VOLTIX 420-C5 OSCILLOSCOPE – This is the first heavy equipment I have purchased. I was very proud of it at that time. Of course it was, even at that time, too old and obsolete, but I didn't care. As much old, heavy and ugly, as best for me!! Before it I had only my SAEHAN ST-360TR multimeter that my dad gave me in 1995. I bought this scope in early 1997 at a third-hand store on Santa Ifigênia, here in São Paulo. Santa Ifigênia is a group of 10 or 12 blocks that have stores devoted to electronics (in 1997 almost all stores were selling electronics stuff), and some of them sold these kind of equipments, that they bought from Factories that had closed or just renewed their rigs. Nowadays it is very hard to find these equipments there since that place is almost taken by computer stores. Electronics are being left to the underground.
There was myself carrying it on my shoulders down to Avenida São João. I took the subway and went to my sister's home. Needless to say that everybody was staring at me with that "what the hell is he carrying" look. At that time I was living in Presidente Prudente. I paid R$50, something about USD$45 nowadays (refer to this currency converter). That store had a lot of good equipment and a reasonable price. It was the same store that my dad bought the 386, the first computer we had. At that day I remember that they had an old Tektronix scope, with some modules missing, but I had not enough money to pay for it. The Tek was working, but one channel had its module taken off. I don't remember the model, but they asked R$120 for it at that day. Money......
The 420-C5 was in a good fashion, I did a sand-spray on it, and electrostatic painting. It looked like new. All ranges were working just fine. But it was only AC coupled, and many tests I just couldn't do with it. Here are the schematics of 420-C5. And here is the compilation of the original one, that I made with ExpressPCB. Some values are missing and I will insert it as soon as I got time to open the cabinet and read them. The original will also be available at BAMA .
Basically this scope is a copy from the Heathkit O-11, with few differences. Coincidence or not, I will acquire an O-11 many years later. The basic specifications of the 420-C5 are below:
So, now I'm working on insert Vertical DC coupling capability on this unit. I will not damage the panel neither the inner chassis. All mods will be totally reversible. The new model 420-C5/2 can be seen here.