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

Model 90 mystery cap
#1

Hello. I finally registered to the Phorum after months of lurking because I finally found a question that hasn't already been addressed here. I'm re-capping my very first Philco, a Model 90 that a friend found at a yard sale in Montana (I won't tell you what he paid for it, but it was CHEAP!).

There seems to be a mystery capacitor connected between the #18 By-Pass Condenser (3903-M) and a terminal on the speaker socket. The value is .05mfd/200v. I haven't seen this cap in any diagram or schematic, and it doesn't appear in the photo that Ron posted elsewhere of a pristine Model 90 chassis. It appears to be from the same era, judging from the paper wrapping and size, so I'm guessing it was attached by a service tech who may not have had access to Philco's secret bakelite cap contents listings.

Question: when I get to that cap, should I just not replace it, and assume that replacing the caps inside 3903-M (which specs at .01mfd) will take care of it, or should I replace the .05mfd external cap as well? What do I risk by removing that cap?

I never would have attempted this re-cap if it weren't for the Phorum and all the incredibly valuable advice I found here. I appreciate all of your collective knowledge and experience!

Thanks,

Mike

[Image: http://i326.photobucket.com/albums/k420/...g:original]
#2

Think I found my way around it, using the Rider's pages posted online. Unfortunately, when I put it all back together, I got bad squeal and BLATT above 900 khz., and decent reception below that. Coils look like they're okay, but some resistors are way off spec, so that's next. I'll let you know how that makes it sound...




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Philco 46-420 Code 121 Reception issues
Welcome Eric, I agree with Bob and far as the two main electrolytic filter capacitors did you change them yourself or w...radiorich — 11:43 PM
Philco 46-420 Code 121 Reception issues
You mentioned the Philco manual and going through the check points...just to be sure we're on the same page here's the m...klondike98 — 08:13 PM
Philco 42-1008 conversion kit
Interesting. I haven't seen that before.klondike98 — 07:02 PM
12' Philco
Yes I had looked for it on the web as well some time back and could not find it. I was glad to see it turned up in Ron'...klondike98 — 06:59 PM
Shadow Meter Bulb
Now if you had a set with a tuning light then the bulb type is important to the circuit, some sets used those prior to t...Arran — 04:58 PM
Shadow Meter Bulb
Ok. Thanks for the correction.RossH — 03:09 PM
Model 28L
For 28 you will probably need to buy a Hammond 125CSE. Or any of the series of the power you need, with SE suffix. Then ...morzh — 02:09 PM
37-60 revision 6
I am restoring a Philco 37-60 and it shows run 6 they removed the ground from G3 of the 6K7G and put the G3 to -2.5v for...bobbyd1200 — 01:01 PM
Shadow Meter Bulb
Mike is correct on the bulb connection, two separate circuits. I found that by rotating the bulb and sliding it forward ...RodB — 12:19 PM
Hickok AC51 tube tester
Cleaned ann contacts, switches and sockets, works great now.martinj — 11:32 AM

[-]
Who's Online
There are currently 3250 online users. [Complete List]
» 4 Member(s) | 3246 Guest(s)
AvatarAvatarAvatarAvatar

>