Electrolytic Cap on Model 650 question
Posts: 26
Threads: 9
Joined: Nov 2020
City: Ottawa
State, Province, Country: Ontario
https://philcoradio.com/library/download...l.%201.pdf
Working on changing the caps on this Model 650 and was wondering what voltage is required for Part #71, the 1, 2, and 3 mfd electrolytic. As well is is ok to just use a non polarized film cap here. I have those on hand but would have to order the electrolytic caps. Thanks.
Posts: 1,400
Threads: 70
Joined: Oct 2007
City: Linn Creek, MO
Bob, I would definitely use film caps, they will practically last forever, not so for electrolytics.
Steve
M R Radios C M Tubes
Posts: 15,444
Threads: 539
Joined: Oct 2011
City: Jackson, NJ
The #71 cap's values, as long as they meet the sch values, are OK. You could use 10uF all around if you have this cap available already and do not want to buy more caps. 450V is my minimum voltage, 500V is preferred.
Yes you could use film caps, as Steve has already said.
The only cap you might want to have as close as possible to the value is the #78 an 8uF one.
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.
Posts: 26
Threads: 9
Joined: Nov 2020
City: Ottawa
State, Province, Country: Ontario
Thanks gentlemen. I appreciate your knowledge and assistance.
Posts: 1,472
Threads: 89
Joined: May 2008
City: Omak
State, Province, Country: WA
Hello bob,
Film caps are good choice because I need to replace the filter capacitors in my Philco 610b that restored about 20 years ago anyway this time I am using Film capacitors !
Sincerely Richard
Posts: 15,444
Threads: 539
Joined: Oct 2011
City: Jackson, NJ
I have always advocated the view that electrolytic caps are being badmouthed unfairly.
Yes, if using GP caps, which are higher impedance and not high ripple current-rated, they will go dry eventually. Not all, in fact, but mostly those in the very first rectifier filter position.
These caps experience high peak ripple and some significant RMS ripple, which, along with voltage/temperature eventually lead to their deterioration.
However, properly sized electrocyltic caps will last if not forever, then at least many, many tens of years. And typically they are cheaper than comparable good quality film caps.
I use Panasonic high ripple-low impedance 105C-rated caps. They are about $1 apiece in qty of 10+.
Another key is, of course, regular usage. Caps that do not get usage behave same as those in long storage and need re-forming due to developing thinning dielectric layer which is maintained when the cap experienced voltage across it.
This said, it is a matter of taste. I have a generous supply 22uF 450V caps from Panasonic, and I use them most everywhere in the rectifier filters. If I need 10uF, I serialize two 22uF.
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.
Posts: 1,472
Threads: 89
Joined: May 2008
City: Omak
State, Province, Country: WA
Hello Guys,
my go to years ago were sprague atoms now I use nichicon !
Posts: 15,444
Threads: 539
Joined: Oct 2011
City: Jackson, NJ
Any Japanese company will make good caps. Nichicon, Chemi-con, Rubicon, Panasonic.
I was searching for the highest ripple rating at 120 Hz, and found Panasonic to ve the highest, but of course there will be close matches or even better ones, undiscovered by me.
Just do not use no-names, or Lelon, or.....
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: 1 Guest(s)
|
|
Recent Posts
|
|
Cannot Adjust an IF Transformer’s cores
|
| Outstanding work indeed. I wish I could come up with solutions like this.slford310 — 11:16 PM |
|
Cannot Adjust an IF Transformer’s cores
|
| The abilities of our 'Phorum Pholks" never ceases to amaze me! Fantastic fabrication, Joseph! I'm waiting now for...GarySP — 08:27 PM |
|
PT-6 antenna connections
|
| Thanks. I never realized that was a notch noted in the schematic as described. I’ll recheck my wiring.bridkarl — 08:13 PM |
|
Cannot Adjust an IF Transformer’s cores
|
| Thank you! I was quite new to the Phorum when I started this post, so I feel like it might be advantageous to publish a ...jrblasde — 08:07 PM |
|
PT-6 antenna connections
|
| Notice in the schematic the notch at the bottom of the antenna coil is between pins 3 & 4.
Yes, pin 6 of the 7C6 is...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 |
|
Who's Online
|
| There are currently no members online. |
|
 
|
![[-]](https://philcoradio.com/phorum/images/bootbb/collapse.png "[-]")
