Hey guys, I always hate it when people post questions about something and then never follow-up with how things worked out. As I don't want to do that myself, I am now posting a little more about this project. It has been a wild since my last post as the ovens owner has been busy with some family stuff.
First thing, I found out what the oven is and why fixing it is very preferable to buying a new one. The oven is an old GE Spacemaker Installed new in 1980. I'm posting three links below to show you what this oven looks like. It is installed above the stove just like shown in the first and second link. The problem is the shape of the old oven, nobody makes one like that anymore. It is the same height as the new ones that you can buy in the rear, but at the front it is thinner, and angles down from front to back. The problem is not getting an oven to fit in the existing space, it is that if you put it there it is too close to the front burners on the stove and renders the stove basically unusable. Mounting it up higher requires modifying the cabinet above it, which will cost a bit to get done by the time you are done with modifications and painting etc. Also, the cabinet above it will then not be very tall and will no longer be able to hold the items which are normally stored there.
https://www.pinterest.com/pin/ge-spacemaker-microwave-1980--94364554670268081/https://artsandculture.google.com/asset/advertisement-for-1978-spacemaker-microwave-oven/GAG4e8ZCiko92Ahttps://www.reddit.com/r/PcBuildHelp/comments/b2e1sj/ive_acquired_an_old_general_electric_spacemaker/As to my suspicion that it may use phase control for power, that is definitely incorrect. I asked, and he said you can definitely hear it cycle on and off at lower power settings. Part of the reason I suspected it might be phase controlled is that it does have a separate transformer for the filament. I assume they did this to eliminate the constant cycling of the filament at reduced power settings, which I always thought was a terrible idea.
As to whether to use a zero switching triac or not, I missed a bit of a clue earlier. When I was trying to figure out what the Opto was, one of the post was from "wraper" and I failed to notice, but he provided an SK part number for a replacement of the original Motorola 01S63. This is not a zero switching part, I will replace the part I installed accordingly.
Now onto the fun part, the original large triac. The owner removed it and brought it to me the other day, my DMM seemed to show A1 and A2 shorted, and the gate completely disconnected. Nice to see the part was actually bad, but this would not explain the oven not heating or the small Opto getting fried. So I decided to test it a little further, and it was quite an interesting test. I hope test leads to A1 and A2, and fed them with my Power Designs 6050. I measured the voltage drop at the terminals with a fluke 8040 a/af. Initially, it performs like a low value but somewhat unstable resistor. I think I was getting something like 2V drop at 2A, It would keep going up to about 3 or 4 V, past that it would suddenly drop down to 2V Again. Obviously a defective part, but they should actually make the oven run at full power constantly and would not explain the failure of the Opto.
Well, after I guess somewhere between 30 seconds and a minute, the device was starting to get warm. All of a sudden the current drops to zero, and stays there even when I crank to supply all the way up to 60 V. So I decide to try triggering it. What happens when you do this is
completely random. Sometimes the gate will not even draw current, sometimes it triggers like it should but will turn off after a few seconds even with 5A flowing through it. Sometimes it will just turn on and off like a relay as quickly as you can apply and remove power from the gate, and sometimes it must be parking internally or something, as it makes noises like a scratchy volume control while the current meter jumps all over the place. Also, even though the terminals are not at all loose, applying pressure to any of them can cause its behavior to change. Clearly this triac is the source of all the problems.
Thanks to all who offered advice, I will make a final post about whether it works or not when it is done. I am almost certain that it will.
Ed