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Philco 90 Ball of Confusion! - Printable Version

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Philco 90 Ball of Confusion! - madghost - 02-18-2009

Hello All,
I have a Philco cathedral model 90 with one 47 tube. Somebody who had this radio before me did some work to repair/modify the set. In doing so, they jumped a number of the caps by wiring the connection out side of the bakleite blocks. To do this, they cut off some of the lugs, making my job tougher, as I am trying to restore the chassis back to original wiring. I have the schematic, the diagram showing where the major components are and a parts list. I have rebuilt several of the bakelite blocks and have been able to figure out and properly replace the caps in the blocks, solder them to the correct lugs, resolder the cut off lugs where necessary and re wire several resistors back to their correct location.
My problem is with C 18 and the correct location of several resistors and other connections. Parts list shows C-18 as 3903-M with condesor lugs used at #4 and #7 lugs. Additional lug used is # 8. R 50 is supposed to be connected to lug#7 and one of C-30 conection to #7 as well as R 49 (coming all the way from the RF socket). R 17 is supposed to be connected to lug 8. However, I do not see a wire from the cap inside the block soldered to lug 8 but to lug #7 instead. Lug 4 does have a cap wire attached. Also, R 50 is connected to lug 8 along with R 17 and R49. C- 30 should go to 7, but is connected to 8. I have noticed that someone scratched an R into the side of the block, which could mean someone made a mod, because a 3903 R does use lugs 7 and 4. But doesn't this change the resistor and other cap connections? How should I proceed?
I know this was a long post, but I had to describe my challenge in detail. This one ball of confusion!

Re: Philco 90 Ball of Confusion! - Ron Ramirez - 02-19-2009

Hi Madghost

Welcome back! Long time no see. Icon_smile

I have a 90 chassis with 1-47 output; let me take a look at it after work tonight...

Re: Philco 90 Ball of Confusion! - madghost - 02-19-2009

Thanks Ron! I just retired from the Marine Corps and moved to Pa late last year. Lot's of stuff going on and things have settled down to the point where I can find some time to work on a couple of radios. Looking forward to your reply.
SF/MG

Re: Philco 90 Ball of Confusion! - Ron Ramirez - 02-19-2009

Mine has a 3903-R as part ( 18 ) also, with the letter R scratched into the side of the block. It has lugs at 4, 7 and 8.

Lug 4 has a wire running to volume control (20), also mica condenser (19) from lug 4 to ground at the mounting lug of ( 18 ).

Lug 7 has resistor (17) connected to it.

Lug 8 has resistor (50), a wire from multi-section condenser (30) and a wire running to resistor (49) connected to it.

The .01 uF condenser inside the block connects to lugs 4 and 7.

Hope this helps,

Ron.

Re: Philco 90 Ball of Confusion! - madghost - 02-20-2009

Ron, thanks for the response. I connected the components as you described. Of course, now the radio doesn't play Icon_razz , but then again, I did not check it each time I put in a new cap or re arranged the wiring back to original RATS! I noticed also that the RF 27 tube does not appear to light up. How did I manage to screw that up? The radio was working before I started the recap/re-wire process, but had significant oscillating problems and sound was very uneven a not very clear (which is the major reason I wanted to do the recap)
A couple of thoughts; have we found a new shcematic /parts diagram error? Again, my parts list calls for a C-18 3903-M for C-18, not R type. The schematic does not seem to jive with the parts diagram and did not notice any changes made in the Riders about a substitution for a 3903-M for and R. I also have concerns about R 1 and R 49 and where they are supposed to be gorunded. Schematic shows they are to be grounded to chassis, but the parts diagram is unclear and they are currently grounded to the # 1 lug of C-35 (which is OK I guess, but why different than what the diagram seems to show?
Would you or anyone else out there on the Phorum have a good photo of the underside of the chassis so I can confirm my wiring /component placement?
Lastly, the parts list shows 4 electrolytic caps (a 6 and 10 at C-56 and a 6 and 10 at C-57). Were the Mershon cans dual electrolytics? It is not obvious to me by the shcematic.
Thanks again for all your help.
SF/MG