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Help finding specs for transistor - RCA K68 = Motorola K68MEX
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SilverSolder:

--- Quote from: amyk on April 15, 2020, 02:44:21 am ---If K68 is 2N6688, then is K75 2N6758 ? A 2N6758 is also in a TO-3 case but unfortunately it's a N MOSFET, so that theory is dead... but you can check some of the other parameters like Vbe and Vce(sat) to see if they match.

Also, I think "MEX" is just Mexico, where they were made.

--- End quote ---

Testing Vce(sat) is a bit of a challenge, i.e. finding a power supply capable of 20A - 30A...   Maybe I can use a car battery or something...

Or perhaps a pulse load would work,  out of a suitably big capacitor?



vk6zgo:

--- Quote from: SilverSolder on April 14, 2020, 01:28:46 am ---
Some progress!

In the same bag of transistors, there were two Motorola transistors marked Motorola (logo) K68MEX, datecoded '85.

Presumably, these are equivalent to the RCA K68 since they (a) were found in the same bag, and (b) have similar part numbers (K68)

Sadly, searching for the Motorola part number yielded no results either...  but at least it is clear that the part was made by more than one manufacturer.  Is it perhaps less likely that it was a custom marked part if it was available from two different manufacturers?

--- End quote ---

I would guess "MEX" meant the devices were manufactured in Mexico, as I have seen that suffix on other more well known types.
We often received mixed bags of devices, some with "MEX" on them, & some without.

Very early RCA devices used the prefix "CK", maybe an early Silicon power device, with the "C" omitted?

I know most early power devices were germanium PNP, but there were definitely some odd types out there.

Some very early "transistor radios" had NPN germanium small signal devices, but they were pretty much swamped by the flood of early PNP germaniums in the "OC xx"series & their "2Nxxx" & "2Sxxxx" counterparts.

Philips & Mullard actually made a few real "bipolar transistors" (they had interchangeable emitter & collectors for "special applications", the details of which are lost in the mists of time.)
SilverSolder:

--- Quote from: vk6zgo on April 16, 2020, 02:48:25 am ---
--- Quote from: SilverSolder on April 14, 2020, 01:28:46 am ---
Some progress!

In the same bag of transistors, there were two Motorola transistors marked Motorola (logo) K68MEX, datecoded '85.

Presumably, these are equivalent to the RCA K68 since they (a) were found in the same bag, and (b) have similar part numbers (K68)

Sadly, searching for the Motorola part number yielded no results either...  but at least it is clear that the part was made by more than one manufacturer.  Is it perhaps less likely that it was a custom marked part if it was available from two different manufacturers?

--- End quote ---

I would guess "MEX" meant the devices were manufactured in Mexico, as I have seen that suffix on other more well known types.
We often received mixed bags of devices, some with "MEX" on them, & some without.

Very early RCA devices used the prefix "CK", maybe an early Silicon power device, with the "C" omitted?

I know most early power devices were germanium PNP, but there were definitely some odd types out there.

Some very early "transistor radios" had NPN germanium small signal devices, but they were pretty much swamped by the flood of early PNP germaniums in the "OC xx"series & their "2Nxxx" & "2Sxxxx" counterparts.

Philips & Mullard actually made a few real "bipolar transistors" (they had interchangeable emitter & collectors for "special applications", the details of which are lost in the mists of time.)

--- End quote ---

Looks like we are talking 1980's here, based on the date codes on these devices.  The Vbe measures as 559mV, which points to silicon rather than germanium.

I'm still thinking hard about how to generate a 20A test current to measure Vce(sat)!   :-\

I can get to 15A with my beefiest supply...   might as well be 1.5A  for all the good that does...
Laser Fish:
Hi, I know I might be a little late to the table but I've come across the same transistors. Hence; your form. However I was fortunate enough to come across a RCA 2N6308 in the same lot. I don't know enough about these parts to tell if it's ~similar / match, but I thought someone on this form could tell. LMK also typical applications. Thanks, LF
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