1970s RCA TRIACs

[BurningTantalum]

Yesterday I spent a happy hour digging the hard silicone potting compound out of a Mercury outboard CDI unit. The main switching device appeared to be a triac of RCA manufacture dated 1978. It had failed completely all ways round, possibly due to the external rubber covered wires having lost their rubber or my non-electronic friend's attempts to 'test it' with a 12v car battery.
I replaced the triac with a general 400V TO220 and the unit works fine when linked up to my test rig - a 1980 Johnson 15hp.
Suitably encouraged I have dug into a second different unit and found two RCA triacs of a similar type. The first triac is RCA 66375 and the second pair are RCA 66133. They are TO8 cases; like a big TO5.
Purely out of interest- does anyone have any info on these devices? I can find nothing on the net, a 1960s catalogue does not list them.

[smjcuk]

RCA are a pain. They seem to have had a crisis of half bothering with JEDEC numbering and then not bothering and then bothering again. I've got a bunch of RCA power transistors here that aren't in an RCA catalogue, don't have JEDEC numbers but do have a 6 digit RCA part. I'm wondering if they provided specialist one offs to some companies. Fortunately a random guessing and finger crossing picked that 2n3055 worked as a substitute for mine!

[oldway]

I have never seen a CDI unit using a triac...always a SCR (thyristor).
Are sure it is a triac ?

[BurningTantalum]

Thanks both of you.
The units are both for twin cylinder motors but are slightly different in design.
Of course the second unit with two switching devices are thyristors, I posted without thinking !  In effect there are to separate circuits, as in the old OMC units.
This is now repaired and running.

The first unit is definitely a triac- I replaced it with one and the unit works fine. There are two 1.5uF caps that charge opposite polarities from the magneto coil via suitable diodes; the triac is triggered and the relevant cap discharges via the associated coil- one cap one way through the triac and the other cap the other way through the triac. I have not seen this before, but don't make a habit of trowelling out the potting compound from these units ! Just a favour for a friend.

BT