655 restoration - Printable Version
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RE: 655 restoration - radiorich - 04-21-2023
Hello Pat,
It is fairly easy to stuff the cans just depends if you want to stuff the orinigal capacitors or mount them under the chassis like chas talked about that is the easiest way.
Sincerely Richard
RE: What's My Model? - patmat2350 - 04-24-2023
Cap stuffing!
I've emptied all the Bakelites and gutted the e-cap cans, and I just received a bunch of new caps from JustRadios.
For the cans, I have a little variation: Just because I have the material and a lathe, I turned new bases from solid PVC bar. Cap leads come out the bottom and attach to screwed-in solder lugs. This includes the leads that would go to the trapped side lugs on the cans, so the cans are now isolated from circuitry.
One can is an 8 & 10 μF combo. I was about to rebuild it by blithely tying the negative leads together... nope! Read the dang schematic, duh. They're in series.
New turned base with solder lugs for the 8μF ecap:
ecap secured with a glob of gooey glue:
Assembled with insulator and clamp- solid:
Not the can above... but another can combines e-caps 58 & 61... in series.
RE: What's My Model? - Steve Davis - 04-24-2023
It looks like you have the polarity of cap 61 reversed, the - should go to the center tap of the HV winding and the + should go to chassis ground. Always remember, the HV center tap is the lowest voltage point of the radio.
Steve
RE: What's My Model? - patmat2350 - 04-24-2023
Hmmm, so much for my understanding of grounds and center taps... thanks! I hate blowing up e-caps...
RE: What's My Model? - radiorich - 04-24-2023
Hello Pat,
The stuffed can capacitor looks great nice job !
What Steve said that is so true don't ask me how I know !
I was working on a Sony receiver in college back in the 80s and did just that reversed the caps around it made large bang !!
Sincerely richard
RE: 655 restoration - patmat2350 - 04-26-2023
So my posts on this radio have been split, recombined, moved, closed... I'll figure out the correct logic for posting yet! Maybe right after I figure out the true meaning of life, and my 655 schematic... ;-)
In another place, I asked about a mystery resistor across the shadow meter leads... it's not on the schematic or parts finder. The schematic seems to show 300 ohm across the meter coil, but no mention of this resistor. And other models seem to show various values when they do show this shunt resistor,
I asked about the resistor's color code... I finally found the explanation here at Shop Talk, so all is good, and I also found a bit of a hidden stripe on this resistor- it's not green with red dot, it's green body-black stripe-red dot, making it a 5k.
For the discussion at Shop Talk- I'd add a clarification for the slow-witted (like me): If there is no stripe, then the stripe = body color!
Solid white with orange dot is then Wt-Wt-Or, or 99,000 ohm.
RE: 655 restoration - patmat2350 - 04-26-2023
OK, a question about the filament wiring.
The 655 schematic has the typical format, with filament transformer winding grounded on one side, and an arrow off to the filaments. It also shows most of the cathodes connected to one filament pin AND ground.
I've traced all my wiring (I think), and see:
- NO grounding of the filament circuit anywhere,
- NO connections of cathodes to filament circuit.
Is there any deeper understanding to be had for this situation? I suppose it doesn't matter that the filaments are on their own floating circuit, but why show it differently in the schematic?
EDIT: I'm clearly missing something in my wire tracing, and yet further puzzlement: With all tubes pulled, BOTH sides of the filament circuit measure ZERO ohms to chassis.
How does THAT work?
655 schematic, at transformer:
655 schematic, typical tubes with cathode-filament-ground connections shown:
Actual layout in chassis- No filament grounds, No connection to cathodes:
RE: 655 restoration - patmat2350 - 04-26-2023
A comment on wiring colors:
I found the section here in Shop Talk on this subject, and extracted:
(starting 1934-ish)
RED . . . . . . . . . Filaments and odd wires
BROWN . . . . . . . Cathodes and grounds
WHITE . . . . . . . . B+ and screens of output pentodes
WHITE w/BLACK tracer and/or BLACK w/WHITE tracer . . . . Plates
GREEN . . . . . . . . Grids and screen grids
Reality in my 1936/7-ish 655:
Tan: Both sides of the floating heater (filaments) circuit, and a bunch of other places including cathodes;
Brown (and black): Leads out of the transformer
White, and white with black tracer: LOOKS like tan! But closer inspection and the pic below show it's lighter than TAN and could have been white once!
RE: 655 restoration - patmat2350 - 04-27-2023
I lied. One side of the filament circuit is tied to the 6A7 cathode. And there are branches off to the pilot and shadow tuner bulbs.
But I'm still getting zero ohms to chassis from BOTH sides of the filament circuit, even with the bulbs and tubes all removed. So still puzzled.
RE: 655 restoration - patmat2350 - 04-27-2023
Tuner Clean & Lube!
The 655 has a friction drive from the main tuner knob to the "hoop", and a sprung-ball clutch drive thing for the fine tuning knob. Mine was pretty stiff, and the whole tuner was somewhat filthy. Parts were disassembled, cleaned, lubed and reassembled. Here's the result- smooth! Now waiting on new rubber mounts from Renovated Radios...
[Video: https://youtu.be/SdBKLcLTrZw]
Hoop is trapped between a sprung plate and the bearing body- arrow:
Pull the shaft/bearing/bracket off:
Pull the shaft unit apart and clean the old grease out of everything. When reassembling, the balls ride on the arced part of shaft on right:
Reassembled shaft unit:
Tuner itself was cleaned with soapy water and a toothbrush. No need for dishwashers or ultrasonics:
Tone Control Rebuild - patmat2350 - 04-27-2023
Working on a 655 tone control, 30-4378.
I have rebuilt all my Bakelites, is it the same process on this unit? Like to know before I dig in!
Am I right in assuming that it contains THREE caps? It has 3 leads into the wax from the contacts, and one coming out. The parts list says cap 41 0.01 is part of "Program Control" (tone control) 42, but there's no mention of the other 0.01 and the 3000pF caps. I think all 3 are in there, would make sense based on the leads.
And the insulation on the leads into the wax have turned to goo... guess I'm diving in there regardless.
The tone control:
Wires:
RE: Tone Control Rebuild - patmat2350 - 04-27-2023
Answered my own Q. Looked at the 660 schematic with probably a very similar tone control unit... all 3 caps are clearly shown as part of the unit.
RE: 655 restoration - admin - 04-27-2023
Patmat2350
Please stop creating multiple threads on the same subject radio. This is a violation of Phorum rules.
Read the following thread.
https://philcoradio.com/phorum/showthread.php?tid=4586
Thank you.
RE: 655 restoration - patmat2350 - 04-27-2023
Many apologies- I saw it as a separate discussion topic (Philco tone controls), rather than something specific to THIS one radio.
I'll keep it all in one box now.
RE: 655 restoration - Ron Ramirez - 04-27-2023
I looked at the complete 655 service bulletin.
https://philcoradio.com/library/download/service%20info/service%20bulletins/Philco%20Service%20Bulletin%20235.pdf
It shows part (41) separate from part (42) which is the tone control with two capacitors.
However
Looking at the parts list, this states that part (41) is indeed part of (42).
So, yes, part (42) does indeed contain three capacitors - two .01 uF and one .003 uF (3000 pF, or as morzh likes to say, 3 nF).
Remember, always study the service information of the radio in question so you do not make any mistakes. Of course, this does not count the times where Philco included errors in their service info...but isn't that what makes this sort of thing, ah, fun or something?
