View Single Post
  #5  
Old 02-05-2017, 07:32 PM
MadMan's Avatar
MadMan MadMan is offline
The Resident Brony
 
Join Date: Oct 2016
Location: Chicago
Posts: 1,217
So I was at my grandpa's house today, shovelling a van-load of junk out of his garage. He had SO MUCH useless paperwork EVERYWHERE, that it didn't surprise me that he had file folders in his garage desk. What did surprise me was that as I poked through them, I saw an orange Simpson manual. Turns out, I stumbled upon the mother lode of Simpson manuals, original design and schematic drawings, and a whole bunch of other neat stuff. A lot of which directly links him to the design of several Simpson products. Pretty neat, eh?

But more importantly, I found these:



A tad surprising, since he said this pair belonged to his colleague and not him. But hey, I'm not complaining! In a couple days, I'm gonna order a bunch of caps for these and other projects, and get these going.

Oh! And question, guys: the scope has 9 capacitors that are 0.5uf 400/200v. Would it be ok to replace them with 0.47uf orange dips? 0.5uf are expensive
EDIT: Never mind, the manual calls for +/- 20% caps. With math, a +/-10% 0.47uf will still be within tolerance.


Quote:
Originally Posted by Tubejunke View Post
I can't think of what would have smoked out in that scope just by plugging it in that wouldn't leave some sort of evidence. It will be interesting to find out what that was. Let us know...
I looked over the schematic - now that I have it - and it sure looks like a resistor is completely missing across 2 big caps. And if I recall correctly, that area is the place I suspected. I'll take pics later, but I really just can't tell that anything was there. It must've blown the leads off of the joints. Maybe once I desolder them, I'll know. Also, looking over the caps and whatnot, I noticed a few things being awry. The can cap was replaced, the replacement missing a segment, which was replaced with a dry electrolytic that's half the uf it's supposed to be. There's an extra resistor, missing capacitor, and this rig has an unoccupied tube socket on the side that's been cut off from everything, and isn't in the schematic, and doesn't appear in the photo. But the place the socket goes sure looks like it was stamped out, not drilled. In-house experimental rig, I'd say.

Quote:
Originally Posted by dieseljeep View Post
I had the larger model of the scope. I just bought it for parts, as the seller said the power transformer was shot, which it was.
I was surprised to see them using a 5Y3 instead of a 1V2, that most tube scopes used.
There was a bigger Simpson scope? The only one I know of was the Genescope.

Quote:
Originally Posted by jr_tech View Post
When I was in high school, I had an old Eico 425 that also used a 5Y3 as a hv rectifier... tube layout was very similar except it use octal tubes like 6SN7, 6J5 instead of the smaller 7 & 9 pin tubes in this Simpson 'scope. Extremely basic 'scope, using a 5BP1 CRT.

jr
This one seems a bit simple as well. Probably a good thing, given I'm gonna be working on it. O_o

Last edited by MadMan; 02-06-2017 at 11:27 PM.
Reply With Quote
Audiokarma