Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

Model 650 Recap Success then ecap blows
#16

Terry

Yes open choke could have blown 8uF #77 up (this was the reason for me to ask if it was open) but for a different reason.

1. #78 would not blown if its WV is equal or better than the rectifier output. (then again it might be lower though some good tolerances exist for surge and overvoltage, so then you'd be right about it). The cap would only charge to the peak amplitude value whatever it is, usually on the orxer of 500V (this is why I have them rated 500V).
Then again it is not the #78 that blew, but 77.
2. The reason an open choke (notice I am not saying "disconnected") could blow up the #77 is simple: it has cam #80 in parallel. That in turn would result a polarised #77 cap subjected to the AC voltage which is known to make them blow. Of course this would depend on the ripple amplitude and the latter quickly cones to almost zero as the 78 has charged so after all it might not be the case.

In this case we have good 80 tube, good (believed to be) choke and good caps. Possible disconnecting of the 10uF #77 is almost immaterial. So....it is a mistery.

People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.




Users browsing this thread: 4 Guest(s)
[-]
Recent Posts
Philco Model 71B
Is the arch area on the front of a Model 20 real or photo?MrFixr55 — 07:31 PM
Eico 584 schematic
Anyone have a schematic for this tester?daveone23 — 05:48 PM
Philco Model 71B
Good one!!! No if I go for it, I’ll fix it right lolslford310 — 04:38 PM
Philco Model 71B
Stucco on the arch?RodB — 04:31 PM
Philco Model 76 Highboy
Back in Feb I scored a nice model 95 Highboy, see earlier post.  Saved from a guy that likes chopping them up into Liquo...slford310 — 09:49 AM
Philco Model 71B
Adding a pic from the other side and the inside.  It will be a bit of work and a challenge but that's what makes it fun....slford310 — 09:32 AM
Philco 89B code 123 newbie
Hi Kurt Welcome to the Philco Phorum. Lots of phriendly pholks (see a pattern here?) who are happy to help.  Keep posti...MrFixr55 — 08:36 AM
Philco 89B code 123 newbie
Hello Kurt, Welcome aboard and you have a nice set to start on ! Yes, the bakelite blocks and I too find them fairly...radiorich — 07:12 AM
Philco 89B code 123 newbie
Getting started on my first Philco here, done some research and hopefully I now know enough to be dangerous.  :) Overal...Kurt P — 01:44 AM
Delco car radio Peko vibrator converstion issues
Richard, I reviewed the Panasonic specification sheets for this type capacitor and though dV/dt is discussed, there a...Chas — 11:48 AM

[-]
Who's Online
There are currently no members online.

>