Just found a sealed packet with a D90 diode, THORN part number 01P0-910-001
Packet also marked C1574, TC2360 and 0X5-758
Any ideas to what it is? Or equivalent type?
Thanks in advance
Ah, the wonderful Thorn classification system, don't you just love it! My workshop is full of these Thorn packets, I got a large stock from an ex Thorn engineer a few years back.
D59 is just listed as a bias diode.
As you may or may not know, Thorn had this classification system for components. “AF=Audio", “OP=Output", “RF (self-explanatory)”, “TVT=Transistor", VS=Voltage stabiliser and "D=Diode".
In this case, the D59 packet will list all the diodes in that classification, that are OK to use. Therefore, in your pack if it lists D90, C1574, TC2360 and OX5-758, they are all diode equivalents and any can be used in the circuit position. Interestingly, C1574 is a transistor, I assume if used to be configured as a diode.
Quite why thorn did this is beyond me, it just seems to add a layer of confusion. However, I suspect inside Thorn it made perfect sense and to Thorn dealerships likewise. It's only when folk like us outside of Thorn get them, we go Huh!
John (Jayceebee) & Jim (Jcdaze) both Ex Thorn TV engineers, will I'm sure, correct me if I've got any of this wrong, or have further to add.
If you have a look at this, it should start to be a little clearer.
Thanks. I just got the eyeglass out and it has TC2360 printed on it. Still none the wiser as I rely on my 1968 Mullard data book for anything as old as this.
I just put the diode in my super duper Chinese tester and it has a firward voltage of 0.6v and a capacitance of 43pF so I guess its silicon
I presume it allowed Thorn to source components from many vendors, choosing the best value which could be different from order to order as suppliers vied for the sale.