looking for a schmatic for a '72 GE color set

[drh4683]

I got a chance to sit down and really check out the latest no HV regulation problem this evening. HV corona is caused by some carbon build up on the HV lead that is soldered onto the HV rectifier socket. GE used some interesting type of HV "caulk" on and around those pins. When it drys, it drys very pourous and very flexible. Well, it carboned up and was shorting to ground. I pulled that junk off and still had a little bit of hiss to deal with as the HV lead has a carbon hole burned through the insulation which just needs to be snipped and resoldered, its right at the end of the wire.

Fortunately, I got the HV regulation issue fixed. Diode Y252 in the HV regulation circuit (to the grid circuit of the 26HU5 HOT) was wide open. I had a variable grid voltage from -65 through -72 volts. Supposed to be -70, but no rectified pulse. I didnt get any reading with my vtvm when checking the diode forward or reverse biased. Its a rather large diode, brown in color about 3/4" long, 3/16" OD. I used some gator clips and attached a 1000 PIV 1amp silicon diode and the HV hiss arcing suddenly dissapeared (HV finally dropped down!). I now had a perfect control of HV from 20KV to 27KV.
Since I only have tekfax (schematic only, no parts list), Id like to find out what the proper substitution is for this diode Y252. Just so you know, this particular chassis only has the one diode. Supposedly there were other versions that had two diodes in parallel (Y252, and Y253) and the circuit in my C2 is slightly different as this chassis has a focus potentiometer, and not a focus coil like the schematic shows, so I dont have the two 430K ohm resistors nor the 3900pF disk cap. My C2 chassis was built in April, 1972. I dont know enough about these GE sets. I dont know if my set is an early or late production.
Thanks again for all your help.