2n605x series. These are all darlingtons which I'd have to redesign the circuit somewhat to use...

[CapLeaker]

Stick with the 3055 then.

[eccerr0r]

most of the TO-3 pile I have are germanium PNP or Darlingtons for some reason. Have a few HOT NPNs (i.e. high voltage) and the 2N3055's.

I suspect the SCR and MOSFET TO-3's will never work...

[CapLeaker]

What else you got on transistors?

[eccerr0r]

and yeah, if the 10262 is more like a 2n3771 then yeah, the 2n3055 is probably not a proper sub. Then again perhaps the 10261 is a 2n3055 sub. Argh, whole point of the exercise is to find specs :\

Still haven't tried putting prosthetic legs on the 2n3771. Hmm. To start sacrificing other psus for parts or not...

[eccerr0r]

Yeah I ended up tracing the pcb a bit and realized that the circuit indeed was a series pass emitter follower circuit.

I might have to rethink this a bit, after trying to run the PSU at ~120 watts output, the 2n3055 started heating up a bit while the actual 10262 felt a bit cooler. Unfortunately I don't have any 2n3773's to try, and the pins of the 2n3771 I have are way too short (since it was a pull from a direct PCB mount with no heatsink), may have to add on some prosthetic pins and see if it will still fit and work...

[CapLeaker]

If it was a popular part...why is there no documentation about it and why are some wrong...?

hmm...calculating backwards I need a transistor that can handle 4 amps... and already in my spare parts bin...

While some Motorola parts are documented well, others are not. NTE / ECG is not 100% correct. Why I don't know, but had a run I'm with a Motorola MSR2000 power supply where the pass transistor failed. One of my friends used the NTE part suggested and I used a different part that I chose by my own judgment. His went and mine was fine. I sent him some of my transistors and all was fine. That was back then when you still could buy NTE.
I hate the Motorola parts numbering scheme. Some are easy to identify others are just about unidentifiable. Crazy. I still have plenty of old equipment running that uses TO3 style transistors and still got plenty of NOS at work. Unless you find an old techie that's was used to repairing these 50 year old things…you're just about SOL. I got old Motorola paging units that go on to a VHF radio for hospitals and fire departments, some of them I had to junk, because of one unidentifiable I.C. I think there is a post about it around here somewhere. See… even I don't know all of them Motorola equivalents.
Sometimes you're better off to find a device that uses this part. Then study the schematic and see what that circuit does and go from there. Problem with that is that not everything has a schematic available anymore because they are that old.
I still have NOS ECG packaged things by boxes full.

[eccerr0r]

If it was a popular part...why is there no documentation about it and why are some wrong...?

hmm...calculating backwards I need a transistor that can handle 4 amps... and already in my spare parts bin...

Then the other question is if I had a pile of darlingtons, do I rewire the PSU to use discrete darlingtons instead of using its discrete transistor to be the predriver of the darlington...

[CapLeaker]

NTE/ECG used to be real good at dealing with custom numbers as well as indicating part manufacturer. But it still stands, my Motorola 10262 and 10261 both could only be and are NPN.

BTW the PSU is made by Power-One which has been bought out by Bel Power. And I substituted a 10262 with a 2n3055, and no magic smoke came out yet...

2N3773 or some MJ15015 or something similar..

[truclacicr]

It seems that NTE/ECG went to a lot of trouble to supply a matched complementary pair. This suggests that there must exist a genuine PNP 10262, but obviously not the same one as the OP's. Maybe there is an audio power amp that uses these same numbers for different parts?

NTE219MCP is a matched complementary pair containing 1 each of NTE219 (PNP) and NTE130 (NPN).

[sam_sam_sam]

Back in the day this was a very popular part number you still find surplus electronic stores that specialize in obsolete parts I still see them around

[eccerr0r]

NTE/ECG used to be real good at dealing with custom numbers as well as indicating part manufacturer. But it still stands, my Motorola 10262 and 10261 both could only be and are NPN.

BTW the PSU is made by Power-One which has been bought out by Bel Power. And I substituted a 10262 with a 2n3055, and no magic smoke came out yet...

[truclacicr]

https://antiqueradios.com/forums/viewtopic.php?t=70011

I have a pair of old linear 5 volt power supplies. One is up and running in a supply for 20's radios the other is not working.

They use Motorola 10261 (ECG 130) and 10262 (ECG 219) transistors.

The 10262 is supposed to be PNP and tests bad as such. What confuses me is that it tests perfect on my Sencore Tansistor Tester when tested as a NPN transistor. The 10261 tests OK as NPN.

I see several listings for SGS versions of the same 10261 and 10262 transistors. This suggests that they may be the house numbers of the PSU manufacturer.

https://i.ebayimg.com/images/g/pJYAA...fq/s-l1600.jpg

https://i.ebayimg.com/images/g/D8wAA...q/s-l1600.webp

[truclacicr]

https://www.sourceresearch.com/StoreWork/CrossList.cfm

10261 = NTE130 -- NPN 100V 15A TO-3 Audio Power Amp, Medium Speed Switch

10262 = NTE219 -- PNP 100V 15A TO-3 General Purpose Amp and Switch, complement to NTE130

https://web.archive.org/web/20220814...pdf/nte130.pdf

[eccerr0r]

Damn, self necro after I found my own post researching repair of an old linear PSU.

I just ran into another 10261 (and three 10262) on a power supply I recently got to do some "solar panel emulator" so I can test at night.

The PSU only makes sense if the 10261 and 10262 are all NPN as the circuit looks like they're darlington connected emitter follower. All collectors are tied together. One emitter connected to three bases and three emitters connected through resistors to output.

The 10261 and 10262 behave like NPN (or dead...) based on a diode checker DMM. However I saw some sites where 10262 is ... PNP ??? This can't be right.

[kc8adu]

Re: Failed Motorola 10261 ... transistor?

since we are cutting transistors this may be of interst.
http://sound.whsites.net/counterfeit.htm

[eccerr0r]

Re: Failed Motorola 10261 ... transistor?

So they just labeled it TO-204 just "because," despite the fact they're identical?

looks like even the cap height has no bearing, and can be over a 0.1" higher and still be in tolerance...

[budm]

Re: Failed Motorola 10261 ... transistor?

https://cdn.badcaps-static.com/pdfs/...3bfced6226.pdf
TO-204 is a newer case designation.

[eccerr0r]

Re: Failed Motorola 10261 ... transistor?

Now what's the difference between TO-3 and TO-204, aluminum vs steel?

Pictured left to right:

2N3055 (aluminum TO-3?) (Silicon NPN)
2SC2930 (steel TO-204?) (Silicon NPN)
103-9 (steel TO-3?) (Germanium PNP)
2N1136A (aluminum flange, steel cap TO-204?) (Germanium PNP)
Guts of the 10261 (TO-3?) (Silicon NPN)

[PeteS in CA]

Re: Failed Motorola 10261 ... transistor?

I think the common bond wire material is aluminum. I wonder if the die-case connection was bad.

Back in ancient times when I opened "TO-3" cases (I think the modern case is TO-204), I used a hack saw very gently, barely breaking through the metal of the dome most of the way around.