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
PT-6 antenna connections
Notice in the schematic the notch at the bottom of the antenna coil is between pins 3 & 4.RodB — 07:34 PM
bridkarl
I have two PT-6 chassis. On both there is a blue wire that runs from the above chassis transformer to pin 6 of 7C6. So t...bridkarl — 07:23 PM
Cannot Adjust an IF Transformer’s cores
Joseph, now you are an engineer!!RodB — 06:37 PM
PT-6 antenna connections
Hi, reading your explanation I can see the confusion. If you take it one connection at a time it should result in a desi...RodB — 06:34 PM
Cannot Adjust an IF Transformer’s cores
It works! I received the PCBs this morning in the mail, and put everything together. I reused the base from the original...jrblasde — 04:32 PM
PT-6 antenna connections
I seem to have lost my way on this PT-6. I see the antenna aerial transformer schematic - I’m reading pins 1 through ...bridkarl — 12:30 PM
40-150 General questions
Good thing you're a good electrician ... the pictures show a lot of rewiring in your future! Take care and BE HEALTHY!...GarySP — 11:52 AM
40-150 General questions
I think RobB has it right. It is a part number and looks like its stamped on the chassis and that wasn't something you ...klondike98 — 11:41 AM
40-150 General questions
It's most likely a part number. Most of Philco part numbers are in that format. I looked at the parts list for this mode...RodB — 08:10 AM
40-150 General questions
Hi Kevin, No, I don't but I like your Quote about being a good electrician. The way I look at it is "The fact ...MrFixr55 — 08:06 AM

[-]
Who's Online
There are currently 3040 online users. [Complete List]
» 2 Member(s) | 3038 Guest(s)
AvatarAvatar

>