03-15-2015, 07:50 PM
Here's an example of having to be careful about stuffing the bakelite block caps. They don't always follow the wiring scheme shown in Service Bulletin No. 289. In the schematic
[Image: https://www.dropbox.com/s/fczysxvhrrnqym....jpg?raw=1]
the bakelite block cap of interest for this discussion is # 33, an 8035-D block. [Image: https://www.dropbox.com/s/z3iyy5swefh7qx....jpg?raw=1]
Service Bulletin 164A notes that 8035-D is to be replaced with 8035-EU. If you look up 8035-EU in Service Bulletin 289 it shows two caps (110pf and 0.015uf wired with 110pf in lugs 1 & 3 and the 0.015uF in lugs 1 & 2 (and because its labeled "U", lug 1 is not supposed to be grounded). However if you look at the schematic for cap#33 above, you see that the 110pf cap is grounded on one end and has the 75 tube plate in common with the 0.015uF cap. To make this work under the chassis, lug #1 of the block is grounded and the caps are wired with 110pF in 1 & 3 and the 0.015uF cap in 2 & 3. So....pay attention to the schematics as you stuff these! I'm sure this is old hat to the veterans but only the second time I've come across it. Just about ready to insert the caps (if you're observant, you'll note I've got the lead to be grounded at lug #1 on the far right...it should go on the left into the block but I did wire it right when I did it....I think )...
[Image: https://www.dropbox.com/s/g6g5yvx78ats7f....jpg?raw=1]
[Image: https://www.dropbox.com/s/fczysxvhrrnqym....jpg?raw=1]
the bakelite block cap of interest for this discussion is # 33, an 8035-D block. [Image: https://www.dropbox.com/s/z3iyy5swefh7qx....jpg?raw=1]
Service Bulletin 164A notes that 8035-D is to be replaced with 8035-EU. If you look up 8035-EU in Service Bulletin 289 it shows two caps (110pf and 0.015uf wired with 110pf in lugs 1 & 3 and the 0.015uF in lugs 1 & 2 (and because its labeled "U", lug 1 is not supposed to be grounded). However if you look at the schematic for cap#33 above, you see that the 110pf cap is grounded on one end and has the 75 tube plate in common with the 0.015uF cap. To make this work under the chassis, lug #1 of the block is grounded and the caps are wired with 110pF in 1 & 3 and the 0.015uF cap in 2 & 3. So....pay attention to the schematics as you stuff these! I'm sure this is old hat to the veterans but only the second time I've come across it. Just about ready to insert the caps (if you're observant, you'll note I've got the lead to be grounded at lug #1 on the far right...it should go on the left into the block but I did wire it right when I did it....I think )...
[Image: https://www.dropbox.com/s/g6g5yvx78ats7f....jpg?raw=1]