I'm trying to repair an Electric Shepherd ESB 250 electric fence energizer (12 volt battery driven) Its problem is the use of non-Milspec components which have steel leadout wires. As it is a battery fencer it will have been used outside in all weathers and the damp atmosphere has corroded away the leads on several resistors and diodes (join steel and copper then get them damp = a corrosion cell) There is one glass diode with bands White Black White Black but the black bands are very thin. I thought that it might be a 1N9090 but this number does not compute. Probing up the hole where the lead used to be shows that it is a diode (the lead at its other end is still OK) It looks like I will have to reverse-bias what is left of it to try to discover its Zener voltage. Curiously the PCB had been varnished by the makers but it looks as if the varnish was also not Milspec. IMHO car body cavity wax protects better than varnish but of course nothing lasts forever. If anyone can ID that weird diode I'd be very interested to know what it is.
Update I have just discovered that there is a 1N99 but whether this is it I don't know. The 1N99 is Germanium which is rather surprising but of course the unit is very old. Unfortunately the circuit diagrams for these things seem to be Trade Secrets as the makers would really like their customers to buy new products.
Update I have just discovered that there is a 1N99 but whether this is it I don't know. The 1N99 is Germanium which is rather surprising but of course the unit is very old. Unfortunately the circuit diagrams for these things seem to be Trade Secrets as the makers would really like their customers to buy new products.
